@matheusbsbs / matheus-bagliano / commits / cd13762d8f

fast-export: when using paths, avoid corrupt stream with non-existent mark

If file paths are specified to fast-export and multiple refs point to a commit that does not touch any of the relevant file paths, then fast-export can hit problems. fast-export has a list of additional refs that it needs to explicitly set after exporting all blobs and commits, and when it tries to get_object_mark() on the relevant commit, it can get a mark of 0, i.e. "not found", because the commit in question did not touch the relevant paths and thus was not exported. Trying to import a stream with a mark corresponding to an unexported object will cause fast-import to crash. Avoid this problem by taking the commit the ref points to and finding an ancestor of it that was exported, and make the ref point to that commit instead. Signed-off-by: Elijah Newren <newren@gmail.com> Acked-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Elijah Newren committed Nov 15, 2018 at 23:59 UTC cd13762d8f837b6339b7d9f3090c0de44d3e01aa
2 files changed +32 -1
builtin/fast-export.c
+12 -1
@@ -901,7 +901,18 @@ static void handle_tags_and_duplicates(void)
901 if (anonymize)
902 name = anonymize_refname(name);
903 /* create refs pointing to already seen commits */
904 - commit = (struct commit *)object;
904 + commit = rewrite_commit((struct commit *)object);
905 + if (!commit) {
906 + /*
907 + * Neither this object nor any of its
908 + * ancestors touch any relevant paths, so
909 + * it has been filtered to nothing. Delete
910 + * it.
911 + */
912 + printf("reset %s\nfrom %s\n\n",
913 + name, oid_to_hex(&null_oid));
914 + continue;
915 + }
916 printf("reset %s\nfrom :%d\n\n", name,
917 get_object_mark(&commit->object));
918 show_progress();
t/t9350-fast-export.sh
+20
@@ -382,6 +382,26 @@ test_expect_success 'path limiting with import-marks does not lose unmodified fi
382 grep file0 actual
383 '
384
385 +test_expect_success 'avoid corrupt stream with non-existent mark' '
386 + test_create_repo avoid_non_existent_mark &&
387 + (
388 + cd avoid_non_existent_mark &&
389 +
390 + test_commit important-path &&
391 +
392 + test_commit ignored &&
393 +
394 + git branch A &&
395 + git branch B &&
396 +
397 + echo foo >>important-path.t &&
398 + git add important-path.t &&
399 + test_commit more changes &&
400 +
401 + git fast-export --all -- important-path.t | git fast-import --force
402 + )
403 +'
404 +
405 test_expect_success 'full-tree re-shows unmodified files' '
406 git checkout -f simple &&
407 git fast-export --full-tree simple >actual &&