Add error handling to the backward incompatible changes.

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@337358 c90b9560-bf6c-de11-be94-00142212c4b1

appendices/migration70/incompatible.xml

@@ -4,6 +4,7 @@
 <sect1 xml:id="migration70.incompatible">
  <title>Backward incompatible changes</title>
 
+ &appendices.migration70.incompatible.error-handling;
  &appendices.migration70.incompatible.variable-handling;
  &appendices.migration70.incompatible.foreach;
  &appendices.migration70.incompatible.integers;

appendices/migration70/incompatible/error-handling.xml

@@ -0,0 +1,62 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- $Revision$ -->
+
+<sect2 xml:id="migration70.incompatible.error-handling">
+ <title>Changes to error and exception handling</title>
+
+ <para>
+  Many fatal and recoverable fatal errors have been converted to exceptions in
+  PHP 7. These error exceptions inherit from the <classname>Error</classname>
+  class, which itself implements the <classname>Throwable</classname>
+  interface, which is now the base interface all exceptions inherit.
+ </para>
+
+ <para>
+  A fuller description of how errors operate in PHP 7 can be found
+  <link linkend="language.errors.php7">on the PHP 7 errors page</link>. This
+  migration guide will merely enumerate the changes that affect backward
+  compatibility.
+ </para>
+
+ <sect3 xml:id="migration70.incompatible.error-handling.constructors">
+  <title>Internal constructors always throw exceptions on failure</title>
+
+  <para>
+   Previously, some internal classes would return &null; or an unusable object
+   when the constructor failed. All internal classes will now throw an
+   <classname>Exception</classname> in this case in the same way that user
+   classes already had to.
+  </para>
+ </sect3>
+
+ <sect3 xml:id="migration70.incompatible.error-handling.parse">
+  <title>Parse errors throw <classname>ParseError</classname></title>
+
+  <para>
+   Parser errors now throw a <classname>ParseError</classname> object. Error
+   handling for <function>eval</function> should now include a &catch; block
+   that can handle this error.
+  </para>
+ </sect3>
+</sect2>
+
+<!-- Keep this comment at the end of the file
+Local variables:
+mode: sgml
+sgml-omittag:t
+sgml-shorttag:t
+sgml-minimize-attributes:nil
+sgml-always-quote-attributes:t
+sgml-indent-step:1
+sgml-indent-data:t
+indent-tabs-mode:nil
+sgml-parent-document:nil
+sgml-default-dtd-file:"~/.phpdoc/manual.ced"
+sgml-exposed-tags:nil
+sgml-local-catalogs:nil
+sgml-local-ecat-files:nil
+End:
+vim600: syn=xml fen fdm=syntax fdl=2 si
+vim: et tw=78 syn=sgml
+vi: ts=1 sw=1
+-->