Remove support for upgrading extensions from "unpackaged" state.

Andres Freund pointed out that allowing non-superusers to run
"CREATE EXTENSION ... FROM unpackaged" has security risks, since
the unpackaged-to-1.0 scripts don't try to verify that the existing
objects they're modifying are what they expect.  Just attaching such
objects to an extension doesn't seem too dangerous, but some of them
do more than that.

We could have resolved this, perhaps, by still requiring superuser
privilege to use the FROM option.  However, it's fair to ask just what
we're accomplishing by continuing to lug the unpackaged-to-1.0 scripts
forward.  None of them have received any real testing since 9.1 days,
so they may not even work anymore (even assuming that one could still
load the previous "loose" object definitions into a v13 database).
And an installation that's trying to go from pre-9.1 to v13 or later
in one jump is going to have worse compatibility problems than whether
there's a trivial way to convert their contrib modules into extension
style.

Hence, let's just drop both those scripts and the core-code support
for "CREATE EXTENSION ... FROM".

Discussion: https://postgr.es/m/20200213233015.r6rnubcvl4egdh5r@alap3.anarazel.de

1 files changed, 3 insertions, 67 deletions

diff --git a/src/backend/commands/extension.c b/src/backend/commands/extension.c
index ddd46f4e2f5..a0db7db411b 100644
--- a/src/backend/commands/extension.c
+++ b/src/backend/commands/extension.c
@@ -1357,7 +1357,6 @@ static ObjectAddress
 CreateExtensionInternal(char *extensionName,
 						char *schemaName,
 						const char *versionName,
-						const char *oldVersionName,
 						bool cascade,
 						List *parents,
 						bool is_create)
@@ -1367,6 +1366,8 @@ CreateExtensionInternal(char *extensionName,
 	Oid			extowner = GetUserId();
 	ExtensionControlFile *pcontrol;
 	ExtensionControlFile *control;
+	char	   *filename;
+	struct stat fst;
 	List	   *updateVersions;
 	List	   *requiredExtensions;
 	List	   *requiredSchemas;
@@ -1401,56 +1402,6 @@ CreateExtensionInternal(char *extensionName,
 	 * does what is needed, we try to find a sequence of update scripts that
 	 * will get us there.
 	 */
-	if (oldVersionName)
-	{
-		/*
-		 * "FROM old_version" was specified, indicating that we're trying to
-		 * update from some unpackaged version of the extension.  Locate a
-		 * series of update scripts that will do it.
-		 */
-		check_valid_version_name(oldVersionName);
-
-		if (strcmp(oldVersionName, versionName) == 0)
-			ereport(ERROR,
-					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-					 errmsg("FROM version must be different from installation target version \"%s\"",
-							versionName)));
-
-		updateVersions = identify_update_path(pcontrol,
-											  oldVersionName,
-											  versionName);
-
-		if (list_length(updateVersions) == 1)
-		{
-			/*
-			 * Simple case where there's just one update script to run. We
-			 * will not need any follow-on update steps.
-			 */
-			Assert(strcmp((char *) linitial(updateVersions), versionName) == 0);
-			updateVersions = NIL;
-		}
-		else
-		{
-			/*
-			 * Multi-step sequence.  We treat this as installing the version
-			 * that is the target of the first script, followed by successive
-			 * updates to the later versions.
-			 */
-			versionName = (char *) linitial(updateVersions);
-			updateVersions = list_delete_first(updateVersions);
-		}
-	}
-	else
-	{
-		/*
-		 * No FROM, so we're installing from scratch.  If there is an install
-		 * script for the desired version, we only need to run that one.
-		 */
-		char	   *filename;
-		struct stat fst;
-
-		oldVersionName = NULL;
-
 		filename = get_extension_script_filename(pcontrol, NULL, versionName);
 		if (stat(filename, &fst) == 0)
 		{
@@ -1484,7 +1435,6 @@ CreateExtensionInternal(char *extensionName,
 			/* Otherwise, install best starting point and then upgrade */
 			versionName = evi_start->name;
 		}
-	}
 
 	/*
 	 * Fetch control parameters for installation target version
@@ -1624,7 +1574,7 @@ CreateExtensionInternal(char *extensionName,
 	 * Execute the installation script file
 	 */
 	execute_extension_script(extensionOid, control,
-							 oldVersionName, versionName,
+							 NULL, versionName,
 							 requiredSchemas,
 							 schemaName, schemaOid);
 
@@ -1691,7 +1641,6 @@ get_required_extension(char *reqExtensionName,
 			addr = CreateExtensionInternal(reqExtensionName,
 										   origSchemaName,
 										   NULL,
-										   NULL,
 										   cascade,
 										   cascade_parents,
 										   is_create);
@@ -1719,11 +1668,9 @@ CreateExtension(ParseState *pstate, CreateExtensionStmt *stmt)
 {
 	DefElem    *d_schema = NULL;
 	DefElem    *d_new_version = NULL;
-	DefElem    *d_old_version = NULL;
 	DefElem    *d_cascade = NULL;
 	char	   *schemaName = NULL;
 	char	   *versionName = NULL;
-	char	   *oldVersionName = NULL;
 	bool		cascade = false;
 	ListCell   *lc;
 
@@ -1787,16 +1734,6 @@ CreateExtension(ParseState *pstate, CreateExtensionStmt *stmt)
 			d_new_version = defel;
 			versionName = defGetString(d_new_version);
 		}
-		else if (strcmp(defel->defname, "old_version") == 0)
-		{
-			if (d_old_version)
-				ereport(ERROR,
-						(errcode(ERRCODE_SYNTAX_ERROR),
-						 errmsg("conflicting or redundant options"),
-						 parser_errposition(pstate, defel->location)));
-			d_old_version = defel;
-			oldVersionName = defGetString(d_old_version);
-		}
 		else if (strcmp(defel->defname, "cascade") == 0)
 		{
 			if (d_cascade)
@@ -1815,7 +1752,6 @@ CreateExtension(ParseState *pstate, CreateExtensionStmt *stmt)
 	return CreateExtensionInternal(stmt->extname,
 								   schemaName,
 								   versionName,
-								   oldVersionName,
 								   cascade,
 								   NIL,
 								   true);