From 4f3644056ad2b4c46ed0bcce72f5a1eb5b92bd7f Mon Sep 17 00:00:00 2001 From: Taylor Blau Date: Wed, 9 Sep 2020 11:22:44 -0400 Subject: [PATCH] commit-graph: introduce 'get_bloom_filter_settings()' Many places in the code often need a pointer to the commit-graph's 'struct bloom_filter_settings', in which case they often take the value from the top-most commit-graph. In the non-split case, this works as expected. In the split case, however, things get a little tricky. Not all layers in a chain of incremental commit-graphs are required to themselves have Bloom data, and so whether or not some part of the code uses Bloom filters depends entirely on whether or not the top-most level of the commit-graph chain has Bloom filters. This has been the behavior since Bloom filters were introduced, and has been codified into the tests since a759bfa9ee (t4216: add end to end tests for git log with Bloom filters, 2020-04-06). In fact, t4216.130 requires that Bloom filters are not used in exactly the case described earlier. There is no reason that this needs to be the case, since it is perfectly valid for commits in an earlier layer to have Bloom filters when commits in a newer layer do not. Since Bloom settings are guaranteed in practice to be the same for any layer in a chain that has Bloom data, it is sufficient to traverse the '->base_graph' pointer until either (1) a non-null 'struct bloom_filter_settings *' is found, or (2) until we are at the root of the commit-graph chain. Introduce a 'get_bloom_filter_settings()' function that does just this, and use it instead of purely dereferencing the top-most graph's '->bloom_filter_settings' pointer. While we're at it, add an additional test in t5324 to guard against code in the commit-graph writing machinery that doesn't correctly handle a NULL 'struct bloom_filter *'. Co-authored-by: Derrick Stolee Signed-off-by: Taylor Blau Signed-off-by: Junio C Hamano --- blame.c | 6 ++++-- bloom.c | 6 +++--- commit-graph.c | 11 +++++++++++ commit-graph.h | 2 ++ revision.c | 5 +---- t/t4216-log-bloom.sh | 9 ++++++--- t/t5324-split-commit-graph.sh | 13 +++++++++++++ 7 files changed, 40 insertions(+), 12 deletions(-) diff --git a/blame.c b/blame.c index 82fa16d658..3e5f8787bc 100644 --- a/blame.c +++ b/blame.c @@ -2891,16 +2891,18 @@ void setup_blame_bloom_data(struct blame_scoreboard *sb, const char *path) { struct blame_bloom_data *bd; + struct bloom_filter_settings *bs; if (!sb->repo->objects->commit_graph) return; - if (!sb->repo->objects->commit_graph->bloom_filter_settings) + bs = get_bloom_filter_settings(sb->repo); + if (!bs) return; bd = xmalloc(sizeof(struct blame_bloom_data)); - bd->settings = sb->repo->objects->commit_graph->bloom_filter_settings; + bd->settings = bs; bd->alloc = 4; bd->nr = 0; diff --git a/bloom.c b/bloom.c index 1a573226e7..cd9380ac62 100644 --- a/bloom.c +++ b/bloom.c @@ -38,7 +38,7 @@ static int load_bloom_filter_from_graph(struct commit_graph *g, while (graph_pos < g->num_commits_in_base) g = g->base_graph; - /* The commit graph commit 'c' lives in doesn't carry bloom filters. */ + /* The commit graph commit 'c' lives in doesn't carry Bloom filters. */ if (!g->chunk_bloom_indexes) return 0; @@ -195,8 +195,8 @@ struct bloom_filter *get_bloom_filter(struct repository *r, if (!filter->data) { load_commit_graph_info(r, c); if (commit_graph_position(c) != COMMIT_NOT_FROM_GRAPH && - r->objects->commit_graph->chunk_bloom_indexes) - load_bloom_filter_from_graph(r->objects->commit_graph, filter, c); + load_bloom_filter_from_graph(r->objects->commit_graph, filter, c)) + return filter; } if (filter->data) diff --git a/commit-graph.c b/commit-graph.c index e51c91dd5b..d4b06811be 100644 --- a/commit-graph.c +++ b/commit-graph.c @@ -660,6 +660,17 @@ int generation_numbers_enabled(struct repository *r) return !!first_generation; } +struct bloom_filter_settings *get_bloom_filter_settings(struct repository *r) +{ + struct commit_graph *g = r->objects->commit_graph; + while (g) { + if (g->bloom_filter_settings) + return g->bloom_filter_settings; + g = g->base_graph; + } + return NULL; +} + static void close_commit_graph_one(struct commit_graph *g) { if (!g) diff --git a/commit-graph.h b/commit-graph.h index 09a97030dc..0677dd1031 100644 --- a/commit-graph.h +++ b/commit-graph.h @@ -87,6 +87,8 @@ struct commit_graph *parse_commit_graph(void *graph_map, size_t graph_size); */ int generation_numbers_enabled(struct repository *r); +struct bloom_filter_settings *get_bloom_filter_settings(struct repository *r); + enum commit_graph_write_flags { COMMIT_GRAPH_WRITE_APPEND = (1 << 0), COMMIT_GRAPH_WRITE_PROGRESS = (1 << 1), diff --git a/revision.c b/revision.c index 6de29cdf7a..c45ed1076e 100644 --- a/revision.c +++ b/revision.c @@ -681,10 +681,7 @@ static void prepare_to_use_bloom_filter(struct rev_info *revs) repo_parse_commit(revs->repo, revs->commits->item); - if (!revs->repo->objects->commit_graph) - return; - - revs->bloom_filter_settings = revs->repo->objects->commit_graph->bloom_filter_settings; + revs->bloom_filter_settings = get_bloom_filter_settings(revs->repo); if (!revs->bloom_filter_settings) return; diff --git a/t/t4216-log-bloom.sh b/t/t4216-log-bloom.sh index c21cc160f3..c9f9bdf1ba 100755 --- a/t/t4216-log-bloom.sh +++ b/t/t4216-log-bloom.sh @@ -60,7 +60,7 @@ setup () { test_bloom_filters_used () { log_args=$1 - bloom_trace_prefix="statistics:{\"filter_not_present\":0,\"maybe\"" + bloom_trace_prefix="statistics:{\"filter_not_present\":${2:-0},\"maybe\"" setup "$log_args" && grep -q "$bloom_trace_prefix" "$TRASH_DIRECTORY/trace.perf" && test_cmp log_wo_bloom log_w_bloom && @@ -134,8 +134,11 @@ test_expect_success 'setup - add commit-graph to the chain without Bloom filters test_line_count = 2 .git/objects/info/commit-graphs/commit-graph-chain ' -test_expect_success 'Do not use Bloom filters if the latest graph does not have Bloom filters.' ' - test_bloom_filters_not_used "-- A/B" +test_expect_success 'use Bloom filters even if the latest graph does not have Bloom filters' ' + # Ensure that the number of empty filters is equal to the number of + # filters in the latest graph layer to prove that they are loaded (and + # ignored). + test_bloom_filters_used "-- A/B" 3 ' test_expect_success 'setup - add commit-graph to the chain with Bloom filters' ' diff --git a/t/t5324-split-commit-graph.sh b/t/t5324-split-commit-graph.sh index 9b850ea907..5bdfd53ef9 100755 --- a/t/t5324-split-commit-graph.sh +++ b/t/t5324-split-commit-graph.sh @@ -425,4 +425,17 @@ done <<\EOF 0600 -r-------- EOF +test_expect_success '--split=replace with partial Bloom data' ' + rm -rf $graphdir $infodir/commit-graph && + git reset --hard commits/3 && + git rev-list -1 HEAD~2 >a && + git rev-list -1 HEAD~1 >b && + git commit-graph write --split=no-merge --stdin-commits --changed-paths graph-files && + test_line_count = 1 graph-files && + verify_chain_files_exist $graphdir +' + test_done