pg_upgrade: suppress creation of delete script

Suppress creation of the pg_upgrade delete script when the new data
directory is inside the old data directory.

Reported-by: IRC
Backpatch-through: 9.3, where delete script tests were added

diff --git a/src/bin/pg_upgrade/check.c b/src/bin/pg_upgrade/check.c
index 8c034bca771b6966e473c305f3069ef55abb2d8e..e0cb6750c0f8a446feeaadad81106aade7d5b053 100644 (file)
--- a/src/bin/pg_upgrade/check.c
+++ b/src/bin/pg_upgrade/check.c
@@ -195,9 +195,10 @@ output_completion_banner(char *analyze_script_file_name,
                           deletion_script_file_name);
        else
                pg_log(PG_REPORT,
-                          "Could not create a script to delete the old cluster's data\n"
-                 "files because user-defined tablespaces exist in the old cluster\n"
-               "directory.  The old cluster's contents must be deleted manually.\n");
+                 "Could not create a script to delete the old cluster's data files\n"
+                 "because user-defined tablespaces or the new cluster's data directory\n"
+                 "exist in the old cluster directory.  The old cluster's contents must\n"
+                 "be deleted manually.\n");
 }
 
 
@@ -496,18 +497,35 @@ create_script_for_old_cluster_deletion(char **deletion_script_file_name)
 {
        FILE       *script = NULL;
        int                     tblnum;
-       char            old_cluster_pgdata[MAXPGPATH];
+       char            old_cluster_pgdata[MAXPGPATH], new_cluster_pgdata[MAXPGPATH];
 
        *deletion_script_file_name = psprintf("%sdelete_old_cluster.%s",
                                                                                  SCRIPT_PREFIX, SCRIPT_EXT);
 
+       strlcpy(old_cluster_pgdata, old_cluster.pgdata, MAXPGPATH);
+       canonicalize_path(old_cluster_pgdata);
+
+       strlcpy(new_cluster_pgdata, new_cluster.pgdata, MAXPGPATH);
+       canonicalize_path(new_cluster_pgdata);
+
+       /* Some people put the new data directory inside the old one. */
+       if (path_is_prefix_of_path(old_cluster_pgdata, new_cluster_pgdata))
+       {
+               pg_log(PG_WARNING,
+                  "\nWARNING:  new data directory should not be inside the old data directory, e.g. %s\n", old_cluster_pgdata);
+
+               /* Unlink file in case it is left over from a previous run. */
+               unlink(*deletion_script_file_name);
+               pg_free(*deletion_script_file_name);
+               *deletion_script_file_name = NULL;
+               return;
+       }
+
        /*
         * Some users (oddly) create tablespaces inside the cluster data
         * directory.  We can't create a proper old cluster delete script in that
         * case.
         */
-       strlcpy(old_cluster_pgdata, old_cluster.pgdata, MAXPGPATH);
-       canonicalize_path(old_cluster_pgdata);
        for (tblnum = 0; tblnum < os_info.num_old_tablespaces; tblnum++)
        {
                char            old_tablespace_dir[MAXPGPATH];