filter-repo: handle locally modified refs vs. automatic fetch of --sdr

Signed-off-by: Elijah Newren <[email protected]>

git-filter-repo

@@ -4368,6 +4368,7 @@ class RepoFilter(object):
     target_working_dir = self._args.target or b'.'
     refs_to_migrate = set(x for x in self._orig_refs
                           if x.startswith(b'refs/remotes/origin/'))
+    refs_to_warn_about = set()
     if refs_to_migrate:
       if self._args.debug:
         print("[DEBUG] Migrating refs/remotes/origin/* -> refs/heads/*")
@@ -4381,8 +4382,10 @@ class RepoFilter(object):
         newref = ref.replace(b'refs/remotes/origin/', b'refs/heads/')
         if newref not in self._orig_refs:
           p.stdin.write(b'create %s %s\n' % (newref, self._orig_refs[ref]))
+          self._orig_refs[newref] = self._orig_refs[ref]
+        elif self._orig_refs[ref] != self._orig_refs[newref]:
+          refs_to_warn_about.add(newref)
         p.stdin.write(b'delete %s %s\n' % (ref, self._orig_refs[ref]))
-        self._orig_refs[newref] = self._orig_refs[ref]
         del self._orig_refs[ref]
       p.stdin.close()
       if p.wait(): # pragma: no cover
@@ -4399,6 +4402,22 @@ class RepoFilter(object):
        not self._args.no_fetch and \
        not self._already_ran and \
        self._config_settings.get(b'remote.origin.mirror', b'false') != b'true':
+
+      if refs_to_warn_about:
+        msg = ("Warning: You have refs modified from upstream:\n             " +
+               "\n            ".join([decode(x) for x in refs_to_warn_about]) +
+               "\n" +
+               "         We want to forcibly fetch from upstream to ensure\n" +
+               "         that all relevent refs are rewritten, but this will\n" +
+               "         discard your local changes before starting the\n" +
+               "         rewrite.  Proceed with fetch (Y/N)?")
+        response = input(msg)
+
+        if response.lower() != 'y':
+          self._args.no_fetch = True
+          # Don't do the fetch, and don't remove the origin remote
+          return
+
       cmd = 'git fetch -q --prune --update-head-ok --refmap "" origin +refs/*:refs/*'
       m = _("NOTICE: Fetching all refs from origin to make sure we rewrite\n"
             "        all history that may reference the sensitive data, via\n"

t/t9393-filter-repo-rerun.sh

@@ -617,6 +617,28 @@ test_expect_success 'sdr: interaction with fetch and notes and stashes' '
 	)
 '
 
+test_expect_success 'sdr: handling local-only changes' '
+	test_create_repo sdr_with_local_only_changes &&
+	(
+		cd sdr_with_local_only_changes &&
+		git fast-import --quiet <$DATA/simple &&
+		git clone "file://$(pwd)" fresh_clone &&
+
+		cd fresh_clone &&
+
+		echo stuff >>fileB &&
+		git commit -m "random changes" fileB &&
+
+		echo n | git filter-repo --sdr --path fileB --force >../output &&
+
+		grep "You have refs modified from upstream" ../output &&
+
+		git log -1 --format=%s fileB >actual &&
+		echo "random changes" >expect &&
+		test_cmp expect actual
+	)
+'
+
 test_expect_success 'lfs: not in use, no files to process' '
 	test_create_repo no_lfs_files_to_process &&
 	(