From 483fa7f42d9e7723154aa1baa6e1576cf51cc64b Mon Sep 17 00:00:00 2001 From: Taylor Blau Date: Wed, 31 Mar 2021 21:32:11 -0400 Subject: t/helper/test-bitmap.c: initial commit Add a new 'bitmap' test-tool which can be used to list the commits that have received bitmaps. In theory, a determined tester could run 'git rev-list --test-bitmap ' to check if '' received a bitmap or not, since '--test-bitmap' exits with a non-zero code when it can't find the requested commit. But this is a dubious behavior to rely on, since arguably 'git rev-list' could continue its object walk outside of which commits are covered by bitmaps. This will be used to test the behavior of 'pack.preferBitmapTips', which will be added in the following patch. Signed-off-by: Taylor Blau Signed-off-by: Junio C Hamano --- t/helper/test-bitmap.c | 24 ++++++++++++++++++++++++ t/helper/test-tool.c | 1 + t/helper/test-tool.h | 1 + 3 files changed, 26 insertions(+) create mode 100644 t/helper/test-bitmap.c (limited to 't') diff --git a/t/helper/test-bitmap.c b/t/helper/test-bitmap.c new file mode 100644 index 0000000000..134a1e9d76 --- /dev/null +++ b/t/helper/test-bitmap.c @@ -0,0 +1,24 @@ +#include "test-tool.h" +#include "cache.h" +#include "pack-bitmap.h" + +static int bitmap_list_commits(void) +{ + return test_bitmap_commits(the_repository); +} + +int cmd__bitmap(int argc, const char **argv) +{ + setup_git_directory(); + + if (argc != 2) + goto usage; + + if (!strcmp(argv[1], "list-commits")) + return bitmap_list_commits(); + +usage: + usage("\ttest-tool bitmap list-commits"); + + return -1; +} diff --git a/t/helper/test-tool.c b/t/helper/test-tool.c index f97cd9f48a..a48bd44116 100644 --- a/t/helper/test-tool.c +++ b/t/helper/test-tool.c @@ -15,6 +15,7 @@ struct test_cmd { static struct test_cmd cmds[] = { { "advise", cmd__advise_if_enabled }, + { "bitmap", cmd__bitmap }, { "bloom", cmd__bloom }, { "chmtime", cmd__chmtime }, { "config", cmd__config }, diff --git a/t/helper/test-tool.h b/t/helper/test-tool.h index 28072c0ad5..563fe1b030 100644 --- a/t/helper/test-tool.h +++ b/t/helper/test-tool.h @@ -5,6 +5,7 @@ #include "git-compat-util.h" int cmd__advise_if_enabled(int argc, const char **argv); +int cmd__bitmap(int argc, const char **argv); int cmd__bloom(int argc, const char **argv); int cmd__chmtime(int argc, const char **argv); int cmd__config(int argc, const char **argv); -- cgit v1.2.3 From 3f267a112820f3bdf6b82362680ea6339f0e5f86 Mon Sep 17 00:00:00 2001 From: Taylor Blau Date: Wed, 31 Mar 2021 21:32:14 -0400 Subject: builtin/pack-objects.c: respect 'pack.preferBitmapTips' When writing a new pack with a bitmap, it is sometimes convenient to indicate some reference prefixes which should receive priority when selecting which commits to receive bitmaps. A truly motivated caller could accomplish this by setting 'pack.islandCore', (since all commits in the core island are similarly marked as preferred) but this requires callers to opt into using delta islands, which they may or may not want to do. Introduce a new multi-valued configuration, 'pack.preferBitmapTips' to allow callers to specify a list of reference prefixes. All references which have a prefix contained in 'pack.preferBitmapTips' will mark their tips as "preferred" in the same way as commits are marked as preferred for selection by 'pack.islandCore'. The choice of the verb "prefer" is intentional: marking the NEEDS_BITMAP flag on an object does *not* guarantee that that object will receive a bitmap. It merely guarantees that that commit will receive a bitmap over any *other* commit in the same window by bitmap_writer_select_commits(). The test this patch adds reflects this quirk, too. It only tests that a commit (which didn't receive bitmaps by default) is selected for bitmaps after changing the value of 'pack.preferBitmapTips' to include it. Other commits may lose their bitmaps as a byproduct of how the selection process works (bitmap_writer_select_commits() ignores the remainder of a window after seeing a commit with the NEEDS_BITMAP flag). This configuration will aide in selecting important references for multi-pack bitmaps, since they do not respect the same pack.islandCore configuration. (They could, but doing so may be confusing, since it is packs--not bitmaps--which are influenced by the delta-islands configuration). In a fork network repository (one which lists all forks of a given repository as remotes), for example, it is useful to set pack.preferBitmapTips to 'refs/remotes//heads' and 'refs/remotes//tags', where '' is an opaque identifier referring to the repository which is at the base of the fork chain. Suggested-by: Jeff King Signed-off-by: Taylor Blau Signed-off-by: Junio C Hamano --- t/t5310-pack-bitmaps.sh | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) (limited to 't') diff --git a/t/t5310-pack-bitmaps.sh b/t/t5310-pack-bitmaps.sh index 40b9f63244..f53efc8229 100755 --- a/t/t5310-pack-bitmaps.sh +++ b/t/t5310-pack-bitmaps.sh @@ -554,4 +554,42 @@ test_expect_success 'fetch with bitmaps can reuse old base' ' ) ' +test_expect_success 'pack.preferBitmapTips' ' + git init repo && + test_when_finished "rm -fr repo" && + ( + cd repo && + + # create enough commits that not all are receive bitmap + # coverage even if they are all at the tip of some reference. + test_commit_bulk --message="%s" 103 && + + git rev-list HEAD >commits.raw && + sort commits && + + git log --format="create refs/tags/%s %H" HEAD >refs && + git update-ref --stdin bitmaps && + + # remember which commits did not receive bitmaps + comm -13 bitmaps commits >before && + test_file_not_empty before && + + # mark the commits which did not receive bitmaps as preferred, + # and generate the bitmap again + perl -pe "s{^}{create refs/tags/include/$. }" bitmaps && + comm -13 bitmaps commits >after && + + ! test_cmp before after + ) +' + test_done -- cgit v1.2.3