git-svn: fix fetch with deleted tag

Currently git-svn assumes that two tags created from the same
revision will have the same repo url, so it uses a ref to the
tag without checking that its url matches the current url.

This causes issues when fetching an svn repo where a tag was
created, deleted, and then recreated under the following
circumstances:

- Both tags were copied from the same revision.
- Both tags had the same name.
- Both tags had different repository paths.
- [Optional] Both tags have a file with the same name but
  different content.

When all four conditions are met, a checksum mismatch error
occurs because the content of two files with the same path
differs (see t/t9155--git-svn-fetch-deleted-tag.sh):

    Checksum mismatch: ChangeLog 065854....
    expected: ce771b....
         got: 9563fd....

When only the first three conditions are met, no error occurs
but the tag in git matches the first (deleted) tag instead of
the last (most recent) tag (see
t/t9156-git-svn-fetch-deleted-tag-2.sh).

The fix is to verify that the repo url for the ref matches the
current url.  If the urls do not match, then a "tail" is grown
on the tag name by appending a dash and rechecking the new ref's
repo url until either a matching repo url is found or a new tag
is created.

Signed-off-by: David D. Kilzer <ddkilzer@kilzer.net>
Acked-by: Eric Wong <normalperson@yhbt.net>

1 files changed, 42 insertions, 0 deletions

diff --git a/t/t9155-git-svn-fetch-deleted-tag.sh b/t/t9155-git-svn-fetch-deleted-tag.sh
new file mode 100755
index 0000000..ef0ac87
--- /dev/null
+++ b/t/t9155-git-svn-fetch-deleted-tag.sh
@@ -0,0 +1,42 @@
+#!/bin/sh
+
+test_description='git svn fetch deleted tag'
+
+. ./lib-git-svn.sh
+
+test_expect_success 'setup svn repo' '
+	mkdir -p import/trunk/subdir &&
+	mkdir -p import/branches &&
+	mkdir -p import/tags &&
+	echo "base" >import/trunk/subdir/file &&
+	svn_cmd import -m "import for git svn" import "$svnrepo" &&
+	rm -rf import &&
+
+	svn_cmd mkdir --parents -m "create mybranch directory" "$svnrepo/branches/mybranch" &&
+	svn_cmd cp -m "create branch mybranch" "$svnrepo/trunk" "$svnrepo/branches/mybranch/trunk" &&
+
+	svn_cmd co "$svnrepo/trunk" svn_project &&
+	(cd svn_project &&
+		echo "trunk change" >>subdir/file &&
+		svn_cmd ci -m "trunk change" subdir/file &&
+
+		svn_cmd switch "$svnrepo/branches/mybranch/trunk" &&
+		echo "branch change" >>subdir/file &&
+		svn_cmd ci -m "branch change" subdir/file
+	) &&
+
+	svn_cmd cp -m "create mytag attempt 1" -r5 "$svnrepo/trunk/subdir" "$svnrepo/tags/mytag" &&
+	svn_cmd rm -m "delete mytag attempt 1" "$svnrepo/tags/mytag" &&
+	svn_cmd cp -m "create mytag attempt 2" -r5 "$svnrepo/branches/mybranch/trunk/subdir" "$svnrepo/tags/mytag"
+'
+
+test_expect_success 'fetch deleted tags from same revision with checksum error' '
+	git svn init --stdlayout "$svnrepo" git_project &&
+	cd git_project &&
+	git svn fetch &&
+
+	git diff --exit-code mybranch:trunk/subdir/file tags/mytag:file &&
+	git diff --exit-code master:subdir/file tags/mytag^:file
+'
+
+test_done