If the changed-path Bloom filters are relatively stable, then I propose trying to build upon them as a way to discover any deficiencies. Also, it's good to use them when we can. The goal I set out to achieve was to use Bloom filters as much as possible in git blame. I think I have achieved most of that, except I did not integrate it with the -C mode. In that case, the blob-diff computation takes a majority of the computation time, so short-circuiting the tree diff using Bloom filters. Also, it's just really complicated. If someone else thinks there is an easy win there, then please go ahead and give it a try with the extra logic presented here in PATCH 3. While I was playing around with Bloom filters and git blame, I purposefully got it working with some scenarios but not all. Then I tried to trigger a failing build in the blame tests using GIT_TEST_COMMIT_GRAPH=1 and GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS=1. But the tests all succeeded! Examining the data, I see that the commit-graph didn't have the Bloom filter chunks at all. This is because we are not setting the flag to write them in the right spot. The GIT_TEST_COMMIT_GRAPH=1 variable triggers a commit-graph write during git commit, so we need to update the code there instead of just inspecting the variable in git commit-graph write. (This is PATCH 2.) By updating this variable, I saw some test failures in other tests regarding non-exact pathspecs. I fixed these in PATCH 1 so we keep clean builds. I based this change on [1] but it would apply cleanly (and logically) on gs/commit-graph-path-filter Updates in v2: * Added PATCH 3 to write commit-graph files during 'git merge' if GIT_TEST_COMMIT_GRAPH is enabled. * Updated PATCH 1 with the simplification recommended by Taylor. * Fixed the lower-case "bloom" in the commit message. Thanks, -Stolee [1] https://lore.kernel.org/git/pull.601.v2.git.1586437211842.gitgitgadget@xxxxxxxxx/ Derrick Stolee (3): revision: complicated pathspecs disable filters tests: write commit-graph with Bloom filters blame: use changed-path Bloom filters blame.c | 139 ++++++++++++++++++++++++++++++++++++++++++++--- blame.h | 6 ++ builtin/blame.c | 10 ++++ builtin/commit.c | 4 +- builtin/merge.c | 7 ++- commit-graph.c | 14 +++++ commit-graph.h | 9 +++ revision.c | 19 ++++++- 8 files changed, 193 insertions(+), 15 deletions(-) base-commit: f4df00a0dd448edce0e854a97f63598fefe27d27 Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-609%2Fderrickstolee%2Fbloom-blame-v3 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-609/derrickstolee/bloom-blame-v3 Pull-Request: https://github.com/gitgitgadget/git/pull/609 Range-diff vs v2: 1: adc03eee4ac = 1: adc03eee4ac revision: complicated pathspecs disable filters 2: 7e8f1aed113 < -: ----------- commit: write commit-graph with Bloom filters 3: 824f8ad067b ! 2: 4073c8fe42f commit-graph: write commit-graph in more tests @@ Metadata Author: Derrick Stolee <dstolee@xxxxxxxxxxxxx> ## Commit message ## - commit-graph: write commit-graph in more tests + tests: write commit-graph with Bloom filters - The GIT_TEST_COMMIT_GRAPH test environment variable triggers - commit-graph writes during each "git commit" process. To expand - the number of tests that have commits in the commit-graph file, - add a helper method that computes the commit-graph and place + The GIT_TEST_COMMIT_GRAPH environment variable updates the commit- + graph file whenever "git commit" is run, ensuring that we always + have an updated commit-graph throughout the test suite. The + GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS environment variable was + introduced to write the changed-path Bloom filters whenever "git + commit-graph write" is run. However, the GIT_TEST_COMMIT_GRAPH + trick doesn't launch a separate process and instead writes it + directly. + + To expand the number of tests that have commits in the commit-graph + file, add a helper method that computes the commit-graph and place that helper inside "git commit" and "git merge". + In the helper method, check GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS + to ensure we are writing changed-path Bloom filters whenever + possible. + Signed-off-by: Derrick Stolee <dstolee@xxxxxxxxxxxxx> ## builtin/commit.c ## @@ commit-graph.c +void git_test_write_commit_graph_or_die(void) +{ -+ if (git_env_bool(GIT_TEST_COMMIT_GRAPH, 0) && -+ write_commit_graph_reachable(the_repository->objects->odb, 0, NULL)) ++ int flags = 0; ++ if (!git_env_bool(GIT_TEST_COMMIT_GRAPH, 0)) ++ return; ++ ++ if (git_env_bool(GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS, 0)) ++ flags = COMMIT_GRAPH_WRITE_BLOOM_FILTERS; ++ ++ if (write_commit_graph_reachable(the_repository->objects->odb, ++ flags, NULL)) + die("failed to write commit-graph under GIT_TEST_COMMIT_GRAPH"); +} + @@ commit-graph.h #define GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD "GIT_TEST_COMMIT_GRAPH_DIE_ON_LOAD" #define GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS "GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS" ++/* ++ * This method is only used to enhance coverage of the commit-graph ++ * feature in the test suite with the GIT_TEST_COMMIT_GRAPH and ++ * GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS environment variables. Do not ++ * call this method oustide of a builtin, and only if you know what ++ * you are doing! ++ */ +void git_test_write_commit_graph_or_die(void); + struct commit; 4: 4ae196d6355 = 3: 463d6bf5033 blame: use changed-path Bloom filters -- gitgitgadget
