1 files changed, 78 insertions, 3 deletions

diff --git a/src/backend/commands/extension.c b/src/backend/commands/extension.c
index 02ff4a9a7fb..0eabe18335e 100644
--- a/src/backend/commands/extension.c
+++ b/src/backend/commands/extension.c
@@ -90,6 +90,8 @@ typedef struct ExtensionControlFile
 	bool		trusted;		/* allow becoming superuser on the fly? */
 	int			encoding;		/* encoding of the script file, or -1 */
 	List	   *requires;		/* names of prerequisite extensions */
+	List	   *no_relocate;	/* names of prerequisite extensions that
+								 * should not be relocated */
 } ExtensionControlFile;
 
 /*
@@ -606,6 +608,21 @@ parse_extension_control_file(ExtensionControlFile *control,
 								item->name)));
 			}
 		}
+		else if (strcmp(item->name, "no_relocate") == 0)
+		{
+			/* Need a modifiable copy of string */
+			char	   *rawnames = pstrdup(item->value);
+
+			/* Parse string into list of identifiers */
+			if (!SplitIdentifierString(rawnames, ',', &control->no_relocate))
+			{
+				/* syntax error in name list */
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						 errmsg("parameter \"%s\" must be a list of extension names",
+								item->name)));
+			}
+		}
 		else
 			ereport(ERROR,
 					(errcode(ERRCODE_SYNTAX_ERROR),
@@ -845,6 +862,8 @@ extension_is_trusted(ExtensionControlFile *control)
  * Execute the appropriate script file for installing or updating the extension
  *
  * If from_version isn't NULL, it's an update
+ *
+ * Note: requiredSchemas must be one-for-one with the control->requires list
  */
 static void
 execute_extension_script(Oid extensionOid, ExtensionControlFile *control,
@@ -860,6 +879,7 @@ execute_extension_script(Oid extensionOid, ExtensionControlFile *control,
 	int			save_nestlevel;
 	StringInfoData pathbuf;
 	ListCell   *lc;
+	ListCell   *lc2;
 
 	/*
 	 * Enforce superuser-ness if appropriate.  We postpone these checks until
@@ -1031,6 +1051,27 @@ execute_extension_script(Oid extensionOid, ExtensionControlFile *control,
 		}
 
 		/*
+		 * Likewise, substitute required extensions' schema names for
+		 * occurrences of @extschema:extension_name@.
+		 */
+		Assert(list_length(control->requires) == list_length(requiredSchemas));
+		forboth(lc, control->requires, lc2, requiredSchemas)
+		{
+			char	   *reqextname = (char *) lfirst(lc);
+			Oid			reqschema = lfirst_oid(lc2);
+			char	   *schemaName = get_namespace_name(reqschema);
+			const char *qSchemaName = quote_identifier(schemaName);
+			char	   *repltoken;
+
+			repltoken = psprintf("@extschema:%s@", reqextname);
+			t_sql = DirectFunctionCall3Coll(replace_text,
+											C_COLLATION_OID,
+											t_sql,
+											CStringGetTextDatum(repltoken),
+											CStringGetTextDatum(qSchemaName));
+		}
+
+		/*
 		 * If module_pathname was set in the control file, substitute its
 		 * value for occurrences of MODULE_PATHNAME.
 		 */
@@ -2817,9 +2858,43 @@ AlterExtensionNamespace(const char *extensionName, const char *newschema, Oid *o
 		Oid			dep_oldNspOid;
 
 		/*
-		 * Ignore non-membership dependencies.  (Currently, the only other
-		 * case we could see here is a normal dependency from another
-		 * extension.)
+		 * If a dependent extension has a no_relocate request for this
+		 * extension, disallow SET SCHEMA.  (XXX it's a bit ugly to do this in
+		 * the same loop that's actually executing the renames: we may detect
+		 * the error condition only after having expended a fair amount of
+		 * work.  However, the alternative is to do two scans of pg_depend,
+		 * which seems like optimizing for failure cases.  The rename work
+		 * will all roll back cleanly enough if we do fail here.)
+		 */
+		if (pg_depend->deptype == DEPENDENCY_NORMAL &&
+			pg_depend->classid == ExtensionRelationId)
+		{
+			char	   *depextname = get_extension_name(pg_depend->objid);
+			ExtensionControlFile *dcontrol;
+			ListCell   *lc;
+
+			dcontrol = read_extension_control_file(depextname);
+			foreach(lc, dcontrol->no_relocate)
+			{
+				char	   *nrextname = (char *) lfirst(lc);
+
+				if (strcmp(nrextname, NameStr(extForm->extname)) == 0)
+				{
+					ereport(ERROR,
+							(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+							 errmsg("cannot SET SCHEMA of extension \"%s\" because other extensions prevent it",
+									NameStr(extForm->extname)),
+							 errdetail("Extension \"%s\" requests no relocation of extension \"%s\".",
+									   depextname,
+									   NameStr(extForm->extname))));
+				}
+			}
+		}
+
+		/*
+		 * Otherwise, ignore non-membership dependencies.  (Currently, the
+		 * only other case we could see here is a normal dependency from
+		 * another extension.)
 		 */
 		if (pg_depend->deptype != DEPENDENCY_EXTENSION)
 			continue;