Make PG_MODULE_MAGIC required in shared libraries that are loaded into

the server.  Per discussion, there seems no point in a waiting period
before making this required.

doc/src/sgml/xfunc.sgml

@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/xfunc.sgml,v 1.114 2006/05/30 21:21:29 tgl Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/xfunc.sgml,v 1.115 2006/05/31 20:58:09 tgl Exp $ -->
 
  <sect1 id="xfunc">
   <title>User-Defined Functions</title>
@@ -1910,6 +1910,41 @@ concat_text(PG_FUNCTION_ARGS)
        </para>
       </listitem>
 
+      <listitem>
+       <para>
+        To ensure your module is not loaded into an incompatible server,
+        it must include a <quote>magic block</>.  This allows
+        the server to detect obvious incompatibilities, such as a module
+        compiled for a different major version of
+        <productname>PostgreSQL</productname>.  A magic block is required
+        as of <productname>PostgreSQL</productname> 8.2.  To include a magic
+        block, write this in one (and only one) of your module source files,
+        after having included the header <filename>fmgr.h</>:
+       </para>
+
+<programlisting>
+#ifdef PG_MODULE_MAGIC
+PG_MODULE_MAGIC;
+#endif
+</programlisting>
+
+       <para>
+        The <literal>#ifdef</> test can be omitted if your code doesn't
+        need to compile against pre-8.2 <productname>PostgreSQL</productname>
+        releases.
+       </para>
+      </listitem>
+
+      <listitem>
+       <para>
+        Compiling and linking your code so that it can be dynamically
+        loaded into <productname>PostgreSQL</productname> always
+        requires special flags.  See <xref linkend="dfunc"> for a
+        detailed explanation of how to do it for your particular
+        operating system.
+       </para>
+      </listitem>
+
       <listitem>
        <para>
         When allocating memory, use the
@@ -1960,41 +1995,6 @@ concat_text(PG_FUNCTION_ARGS)
         error messages to this effect.
        </para>
       </listitem>
-
-      <listitem>
-       <para>
-        To ensure your module is not loaded into an incompatible server, it
-        is recommended to include a <quote>magic block</>.  This allows
-        the server to detect obvious incompatibilities, such as a module
-        compiled for a different major version of
-        <productname>PostgreSQL</productname>.  It is likely that magic
-        blocks will be required in future releases.  To include a magic
-        block, write this in one (and only one) of your module source files,
-        after having included the header <filename>fmgr.h</>:
-       </para>
-
-<programlisting>
-#ifdef PG_MODULE_MAGIC
-PG_MODULE_MAGIC;
-#endif
-</programlisting>
-
-       <para>
-        The <literal>#ifdef</> test can be omitted if your code doesn't
-        need to compile against pre-8.2 <productname>PostgreSQL</productname>
-        releases.
-       </para>
-      </listitem>
-
-      <listitem>
-       <para>
-        Compiling and linking your code so that it can be dynamically
-        loaded into <productname>PostgreSQL</productname> always
-        requires special flags.  See <xref linkend="dfunc"> for a
-        detailed explanation of how to do it for your particular
-        operating system.
-       </para>
-      </listitem>
      </itemizedlist>
     </para>
    </sect2>

src/backend/utils/fmgr/dfmgr.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/fmgr/dfmgr.c,v 1.84 2006/05/30 21:21:30 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/fmgr/dfmgr.c,v 1.85 2006/05/31 20:58:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -188,14 +188,14 @@ load_external_function(char *filename, char *funcname,
 		}
 		else
 		{
-			/*
-			 * Currently we do not reject modules for not having a
-			 * magic block, it would break every external module in
-			 * existence. At some point though, this will become an ERROR.
-			 */
-			ereport(LOG,
-					(errmsg("library \"%s\" does not have a magic block",
-							fullname)));
+			/* try to unlink library */
+			pg_dlclose(file_scanner->handle);
+			free((char *) file_scanner);
+			/* complain */
+			ereport(ERROR,
+					(errmsg("incompatible library \"%s\": missing magic block",
+							fullname),
+					 errhint("Extension libraries are now required to use the PG_MODULE_MAGIC macro.")));
 		}
 		
 		/* OK to link it into list */

src/include/fmgr.h

@@ -11,7 +11,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/fmgr.h,v 1.44 2006/05/30 21:21:30 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/fmgr.h,v 1.45 2006/05/31 20:58:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -314,14 +314,14 @@ extern int no_such_variable
 /*-------------------------------------------------------------------------
  *		Support for verifying backend compatibility of loaded modules
  *
- * If a loaded module includes the macro call
+ * We require dynamically-loaded modules to include the macro call
  *		PG_MODULE_MAGIC;
- * (put this in only one source file), then we can check for obvious
- * incompatibility, such as being compiled for a different major PostgreSQL
- * version.
+ * so that we can check for obvious incompatibility, such as being compiled
+ * for a different major PostgreSQL version.
  *
  * To compile with versions of PostgreSQL that do not support this,
- * you may put an #ifdef/#endif test around it.
+ * you may put an #ifdef/#endif test around it.  Note that in a multiple-
+ * source-file module, the macro call should only appear once.
  * 
  * The specific items included in the magic block are intended to be ones that
  * are custom-configurable and especially likely to break dynamically loaded

src/tutorial/funcs.c

@@ -1,4 +1,4 @@
-/* $PostgreSQL: pgsql/src/tutorial/funcs.c,v 1.14 2006/03/11 04:38:42 momjian Exp $ */
+/* $PostgreSQL: pgsql/src/tutorial/funcs.c,v 1.15 2006/05/31 20:58:09 tgl Exp $ */
 
 /******************************************************************************
   These are user-defined functions that can be bound to a Postgres backend
@@ -16,6 +16,8 @@
 #include "executor/executor.h"	/* for GetAttributeByName() */
 #include "utils/geo_decls.h"	/* for point type */
 
+PG_MODULE_MAGIC;
+
 
 /* These prototypes just prevent possible warnings from gcc. */