php-doc-en/appendices/migration80/incompatible.xml

<?xml version="1.0" encoding="utf-8"?>
<!-- $Revision$ -->

<sect1 xml:id="migration80.incompatible" xmlns:xlink="http://www.w3.org/1999/xlink">
 <title>Backward Incompatible Changes</title>

 <sect2 xml:id="migration80.incompatible.core">
  <title>PHP Core</title>

  <sect3 xml:id="migration80.incompatible.core.string-number-comparision">
   <title>String to Number Comparison</title>

   <para>
    Non-strict comparisons between numbers and non-numeric strings now work by casting the number to
    string and comparing the strings. Comparisons between numbers and numeric strings continue to
    work as before. Notably, this means that <code>0 == "not-a-number"</code> is considered false
    now.
    <informaltable>
     <tgroup cols="3">
      <thead>
       <row>
        <entry>Comparison</entry>
        <entry>Before</entry>
        <entry>After</entry>
       </row>
      </thead>
      <tbody>
       <row>
        <entry><code>0 == "0"</code></entry>
        <entry>&true;</entry>
        <entry>&true;</entry>
       </row>
       <row>
        <entry><code>0 == "0.0"</code></entry>
        <entry>&true;</entry>
        <entry>&true;</entry>
       </row>
       <row>
        <entry><code>0 == "foo"</code></entry>
        <entry>&true;</entry>
        <entry>&false;</entry>
       </row>
       <row>
        <entry><code>0 == ""</code></entry>
        <entry>&true;</entry>
        <entry>&false;</entry>
       </row>
       <row>
        <entry><code>42 == "   42"</code></entry>
        <entry>&true;</entry>
        <entry>&true;</entry>
       </row>
       <row>
        <entry><code>42 == "42foo"</code></entry>
        <entry>&true;</entry>
        <entry>&false;</entry>
       </row>
      </tbody>
     </tgroup>
    </informaltable>
    <!-- RFC: https://wiki.php.net/rfc/string_to_number_comparison -->
   </para>
  </sect3>

  <sect3 xml:id="migration80.incompatible.core.other">
   <title>Other incompatible Changes</title>

   <itemizedlist>
    <listitem>
     <para>
      <literal>match</literal> is now a reserved keyword.
     </para>
    </listitem>
    <listitem>
     <para>
      <literal>mixed</literal> is now a reserved word, so it cannot be used to name a class, interface or trait, and is also prohibited from being used in namespaces.
     </para>
    </listitem>
    <listitem>
     <para>
      Assertion failures now throw by default. If the old behavior is desired,
      <code>assert.exception=0</code> can be set in the INI settings.
     </para>
    </listitem>
    <listitem>
     <para>
      Methods with the same name as the class are no longer interpreted as constructors. The
      <link linkend="object.construct">__construct()</link> method should be used instead.
     </para>
    </listitem>
    <listitem>
     <para>
      The ability to call non-static methods statically has been removed. Thus
      <function>is_callable</function> will fail when checking for a non-static method with a classname
      (must check with an object instance).
     </para>
    </listitem>
    <listitem>
     <para>
      The <code>(real)</code> and <code>(unset)</code> casts have been removed.
     </para>
    </listitem>
    <listitem>
      <para>
       The <link linkend="ini.track-errors">track_errors</link> ini directive has been removed. This
       means that <varname>php_errormsg</varname> is no longer available. The
       <function>error_get_last</function> function may be used instead.
      </para>
    </listitem>
    <listitem>
     <para>
      The ability to define case-insensitive constants has been removed. The third argument to
      <function>define</function> may no longer be &true;.
     </para>
    </listitem>
    <listitem>
     <para>
      The ability to specify an autoloader using an <function>__autoload</function> function has been
      removed. <function>spl_autoload_register</function> should be used instead.
     </para>
    </listitem>
    <listitem>
     <para>
      The <parameter>errcontext</parameter> argument will no longer be passed to custom error handlers
      set with <function>set_error_handler</function>.
     </para>
    </listitem>
    <listitem>
     <para>
      <function>create_function</function> has been removed. Anonymous functions may be used instead.
     </para>
    </listitem>
    <listitem>
     <para>
      <function>each</function> has been removed. &foreach; or <classname>ArrayIterator</classname>
      should be used instead.
     </para>
    </listitem>
    <listitem>
     <para>
      The ability to unbind <varname>this</varname> from closures that were created from a method,
      using <methodname>Closure::fromCallable</methodname> or
      <methodname>ReflectionMethod::getClosure</methodname>, has been removed.
     </para>
    </listitem>
    <listitem>
     <para>
      The ability to unbind <varname>this</varname> from proper closures that contain uses of
      <varname>this</varname> has also been removed.
     </para>
    </listitem>
    <listitem>
     <para>
      The ability to use <function>array_key_exists</function> with objects has been removed.
      <function>isset</function> or <function>property_exists</function> may be used instead.
     </para>
    </listitem>
    <listitem>
     <para>
      The behavior of <function>array_key_exists</function> regarding the type of the
      <parameter>key</parameter> parameter has been made consistent with <function>isset</function> and
      normal array access. All key types now use the usual coercions and array/object keys throw a
      <classname>TypeError</classname>.
     </para>
    </listitem>
    <listitem>
     <para>
      Any array that has a number <replaceable>n</replaceable> as its first numeric key will use
      <replaceable>n+1</replaceable> for its next implicit key, even if <replaceable>n</replaceable> is
      negative.
      <!-- RFC: https://wiki.php.net/rfc/negative_array_index -->
     </para>
    </listitem>
    <listitem>
     <para>
      The default error_reporting level is now <constant>E_ALL</constant>. Previously it excluded
      <constant>E_NOTICE</constant> and <constant>E_DEPRECATED</constant>.
     </para>
    </listitem>
    <listitem>
     <para>
      <link linkend="ini.display-startup-errors">display_startup_errors</link> is now enabled by
      default.
     </para>
    </listitem>
    <listitem>
     <para>
      Using <type>parent</type> inside a class that has no parent will now result in a fatal
      compile-time error.
     </para>
    </listitem>
    <listitem>
     <para>
      The <literal>@</literal> operator will no longer silence fatal errors
      (<constant>E_ERROR</constant>, <constant>E_CORE_ERROR</constant>,
      <constant>E_COMPILE_ERROR</constant>, <constant>E_USER_ERROR</constant>,
      <constant>E_RECOVERABLE_ERROR</constant>, <constant>E_PARSE</constant>). Error handlers that
      expect error_reporting to be <literal>0</literal> when <literal>@</literal> is used, should be
      adjusted to use a mask check instead:
     </para>
     <para>
      <programlisting role="php">
<![CDATA[
<?php
// Replace
function my_error_handler($err_no, $err_msg, $filename, $linenum) {
    if (error_reporting() == 0) {
        return false;
    }
    // ...
}

// With
function my_error_handler($err_no, $err_msg, $filename, $linenum) {
    if (!(error_reporting() & $err_no)) {
        return false;
    }
    // ...
}
?>
]]>
      </programlisting>
     </para>
     <para>
      Additionally, care should be taken that error messages are not displayed in production
      environments, which can result in information leaks. Please ensure that
      <code>display_errors=Off</code> is used in conjunction with error logging.
     </para>
    </listitem>
    <listitem>
     <para>
      <literal>#[</literal> is no longer interpreted as the start of a comment,
      as this syntax is now used for attributes.
      <!-- RFC: https://wiki.php.net/rfc/shorter_attribute_syntax_change -->
     </para>
    </listitem>
    <listitem>
     <para>
      Inheritance errors due to incompatible method signatures (LSP violations) will now always
      generate a fatal error. Previously a warning was generated in some cases.
      <!-- RFC: https://wiki.php.net/rfc/lsp_errors -->
     </para>
    </listitem>
    <listitem>
     <para>
      The precedence of the concatenation operator has changed relative to bitshifts and addition as
      well as subtraction.
     </para>
     <para>
      <programlisting role="php">
<![CDATA[
<?php
echo "Sum: " . $a + $b;
// was previously interpreted as:
echo ("Sum: " . $a) + $b;
// is now interpreted as:
echo "Sum:" . ($a + $b);
?>
]]>
      </programlisting>
      <!-- RFC: https://wiki.php.net/rfc/concatenation_precedence -->
     </para>
    </listitem>
    <listitem>
     <para>
      Arguments with a default value that resolves to &null; at runtime will no longer implicitly mark
      the argument type as nullable. Either an explicit nullable type, or an explicit &null; default
      value has to be used instead.
     </para>
     <para>
      <programlisting role="php">
<![CDATA[
<?php
// Replace
function test(int $arg = CONST_RESOLVING_TO_NULL) {}
// With
function test(?int $arg = CONST_RESOLVING_TO_NULL) {}
// Or
function test(int $arg = null) {}
?>
]]>
      </programlisting>
     </para>
    </listitem>
    <listitem>
     <para>
      A number of warnings have been converted into <classname>Error</classname> exceptions:
     </para>
     <para>
      <simplelist>
       <member>
        Attempting to write to a property of a non-object. Previously this
        implicitly created an stdClass object for null, false and empty strings.
       </member>
       <member>
        Attempting to append an element to an array for which the PHP_INT_MAX key
        is already used.
       </member>
       <member>
        Attempting to use an invalid type (array or object) as an array key or
        string offset.
       </member>
       <member>Attempting to write to an array index of a scalar value.</member>
       <member>Attempting to unpack a non-array/Traversable.</member>
       <member>
        Attempting to access unqualified constants which are undefined.
        Previously, unqualified constant accesses resulted in a warning and were interpreted as strings.
       </member>
      </simplelist>
     </para>
     <para>
      A number of notices have been converted into warnings:
     </para>
     <para>
      <simplelist>
       <member>Attempting to read an undefined variable.</member>
       <member>Attempting to read an undefined property.</member>
       <member>Attempting to read an undefined array key.</member>
       <member>Attempting to read a property of a non-object.</member>
       <member>Attempting to access an array index of a non-array.</member>
       <member>Attempting to convert an array to string.</member>
       <member>Attempting to use a resource as an array key.</member>
       <member>Attempting to use null, a boolean, or a float as a string offset.</member>
       <member>Attempting to read an out-of-bounds string offset.</member>
       <member>Attempting to assign an empty string to a string offset.</member>
      </simplelist>
      <!-- RFC: https://wiki.php.net/rfc/engine_warnings -->
     </para>
    </listitem>
    <listitem>
     <para>
      Attempting to assign multiple bytes to a string offset will now emit a warning.
     </para>
    </listitem>
    <listitem>
     <para>
      Unexpected characters in source files (such as NUL bytes outside of strings) will now result in a
      <classname>ParseError</classname> exception instead of a compile warning.
     </para>
    </listitem>
    <listitem>
     <para>
      Uncaught exceptions now go through "clean shutdown", which means that destructors will be called
      after an uncaught exception.
     </para>
    </listitem>
    <listitem>
     <para>
      The compile time fatal error "Only variables can be passed by reference" has been delayed until
      runtime, and converted into an "Argument cannot be passed by reference"
      <classname>Error</classname> exception.
     </para>
    </listitem>
    <listitem>
     <para>
      Some "Only variables should be passed by reference" notices have been converted to "Argument
      cannot be passed by reference" exception.
     </para>
    </listitem>
    <listitem>
     <para>
      The generated name for anonymous classes has changed. It will now include the name of the first
      parent or interface:
     </para>
     <para>
      <programlisting role="php">
<![CDATA[
<?php
new class extends ParentClass {};
// -> ParentClass@anonymous
new class implements FirstInterface, SecondInterface {};
// -> FirstInterface@anonymous
new class {};
// -> class@anonymous
?>
]]>
      </programlisting>
     </para>
     <para>
      The name shown above is still followed by a NUL byte and a unique suffix.
     </para>
    </listitem>
    <listitem>
     <para>
      Non-absolute trait method references in trait alias adaptations are now required to be
      unambiguous:
     </para>
     <para>
      <programlisting role="php">
<![CDATA[
<?php
class X {
    use T1, T2 {
        func as otherFunc;
    }
    function func() {}
}
?>
]]>
      </programlisting>
     </para>
     <para>
      If both <code>T1::func()</code> and <code>T2::func()</code> exist, this code was previously
      silently accepted, and func was assumed to refer to <code>T1::func</code>. Now it will generate a
      fatal error instead, and either <code>T1::func</code> or <code>T2::func</code> needs to be
      written explicitly.
     </para>
    </listitem>
    <listitem>
     <para>
      The signature of abstract methods defined in traits is now checked against the implementing class
      method:
     </para>
     <para>
      <programlisting role="php">
<![CDATA[
<?php
trait MyTrait {
    abstract private function neededByTrait(): string;
}

class MyClass {
    use MyTrait;

    // Error, because of return type mismatch.
    private function neededByTrait(): int { return 42; }
}
?>
]]>
      </programlisting>
      <!-- RFC: https://wiki.php.net/rfc/abstract_trait_method_validation -->
     </para>
    </listitem>
    <listitem>
     <para>
      Disabled functions are now treated exactly like non-existent functions. Calling a disabled
      function will report it as unknown, and redefining a disabled function is now possible.
     </para>
    </listitem>
    <listitem>
     <para>
      <literal>data://</literal> stream wrappers are no longer writable, which matches the documented
      behavior.
     </para>
    </listitem>
    <listitem>
     <para>
      The arithmetic and bitwise operators <literal>+</literal>, <literal>-</literal>,
      <literal>*</literal>, <literal>/</literal>, <literal>**</literal>, <literal>%</literal>,
      <literal>&lt;&lt;</literal>, <literal>&gt;&gt;</literal>, <literal>&amp;</literal>,
      <literal>|</literal>, <literal>^</literal>, <literal>~</literal>, <literal>++</literal>,
      <literal>--</literal> will now consistently throw a <classname>TypeError</classname> when one of
      the operands is an &array;, &resource; or non-overloaded &object;. The only exception to this is
      the array <literal>+</literal> array merge operation, which remains supported.
      <!-- RFC: https://wiki.php.net/rfc/arithmetic_operator_type_checks -->
     </para>
    </listitem>
    <listitem>
     <para>
      Float to string casting will now always behave locale-independently.
     </para>
     <para>
      <programlisting role="php">
<![CDATA[
<?php
setlocale(LC_ALL, "de_DE");
$f = 3.14;
echo $f, "\n";
// Previously: 3,14
// Now:        3.14
?>
]]>
      </programlisting>
     </para>
     <para>
      See <function>printf</function>, <function>number_format</function> and
      <methodname>NumberFormatter</methodname> for ways to customize number formatting.
      <!-- RFC: https://wiki.php.net/rfc/locale_independent_float_to_string -->
     </para>
    </listitem>
    <listitem>
     <para>
      Support for deprecated curly braces for offset access has been removed.
     </para>
     <para>
      <programlisting role="php">
<![CDATA[
<?php
// Instead of:
$array{0};
$array{"key"};
// Write:
$array[0];
$array["key"];
?>
]]>
      </programlisting>
      <!-- RFC: https://wiki.php.net/rfc/deprecate_curly_braces_array_access -->
     </para>
    </listitem>
    <listitem>
     <para>
      Applying the final modifier on a private method will now produce a warning unless that method is
      the constructor.
      <!-- FC: https://wiki.php.net/rfc/inheritance_private_methods -->
     </para>
    </listitem>
    <listitem>
     <para>
      If an object constructor <function>exit</function>s, the object destructor will no longer be
      called. This matches the behavior when the constructor throws.
     </para>
    </listitem>
    <listitem>
     <para>
      Namespaced names can no longer contain whitespace: While <code>Foo\Bar</code> will be recognized
      as a namespaced name, <code>Foo \ Bar</code> will not. Conversely, reserved keywords are now
      permitted as namespace segments, which may also change the interpretation of code:
      <code>new\x</code> is now the same as <code>constant('new\x')</code>, not
      <code>new \x()</code>.
      <!-- RFC: https://wiki.php.net/rfc/namespaced_names_as_token -->
     </para>
    </listitem>
    <listitem>
     <para>
      Nested ternaries now require explicit parentheses.
      <!-- RFC: https://wiki.php.net/rfc/ternary_associativity -->
     </para>
    </listitem>
    <listitem>
     <para>
      <function>debug_backtrace</function> and <methodname>Exception::getTrace</methodname> will no
      longer provide references to arguments. It will not be possible to change function arguments
      through the backtrace.
     </para>
    </listitem>
    <listitem>
     <para>
      Numeric string handling has been altered to be more intuitive and less error-prone. Trailing
      whitespace is now allowed in numeric strings for consistency with how leading whitespace is
      treated. This mostly affects:
     </para>
     <para>
      <simplelist>
       <member>The <function>is_numeric</function> function</member>
       <member>String-to-string comparisons</member>
       <member>Type declarations</member>
       <member>Increment and decrement operations</member>
      </simplelist>
     </para>
     <para>
      The concept of a "leading-numeric string" has been mostly dropped; the cases where this remains
      exist in order to ease migration. Strings which emitted an <constant>E_NOTICE</constant> "A non
      well-formed numeric value encountered" will now emit an <constant>E_WARNING</constant> "A
      non-numeric value encountered" and all strings which emitted an <constant>E_WARNING</constant> "A
      non-numeric value encountered" will now throw a
      <classname>TypeError</classname>. This mostly affects:
     </para>
     <para>
      <simplelist>
       <member>Arithmetic operations</member>
       <member>Bitwise operations</member>
      </simplelist>
     </para>
     <para>
      This <constant>E_WARNING</constant> to <classname>TypeError</classname> change also affects the
      <constant>E_WARNING</constant> "Illegal string offset 'string'" for illegal string offsets. The
      behavior of explicit casts to int/float from strings has not been changed.
      <!-- RFC: https://wiki.php.net/rfc/saner-numeric-strings -->
     </para>
    </listitem>
    <listitem>
     <para>
      Magic Methods will now have their arguments and return types checked if they have them declared.
      The signatures should match the following list:
     </para>
     <para>
      <simplelist>
       <member><code>__call(string $name, array $arguments): mixed</code></member>
       <member><code>__callStatic(string $name, array $arguments): mixed</code></member>
       <member><code>__clone(): void</code></member>
       <member><code>__debugInfo(): ?array</code></member>
       <member><code>__get(string $name): mixed</code></member>
       <member><code>__invoke(mixed $arguments): mixed</code></member>
       <member><code>__isset(string $name): bool</code></member>
       <member><code>__serialize(): array</code></member>
       <member><code>__set(string $name, mixed $value): void</code></member>
       <member><code>__set_state(array $properties): object</code></member>
       <member><code>__sleep(): array</code></member>
       <member><code>__unserialize(array $data): void</code></member>
       <member><code>__unset(string $name): void</code></member>
       <member><code>__wakeup(): void</code></member>
      </simplelist>
      <!-- RFC: https://wiki.php.net/rfc/magic-methods-signature -->
     </para>
    </listitem>
    <listitem>
     <para>
      <function>call_user_func_array</function> array keys will now be interpreted as parameter names,
      instead of being silently ignored.
     </para>
    </listitem>
    <listitem>
     <para>
      Declaring a function called <literal>assert()</literal> inside a namespace is
      no longer allowed, and issues <constant>E_COMPILE_ERROR</constant>.
      The <function>assert</function> function is subject to special handling by the engine,
      which may lead to inconsistent behavior when defining a namespaced function with the same name.
     </para>
    </listitem>
   </itemizedlist>
  </sect3>
 </sect2>

 <sect2 xml:id="migration80.incompatible.resource2object">
  <title>Resource to Object Migration</title>

  <para>
   Several &resource;s have been migrated to &object;s.
   Return value checks using <function>is_resource</function> should be replaced with checks for &false;.
  </para>
  <itemizedlist>
    <listitem>
     <para>
      <function>curl_init</function> will now return a <classname>CurlHandle</classname> object rather
      than a &resource;. The <function>curl_close</function> function no longer has an effect,
      instead the <classname>CurlHandle</classname> instance is automatically destroyed if it is no
      longer referenced.
     </para>
    </listitem>
    <listitem>
     <para>
      <function>curl_multi_init</function> will now return a <classname>CurlMultiHandle</classname>
      object rather than a &resource;. The <function>curl_multi_close</function> function no
      longer has an effect, instead the <classname>CurlMultiHandle</classname> instance is
      automatically destroyed if it is no longer referenced.
     </para>
    </listitem>
    <listitem>
     <para>
      <function>curl_share_init</function> will now return a <classname>CurlShareHandle</classname>
      object rather than a &resource;. The <function>curl_share_close</function> function no
      longer has an effect, instead the <classname>CurlShareHandle</classname> instance is
      automatically destroyed if it is no longer referenced.
     </para>
    </listitem>
   <listitem>
    <para>
     <function>enchant_broker_init</function> will now return an <classname>EnchantBroker</classname>
     object rather than a &resource;.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>enchant_broker_request_dict</function> and
     <function>enchant_broker_request_pwl_dict</function> will now return an
     <classname>EnchantDictionary</classname> object rather than a &resource;.
    </para>
   </listitem>
   <listitem>
    <para>
     The GD extension now uses <classname>GdImage</classname> objects as the underlying data structure
     for images, rather than &resource;s.
     The <function>imagedestroy</function> function no longer has an effect; instead the
     <classname>GdImage</classname> instance is automatically destroyed if it is no longer referenced.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>openssl_x509_read</function> and <function>openssl_csr_sign</function> will now return
     an <classname>OpenSSLCertificate</classname> object rather than a &resource;.
     The <function>openssl_x509_free</function> function is deprecated and no longer has an effect,
     instead the <classname>OpenSSLCertificate</classname> instance is automatically destroyed if it
     is no longer referenced.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>openssl_csr_new</function> will now return an
     <classname>OpenSSLCertificateSigningRequest</classname> object rather than a &resource;.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>openssl_pkey_new</function> will now return an
     <classname>OpenSSLAsymmetricKey</classname> object rather than a &resource;.
     The <function>openssl_pkey_free</function> function is deprecated and no longer has an effect,
     instead the <classname>OpenSSLAsymmetricKey</classname> instance is automatically destroyed if it
     is no longer referenced.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>shmop_open</function> will now return a <classname>Shmop</classname> object rather than
     a &resource;. The <function>shmop_close</function> function no longer has an effect, and is
     deprecated; instead the <classname>Shmop</classname> instance is automatically destroyed if it is
     no longer referenced.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>socket_create</function>, <function>socket_create_listen</function>,
     <function>socket_accept</function>, <function>socket_import_stream</function>,
     <function>socket_addrinfo_connect</function>, <function>socket_addrinfo_bind</function>, and
     <function>socket_wsaprotocol_info_import</function> will now return a
     <classname>Socket</classname> object rather than a &resource;.
     <function>socket_addrinfo_lookup</function> will now return an array of
     <classname>AddressInfo</classname> objects rather than &resource;s.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>msg_get_queue</function> will now return an <classname>SysvMessageQueue</classname>
     object rather than a &resource;.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>sem_get</function> will now return an <classname>SysvSemaphore</classname> object
     rather than a &resource;.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>shm_attach</function> will now return an <classname>SysvSharedMemory</classname> object
     rather than a &resource;.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>xml_parser_create</function> and <function>xml_parser_create_ns</function> will now
     return an <classname>XMLParser</classname> object rather than a &resource;. The
     <function>xml_parser_free</function> function no longer has an effect, instead the XMLParser
     instance is automatically destroyed if it is no longer referenced.
    </para>
   </listitem>
   <listitem>
    <para>
     The <link linkend="book.xmlwriter">XMLWriter</link> functions now accept and return, respectively,
     <classname>XMLWriter</classname> objects instead of &resource;s.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>inflate_init</function> will now return an <classname>InflateContext</classname> object
     rather than a &resource;.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>deflate_init</function> will now return a <classname>DeflateContext</classname> object
     rather than a &resource;.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.com">
  <title>COM and .Net (Windows)</title>

  <para>
   The ability to import case-insensitive constants from type libraries has been removed.
   The second argument to <function>com_load_typelib</function> may no longer be false;
   <link linkend="ini.com.autoregister-casesensitive">com.autoregister_casesensitive</link>
   may no longer be disabled; case-insensitive markers in
   <link linkend="ini.com.typelib-file">com.typelib_file</link> are ignored.
  </para>
 </sect2>

 <sect2 xml:id="migration80.incompatible.curl">
  <title>CURL</title>

  <para>
   <constant>CURLOPT_POSTFIELDS</constant> no longer accepts objects as arrays. To
   interpret an object as an array, perform an explicit <code>(array)</code> cast. The
   same applies to other options accepting arrays as well.
  </para>
 </sect2>

 <sect2 xml:id="migration80.incompatible.datetime">
  <title>Date and Time</title>

  <para>
   <function>mktime</function> and <function>gmmktime</function> now require at least one
   argument. <function>time</function> can be used to get the current timestamp.
  </para>
 </sect2>

 <sect2 xml:id="migration80.incompatible.dom">
  <title>DOM</title>

  <para>
   Unimplemented classes from the DOM extension that had no behavior and contained test
   data have been removed. These classes have also been removed in the latest version of
   the DOM standard:
  </para>
  <para>
   <simplelist>
    <member><classname>DOMNameList</classname></member>
    <member><classname>DomImplementationList</classname></member>
    <member><classname>DOMConfiguration</classname></member>
    <member><classname>DomError</classname></member>
    <member><classname>DomErrorHandler</classname></member>
    <member><classname>DOMImplementationSource</classname></member>
    <member><classname>DOMLocator</classname></member>
    <member><classname>DOMUserDataHandler</classname></member>
    <member><classname>DOMTypeInfo</classname></member>
    <member><classname>DOMStringExtend</classname></member>
   </simplelist>
  </para>
  <para>
   Unimplemented methods from the DOM extension that had no behavior have been removed:
  </para>
  <para>
   <simplelist>
    <member><methodname>DOMNamedNodeMap::setNamedItem</methodname></member>
    <member><methodname>DOMNamedNodeMap::removeNamedItem</methodname></member>
    <member><methodname>DOMNamedNodeMap::setNamedItemNS</methodname></member>
    <member><methodname>DOMNamedNodeMap::removeNamedItemNS</methodname></member>
    <member><methodname>DOMText::replaceWholeText</methodname></member>
    <member><methodname>DOMNode::compareDocumentPosition</methodname></member>
    <member><methodname>DOMNode::isEqualNode</methodname></member>
    <member><methodname>DOMNode::getFeature</methodname></member>
    <member><methodname>DOMNode::setUserData</methodname></member>
    <member><methodname>DOMNode::getUserData</methodname></member>
    <member><methodname>DOMDocument::renameNode</methodname></member>
   </simplelist>
  </para>
 </sect2>

 <sect2 xml:id="migration80.incompatible.enchant">
  <title>Enchant</title>

  <itemizedlist>
   <listitem>
    <para>
     <function>enchant_broker_list_dicts</function>, <function>enchant_broker_describe</function> and
     <function>enchant_dict_suggest</function> will now return an empty array instead of &null;.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.exif">
  <title>Exif</title>

  <para>
   <function>read_exif_data</function> has been removed; <function>exif_read_data</function>
   should be used instead.
  </para>
 </sect2>

 <sect2 xml:id="migration80.incompatible.filter">
  <title>Filter</title>

  <itemizedlist>
   <listitem>
    <para>
     The <constant>FILTER_FLAG_SCHEME_REQUIRED</constant> and
     <constant>FILTER_FLAG_HOST_REQUIRED</constant> flags for the
     <constant>FILTER_VALIDATE_URL</constant> filter have been removed. The <literal>scheme</literal>
     and <literal>host</literal> are (and have been) always required.
    </para>
   </listitem>
   <listitem>
    <para>
     The <constant>INPUT_REQUEST</constant> and <constant>INPUT_SESSION</constant> source for
     <function>filter_input</function> etc. have been removed. These were never implemented and their
     use always generated a warning.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.gd">
  <title>GD</title>

  <itemizedlist>
   <listitem>
    <para>
     The deprecated function <function>image2wbmp</function> has been removed.
     <!-- RFC: https://wiki.php.net/rfc/image2wbmp -->
    </para>
   </listitem>
   <listitem>
    <para>
     The deprecated functions <function>png2wbmp</function> and <function>jpeg2wbmp</function> have
     been removed.
     <!-- RFC: https://wiki.php.net/rfc/deprecate-png-jpeg-2wbmp -->
    </para>
   </listitem>
   <listitem>
    <para>
     The default <parameter>mode</parameter> parameter of <function>imagecropauto</function> no longer
     accepts <literal>-1</literal>. <constant>IMG_CROP_DEFAULT</constant> should be used instead.
    </para>
   </listitem>
   <listitem>
    <para>
     On Windows, <filename>php_gd2.dll</filename> has been renamed to <filename>php_gd.dll</filename>.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.gmp">
  <title>GMP</title>

  <para>
   <function>gmp_random</function> has been removed. One of <function>gmp_random_range</function> or
   <function>gmp_random_bits</function> should be used instead.
  </para>
 </sect2>

 <sect2 xml:id="migration80.incompatible.iconv">
  <title>Iconv</title>

  <para>
   iconv implementations which do not properly set <varname>errno</varname> in case of errors are no
   longer supported.
  </para>
 </sect2>

 <sect2 xml:id="migration80.incompatible.imap">
  <title>IMAP</title>

  <itemizedlist>
   <listitem>
    <para>
     The unused <parameter>default_host</parameter> argument of <function>imap_headerinfo</function>
     has been removed.
    </para>
   </listitem>
   <listitem>
    <para>
     The <function>imap_header</function> function which is an alias of
     <function>imap_headerinfo</function> has been removed.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.intl">
  <title>Internationalization Functions</title>

  <itemizedlist>
   <listitem>
    <para>
     The deprecated constant <constant>INTL_IDNA_VARIANT_2003</constant> has been removed.
     <!-- RFC: https://wiki.php.net/rfc/deprecate-and-remove-intl_idna_variant_2003 -->
    </para>
   </listitem>
   <listitem>
    <para>
     The deprecated <constant>Normalizer::NONE</constant> constant has been removed.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.ldap">
  <title>LDAP</title>

  <itemizedlist>
   <listitem>
    <para>
     The deprecated functions <function>ldap_sort</function>,
     <function>ldap_control_paged_result</function> and
     <function>ldap_control_paged_result_response</function> have been removed.
    </para>
   </listitem>
   <listitem>
    <para>
     The interface of <function>ldap_set_rebind_proc</function> has changed; the
     <parameter>callback</parameter> parameter does not accept empty strings anymore; &null; should be
     used instead.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.mbstring">
  <title>MBString</title>

  <itemizedlist>
   <listitem>
    <para>
     The <link linkend="ini.mbstring.func-overload">mbstring.func_overload</link> directive has been
     removed. The related <constant>MB_OVERLOAD_MAIL</constant>,
     <constant>MB_OVERLOAD_STRING</constant>, and <constant>MB_OVERLOAD_REGEX</constant> constants
     have also been removed. Finally, the <literal>"func_overload"</literal> and
     <literal>"func_overload_list"</literal> entries in <function>mb_get_info</function> have been
     removed.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>mb_parse_str</function> can no longer be used without specifying a result array.
    </para>
   </listitem>
   <listitem>
    <para>
     A number of deprecated mbregex aliases have been removed. See the following
     list for which functions should be used instead:
    </para>
    <para>
     <simplelist>
      <member><function>mbregex_encoding</function> → <function>mb_regex_encoding</function></member>
      <member><function>mbereg</function> → <function>mb_ereg</function></member>
      <member><function>mberegi</function> → <function>mb_eregi</function></member>
      <member><function>mbereg_replace</function> → <function>mb_ereg_replace</function></member>
      <member><function>mberegi_replace</function> → <function>mb_eregi_replace</function></member>
      <member><function>mbsplit</function> → <function>mb_split</function></member>
      <member><function>mbereg_match</function> → <function>mb_ereg_match</function></member>
      <member><function>mbereg_search</function> → <function>mb_ereg_search</function></member>
      <member><function>mbereg_search_pos</function> → <function>mb_ereg_search_pos</function></member>
      <member><function>mbereg_search_regs</function> → <function>mb_ereg_search_regs</function></member>
      <member><function>mbereg_search_init</function> → <function>mb_ereg_search_init</function></member>
      <member><function>mbereg_search_getregs</function> → <function>mb_ereg_search_getregs</function></member>
      <member><function>mbereg_search_getpos</function> → <function>mb_ereg_search_getpos</function></member>
      <member><function>mbereg_search_setpos</function> → <function>mb_ereg_search_setpos</function></member>
     </simplelist>
    </para>
   </listitem>
   <listitem>
    <para>
     The <literal>e</literal> modifier for <function>mb_ereg_replace</function> has been removed.
     <function>mb_ereg_replace_callback</function> should be used instead.
    </para>
   </listitem>
   <listitem>
    <para>
     A non-string pattern argument to <function>mb_ereg_replace</function> will now be interpreted as
     a string instead of an ASCII codepoint. The previous behavior may be restored with an explicit
     call to <function>chr</function>.
    </para>
   </listitem>
   <listitem>
    <para>
     The <parameter>needle</parameter> argument for <function>mb_strpos</function>,
     <function>mb_strrpos</function>, <function>mb_stripos</function>,
     <function>mb_strripos</function>, <function>mb_strstr</function>,
     <function>mb_stristr</function>, <function>mb_strrchr</function> and
     <function>mb_strrichr</function> can now be empty.
    </para>
   </listitem>
   <listitem>
    <para>
     The <parameter>is_hex</parameter> parameter, which was not used internally, has been removed from
     <function>mb_decode_numericentity</function>.
    </para>
   </listitem>
   <listitem>
    <para>
     The legacy behavior of passing the encoding as the third argument instead of an offset for the
     <function>mb_strrpos</function> function has been removed; an explicit <literal>0</literal>
     offset with the encoding should be provided as the fourth argument instead.
    </para>
   </listitem>
   <listitem>
    <para>
     The <literal>ISO_8859-*</literal> character encoding aliases have been replaced by
     <literal>ISO8859-*</literal> aliases for better interoperability with the iconv extension. The
     mbregex ISO 8859 aliases with underscores (<literal>ISO_8859_*</literal> and
     <literal>ISO8859_*</literal>) have also been removed.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>mb_ereg</function> and <function>mb_eregi</function> will now return boolean &true; on
     a successful match. Previously they returned integer <literal>1</literal> if
     <parameter>matches</parameter> was not passed, or <code>max(1, strlen($matches[0]))</code> if
     <parameter>matches</parameter> was passed.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.oci8">
  <title>OCI8</title>

  <itemizedlist>
   <listitem>
    <para>
     The <classname>OCI-Lob</classname> class is now called <classname>OCILob</classname>, and the
     <classname>OCI-Collection</classname> class is now called <classname>OCICollection</classname>
     for name compliance enforced by PHP 8 arginfo type annotation tooling.
    </para>
   </listitem>
   <listitem>
    <para>
     Several alias functions have been marked as deprecated.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>oci_internal_debug</function> and its alias <function>ociinternaldebug</function> have
     been removed.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.odbc">
  <title>ODBC</title>

  <itemizedlist>
   <listitem>
    <para>
     <function>odbc_connect</function> no longer reuses connections.
    </para>
   </listitem>
   <listitem>
    <para>
     The unused <parameter>flags</parameter> parameter of <function>odbc_exec</function> has been
     removed.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.openssl">
  <title>OpenSSL</title>

  <itemizedlist>
   <listitem>
    <para>
     <function>openssl_seal</function> and <function>openssl_open</function> now require
     <parameter>method</parameter> to be passed, as the previous default of <literal>"RC4"</literal>
     is considered insecure.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.pcre">
  <title>Regular Expressions (Perl-Compatible)</title>

  <para>
   When passing invalid escape sequences they are no longer interpreted as literals. This behavior
   previously required the <literal>X</literal> modifier – which is now ignored.
  </para>
 </sect2>

 <sect2 xml:id="migration80.incompatible.pdo">
  <title>PHP Data Objects</title>

  <itemizedlist>
   <listitem>
    <para>
     The default error handling mode has been changed from "silent" to "exceptions". See
     <link linkend="pdo.error-handling">Errors and error handling</link> for details.
     <!-- RFC: https://wiki.php.net/rfc/pdo_default_errmode -->
    </para>
   </listitem>
   <listitem>
    <para>
     The signatures of some PDO methods have changed:
    </para>
    <para>
     <simplelist>
      <member><code>PDO::query(string $query, ?int $fetchMode  = null, mixed  ...$fetchModeArgs)</code></member>
      <member><code>PDOStatement::setFetchMode(int $mode, mixed ...$args)</code></member>
     </simplelist>
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.pdo-odbc">
  <title>PDO ODBC</title>

  <para>
   The &php.ini; directive
   <link linkend="ini.pdo-odbc.db2-instance-name">pdo_odbc.db2_instance_name</link> has been
   removed.
  </para>
 </sect2>

 <sect2 xml:id="migration80.incompatible.pdo-mysql">
  <title>PDO MySQL</title>

  <para>
   <methodname>PDO::inTransaction</methodname> now reports the actual transaction state of
   the connection, rather than an approximation maintained by PDO. If a query that is
   subject to "implicit commit" is executed, <methodname>PDO::inTransaction</methodname>
   will subsequently return &false;, as a transaction is no longer active.
  </para>
 </sect2>

 <sect2 xml:id="migration80.incompatible.pgsql">
  <title>PostgreSQL</title>

  <itemizedlist>
   <listitem>
    <para>
     The deprecated <function>pg_connect</function> syntax using multiple parameters instead of a
     connection string is no longer supported.
    </para>
   </listitem>
   <listitem>
    <para>
     The deprecated <function>pg_lo_import</function> and <function>pg_lo_export</function> signature
     that passes the connection as the last argument is no longer supported. The connection should be
     passed as first argument instead.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>pg_fetch_all</function> will now return an empty array instead of &false; for result
     sets with zero rows.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.phar">
  <title>Phar</title>

  <para>
   Metadata associated with a phar will no longer be automatically unserialized, to fix potential
   security vulnerabilities due to object instantiation, autoloading, etc.
   <!-- RFC: https://wiki.php.net/rfc/phar_stop_autoloading_metadata -->
  </para>
 </sect2>

 <sect2 xml:id="migration80.incompatible.reflection">
  <title>Reflection</title>

  <itemizedlist>
   <listitem>
    <para>
     The method signatures
    </para>
    <para>
     <simplelist>
      <member><code>ReflectionClass::newInstance($args)</code></member>
      <member><code>ReflectionFunction::invoke($args)</code></member>
      <member><code>ReflectionMethod::invoke($object, $args)</code></member>
     </simplelist>
    </para>
    <para>
     have been changed to:
    </para>
    <para>
     <simplelist>
      <member><code>ReflectionClass::newInstance(...$args)</code></member>
      <member><code>ReflectionFunction::invoke(...$args)</code></member>
      <member><code>ReflectionMethod::invoke($object, ...$args)</code></member>
     </simplelist>
    </para>
    <para>
     Code that must be compatible with both PHP 7 and PHP 8 can use the following
     signatures to be compatible with both versions:
    </para>
    <para>
     <simplelist>
      <member><code>ReflectionClass::newInstance($arg = null, ...$args)</code></member>
      <member><code>ReflectionFunction::invoke($arg = null, ...$args)</code></member>
      <member><code>ReflectionMethod::invoke($object, $arg = null, ...$args)</code></member>
     </simplelist>
    </para>
   </listitem>
   <listitem>
    <para>
     The <methodname>ReflectionType::__toString</methodname> method will now return a complete debug
     representation of the type, and is no longer deprecated. In particular the result will include a
     nullability indicator for nullable types. The format of the return value is not stable and may
     change between PHP versions.
    </para>
   </listitem>
   <listitem>
    <para>
     Reflection export() methods have been removed.
     Instead reflection objects can be cast to string.
    </para>
   </listitem>
   <listitem>
    <para>
     <methodname>ReflectionMethod::isConstructor</methodname> and
     <methodname>ReflectionMethod::isDestructor</methodname> now also return &true; for
     <link linkend="object.construct">__construct()</link> and
     <link linkend="object.destruct">__destruct()</link> methods of interfaces.
     Previously, this would only be true for methods of classes and traits.
    </para>
   </listitem>
   <listitem>
    <para>
     <methodname>ReflectionType::isBuiltin</methodname> method has been moved to
     <classname>ReflectionNamedType</classname>. <classname>ReflectionUnionType</classname> does not
     have it.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.sockets">
  <title>Sockets</title>

  <itemizedlist>
   <listitem>
    <para>
     The deprecated <constant>AI_IDN_ALLOW_UNASSIGNED</constant> and
     <constant>AI_IDN_USE_STD3_ASCII_RULES</constant> <parameter>flags</parameter> for
     <function>socket_addrinfo_lookup</function> have been removed.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.spl">
  <title>Standard PHP Library (SPL)</title>

  <itemizedlist>
   <listitem>
    <para>
     <methodname>SplFileObject::fgetss</methodname> has been removed.
    </para>
   </listitem>
   <listitem>
    <para>
     <methodname>SplFileObject::seek</methodname> now always seeks to the beginning of the line.
     Previously, positions <literal>&gt;=1</literal> sought to the beginning of the next line.
    </para>
   </listitem>
   <listitem>
    <para>
     <methodname>SplHeap::compare</methodname> now specifies a method signature. Inheriting classes
     implementing this method will now have to use a compatible method signature.
    </para>
   </listitem>
   <listitem>
    <para>
     <methodname>SplDoublyLinkedList::push</methodname>,
     <methodname>SplDoublyLinkedList::unshift</methodname> and
     <methodname>SplQueue::enqueue</methodname> now return <type>void</type> instead of &true;.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>spl_autoload_register</function> will now always throw a
     <classname>TypeError</classname> on invalid arguments, therefore the second argument
     <parameter>do_throw</parameter> is ignored and a notice will be emitted if it is set to &false;.
    </para>
   </listitem>
   <listitem>
    <para>
     <classname>SplFixedArray</classname> is now an <interfacename>IteratorAggregate</interfacename>
     and not an <interfacename>Iterator</interfacename>.
     <methodname>SplFixedArray::rewind</methodname>, <methodname>SplFixedArray::current</methodname>,
     <methodname>SplFixedArray::key</methodname>, <methodname>SplFixedArray::next</methodname>, and
     <methodname>SplFixedArray::valid</methodname> have been removed. In their place,
     <methodname>SplFixedArray::getIterator</methodname> has been added. Any code which uses explicit
     iteration over SplFixedArray must now obtain an
     <interfacename>Iterator</interfacename> through
     <methodname>SplFixedArray::getIterator</methodname>. This means that
     <classname>SplFixedArray</classname> is now safe to use in nested loops.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.standard">
  <title>Standard Library</title>

  <itemizedlist>
   <listitem>
    <para>
     <function>assert</function> will no longer evaluate string arguments, instead they will be
     treated like any other argument. <code>assert($a == $b)</code> should be used instead of
     <code>assert('$a == $b')</code>. The <link
     linkend="ini.assert.quiet-eval">assert.quiet_eval</link> ini directive and the
     <constant>ASSERT_QUIET_EVAL</constant> constant have also been removed, as they would no longer
     have any effect.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>parse_str</function> can no longer be used without specifying a result array.
    </para>
   </listitem>
   <listitem>
    <para>
     The <link linkend="filters.string.strip_tags">string.strip_tags</link> filter has been removed.
    </para>
   </listitem>
   <listitem>
    <para>
     The <parameter>needle</parameter> argument of <function>strpos</function>,
     <function>strrpos</function>, <function>stripos</function>, <function>strripos</function>,
     <function>strstr</function>, <function>strchr</function>, <function>strrchr</function>, and
     <function>stristr</function> will now always be interpreted as a string. Previously non-string
     needles were interpreted as an ASCII code point. An explicit call to <function>chr</function> can
     be used to restore the previous behavior.
    </para>
   </listitem>
   <listitem>
    <para>
     The <parameter>needle</parameter> argument for <function>strpos</function>,
     <function>strrpos</function>, <function>stripos</function>, <function>strripos</function>,
     <function>strstr</function>, <function>stristr</function> and <function>strrchr</function> can
     now be empty.
    </para>
   </listitem>
   <listitem>
    <para>
     The <parameter>length</parameter> argument for <function>substr</function>,
     <function>substr_count</function>, <function>substr_compare</function>, and
     <function>iconv_substr</function> can now be &null;. &null; values will behave as if no length
     argument was provided and will therefore return the remainder of the string instead of an empty
     string.
    </para>
   </listitem>
   <listitem>
    <para>
     The <parameter>length</parameter> argument for <function>array_splice</function> can now be
     &null;. &null; values will behave identically to omitting the argument, thus removing everything
     from the <parameter>offset</parameter> to the end of the array.
    </para>
   </listitem>
   <listitem>
    <para>
     The <parameter>args</parameter> argument of <function>vsprintf</function>,
     <function>vfprintf</function>, and <function>vprintf</function> must now be an array. Previously
     any type was accepted.
    </para>
   </listitem>
   <listitem>
    <para>
     The <literal>'salt'</literal> option of <function>password_hash</function> is no longer
     supported. If the <literal>'salt'</literal> option is used a warning is generated, the provided
     salt is ignored, and a generated salt is used instead.
    </para>
   </listitem>
   <listitem>
    <para>
     The <function>quotemeta</function> function will now return an empty string if an empty string
     was passed. Previously &false; was returned.
    </para>
   </listitem>
   <listitem>
    <para>
     The following functions have been removed:
    </para>
    <para>
     <simplelist>
      <member><function>hebrevc</function></member>
      <member><function>convert_cyr_string</function></member>
      <member><function>money_format</function></member>
      <member><function>ezmlm_hash</function></member>
      <member><function>restore_include_path</function></member>
      <member><function>get_magic_quotes_gpc</function></member>
      <member><function>get_magic_quotes_runtime</function></member>
      <member><function>fgetss</function></member>
     </simplelist>
    </para>
   </listitem>
   <listitem>
    <para>
     <constant>FILTER_SANITIZE_MAGIC_QUOTES</constant> has been removed.
    </para>
   </listitem>
   <listitem>
    <para>
     Calling <function>implode</function> with parameters in a reverse order <code>($pieces,
     $glue)</code> is no longer supported.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>parse_url</function> will now distinguish absent and empty queries and fragments:
    </para>
    <para>
     <simplelist>
      <member><code>http://example.com/foo → query = null, fragment = null</code></member>
      <member><code>http://example.com/foo? → query = "",   fragment = null</code></member>
      <member><code>http://example.com/foo# → query = null, fragment = ""</code></member>
      <member><code>http://example.com/foo?# → query = "",   fragment = ""</code></member>
     </simplelist>
      Previously all cases resulted in query and fragment being &null;.
    </para>
   </listitem>
   <listitem>
    <para>
     <function>var_dump</function> and <function>debug_zval_dump</function> will now print
     floating-point numbers using <link linkend="ini.serialize-precision">serialize_precision</link>
     rather than <link linkend="ini.precision">precision</link>. In a default configuration, this
     means that floating-point numbers are now printed with full accuracy by these debugging
     functions.
    </para>
   </listitem>
   <listitem>
    <para>
     If the array returned by <link linkend="object.sleep">__sleep()</link> contains non-existing
     properties, these are now silently ignored. Previously, such properties would have been
     serialized as if they had the value &null;.
    </para>
   </listitem>
   <listitem>
    <para>
     The default locale on startup is now always <literal>"C"</literal>. No locales are inherited from
     the environment by default. Previously, <constant>LC_ALL</constant> was set to
     <literal>"C"</literal>, while <constant>LC_CTYPE</constant> was inherited from the environment.
     However, some functions did not respect the inherited locale without an explicit
     <function>setlocale</function> call. An explicit <function>setlocale</function> call is now
     always required if a locale component should be changed from the default.
    </para>
   </listitem>
   <listitem>
    <para>
     The deprecated DES fallback in <function>crypt</function> has been removed. If an unknown salt
     format is passed to <function>crypt</function>, the function will fail with <literal>*0</literal>
     instead of falling back to a weak DES hash now.
    </para>
   </listitem>
   <listitem>
    <para>
     Specifying out of range rounds for SHA256/SHA512 <function>crypt</function> will now fail with
     <literal>*0</literal> instead of clamping to the closest limit. This matches glibc behavior.
    </para>
   </listitem>
   <listitem>
    <para>
     The result of sorting functions may have changed, if the array contains elements that compare as
     equal.
    </para>
   </listitem>
   <listitem>
    <para>
     Any functions accepting callbacks that are not explicitly specified to accept parameters by
     reference will now warn if a callback with reference parameters is used. Examples include
     <function>array_filter</function> and <function>array_reduce</function>. This was already the
     case for most, but not all, functions previously.
    </para>
   </listitem>
   <listitem>
    <para>
     The HTTP stream wrapper as used by functions like <function>file_get_contents</function>
     now advertises HTTP/1.1 rather than HTTP/1.0 by default. This does not change the behavior of the
     client, but may cause servers to respond differently. To retain the old behavior, set the
     <literal>'protocol_version'</literal> stream context option, e.g.
    </para>
    <para>
     <programlisting role="php">
<![CDATA[
<?php
$ctx = stream_context_create(['http' => ['protocol_version' => '1.0']]);
echo file_get_contents('http://example.org', false, $ctx);
?>
]]>
     </programlisting>
    </para>
   </listitem>
   <listitem>
    <para>
     Calling <function>crypt</function> without an explicit salt is no longer supported. If you would
     like to produce a strong hash with an auto-generated salt, use
     <function>password_hash</function> instead.
    </para>
   </listitem>
   <listitem>
    <para>
    <function>substr</function>, <function>mb_substr</function>, <function>iconv_substr</function> and
    <function>grapheme_substr</function> now consistently clamp out-of-bounds offsets to the string
    boundary. Previously, &false; was returned instead of the empty string in some cases.
    </para>
   </listitem>
   <listitem>
    <para>
     On Windows, the program execution functions (<function>proc_open</function>, <function>exec</function>,
     <function>popen</function> etc.) using the shell, now consistently execute <command>%comspec% /s
     /c "$commandline"</command>, which has the same effect as executing
     <command>$commandline</command> (without additional quotes).
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.sysvsem">
  <title>Sysvsem</title>

  <itemizedlist>
   <listitem>
    <para>
     The <parameter>auto_release</parameter> parameter of <function>sem_get</function> was changed to
     accept bool values rather than int.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.tidy">
  <title>Tidy</title>

  <itemizedlist>
   <listitem>
    <para>
     The <parameter>use_include_path</parameter> parameter, which was not used internally, has been
     removed from <function>tidy_repair_string</function>.
    </para>
   </listitem>
   <listitem>
    <para>
     <methodname>tidy::repairString</methodname> and <methodname>tidy::repairFile</methodname> became
     static methods.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.tokenizer">
  <title>Tokenizer</title>

  <itemizedlist>
   <listitem>
    <para>
     <literal>T_COMMENT</literal> tokens will no longer include a trailing newline. The newline will
     instead be part of a following <literal>T_WHITESPACE</literal> token. It should be noted that
     <literal>T_COMMENT</literal> is not always followed by whitespace, it may also be followed by
     <literal>T_CLOSE_TAG</literal> or end-of-file.
    </para>
   </listitem>
   <listitem>
    <para>
     Namespaced names are now represented using the <literal>T_NAME_QUALIFIED</literal>
     (<code>Foo\Bar</code>), <literal>T_NAME_FULLY_QUALIFIED</literal> (<code>\Foo\Bar</code>) and
     <literal>T_NAME_RELATIVE</literal> (<code>namespace\Foo\Bar</code>) tokens.
     <literal>T_NS_SEPARATOR</literal> is only used for standalone namespace separators, and only
     syntactially valid in conjunction with group use declarations.
     <!-- RFC: https://wiki.php.net/rfc/namespaced_names_as_token -->
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.xmlreader">
  <title>XMLReader</title>

  <para>
   <methodname>XMLReader::open</methodname> and <methodname>XMLReader::xml</methodname> are now
   static methods. They can still be called as instance methods, but inheriting classes need to declare them
   as static if they override these methods.
  </para>
 </sect2>

 <sect2 xml:id="migration80.incompatible.xmlrpc">
  <title>XML-RPC</title>

  <para>
   The XML-RPC extension has been moved to PECL and is no longer part of the PHP
   distribution.
  </para>
 </sect2>

 <sect2 xml:id="migration80.incompatible.zip">
  <title>Zip</title>

  <para>
   <constant>ZipArchive::OPSYS_Z_CPM</constant> has been removed (this name was a typo). Use
   <constant>ZipArchive::OPSYS_CPM</constant> instead.
  </para>
 </sect2>

 <sect2 xml:id="migration80.incompatible.zlib">
  <title>Zlib</title>

  <itemizedlist>
   <listitem>
    <para>
     <function>gzgetss</function> has been removed.
    </para>
   </listitem>
   <listitem>
    <para>
     <link linkend="ini.zlib.output-compression">zlib.output_compression</link> is no longer
     automatically disabled for <literal>Content-Type: image/*</literal>.
    </para>
   </listitem>
  </itemizedlist>
 </sect2>

 <sect2 xml:id="migration80.incompatible.php-test-packs">
  <title>Windows PHP Test Packs</title>

  <para>
   The test runner has been renamed from <filename>run-test.php</filename> to
   <filename>run-tests.php</filename>, to match its name in php-src.
  </para>
 </sect2>
</sect1>

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