backfill: default to grabbing edge blobs too Commit 302aff09223f (backfill: accept revision arguments, 2026-03-26) added support for accepting revision arguments to backfill. This allows users to do things like git backfill --remotes ^v2.3.0 and then run many commands without triggering on-demand downloads of blobs. However, if they have topics based on v2.3.0, they will likely still trigger on-demand downloads. Consider, for example, the command git log -p v2.3.0..topic This would still trigger on-demand blob loadings after the backfill command above, because the commit(s) with A as a parent will need to diff against the blobs in A. In fact, multiple commands need blobs from the lower boundary of the revision range: * git log -p A..B # After backfill A..B * git replay --onto TARGET A..B # After backfill TARGET^! A..B * git checkout A && git merge B # After backfill A...B Add an extra --[no-]include-edges flag to allow grabbing blobs from edge commits. Since the point of backfill is to prevent on-demand blob loading and these are common commands, default to --include-edges. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/git-backfill.adoc b/Documentation/git-backfill.adoc index bf26d76..c0a3b80 100644 --- a/Documentation/git-backfill.adoc +++ b/Documentation/git-backfill.adoc
@@ -9,7 +9,7 @@ SYNOPSIS -------- [synopsis] -git backfill [--min-batch-size=<n>] [--[no-]sparse] [<revision-range>] +git backfill [--min-batch-size=<n>] [--[no-]sparse] [--[no-]include-edges] [<revision-range>] DESCRIPTION ----------- @@ -63,6 +63,13 @@ current sparse-checkout. If the sparse-checkout feature is enabled, then `--sparse` is assumed and can be disabled with `--no-sparse`. +`--include-edges`:: +`--no-include-edges`:: + Include blobs from boundary commits in the backfill. Useful in + preparation for commands like `git log -p A..B` or `git replay + --onto TARGET A..B`, where A..B normally excludes A but you need + the blobs from A as well. `--include-edges` is the default. + `<revision-range>`:: Backfill only blobs reachable from commits in the specified revision range. When no _<revision-range>_ is specified, it
diff --git a/builtin/backfill.c b/builtin/backfill.c index e934d36..7ffab2e 100644 --- a/builtin/backfill.c +++ b/builtin/backfill.c
@@ -26,7 +26,7 @@ #include "path-walk.h" static const char * const builtin_backfill_usage[] = { - N_("git backfill [--min-batch-size=<n>] [--[no-]sparse] [<revision-range>]"), + N_("git backfill [--min-batch-size=<n>] [--[no-]sparse] [--[no-]include-edges] [<revision-range>]"), NULL }; @@ -35,6 +35,7 @@ struct backfill_context { struct oid_array current_batch; size_t min_batch_size; int sparse; + int include_edges; struct rev_info revs; }; @@ -116,6 +117,8 @@ static int do_backfill(struct backfill_context *ctx) /* Walk from HEAD if otherwise unspecified. */ if (!ctx->revs.pending.nr) add_head_to_pending(&ctx->revs); + if (ctx->include_edges) + ctx->revs.edge_hint = 1; info.blobs = 1; info.tags = info.commits = info.trees = 0; @@ -143,12 +146,15 @@ int cmd_backfill(int argc, const char **argv, const char *prefix, struct reposit .min_batch_size = 50000, .sparse = -1, .revs = REV_INFO_INIT, + .include_edges = 1, }; struct option options[] = { OPT_UNSIGNED(0, "min-batch-size", &ctx.min_batch_size, N_("Minimum number of objects to request at a time")), OPT_BOOL(0, "sparse", &ctx.sparse, N_("Restrict the missing objects to the current sparse-checkout")), + OPT_BOOL(0, "include-edges", &ctx.include_edges, + N_("Include blobs from boundary commits in the backfill")), OPT_END(), }; struct repo_config_values *cfg = repo_config_values(the_repository);
diff --git a/t/t5620-backfill.sh b/t/t5620-backfill.sh index f3b5e39..94f35ce 100755 --- a/t/t5620-backfill.sh +++ b/t/t5620-backfill.sh
@@ -257,11 +257,12 @@ git -C backfill-revs rev-list --quiet --objects --missing=print HEAD >missing && test_line_count = 48 missing && - git -C backfill-revs backfill HEAD~2..HEAD && + GIT_TRACE2_EVENT="$(pwd)/backfill-trace" git -C backfill-revs backfill HEAD~2..HEAD && - # 30 objects downloaded. + # 36 objects downloaded, 12 still missing + test_trace2_data promisor fetch_count 36 <backfill-trace && git -C backfill-revs rev-list --quiet --objects --missing=print HEAD >missing && - test_line_count = 18 missing + test_line_count = 12 missing ' test_expect_success 'backfill with revisions over stdin' ' @@ -279,11 +280,12 @@ ^HEAD~2 EOF - git -C backfill-revs backfill --stdin <in && + GIT_TRACE2_EVENT="$(pwd)/backfill-trace" git -C backfill-revs backfill --stdin <in && - # 30 objects downloaded. + # 36 objects downloaded, 12 still missing + test_trace2_data promisor fetch_count 36 <backfill-trace && git -C backfill-revs rev-list --quiet --objects --missing=print HEAD >missing && - test_line_count = 18 missing + test_line_count = 12 missing ' test_expect_success 'backfill with prefix pathspec' ' @@ -398,6 +400,102 @@ test_line_count = 6 missing ' +test_expect_success 'backfill range with include-edges enables fetch-free git-log' ' + git clone --no-checkout --filter=blob:none \ + --single-branch --branch=main \ + "file://$(pwd)/srv.bare" backfill-log && + + # Backfill the range with default include edges. + git -C backfill-log backfill HEAD~2..HEAD && + + # git log -p needs edge blobs for the "before" side of + # diffs. With edge inclusion, all needed blobs are local. + GIT_TRACE2_EVENT="$(pwd)/log-trace" git \ + -C backfill-log log -p HEAD~2..HEAD >log-output && + + # No promisor fetches should have been needed. + ! grep "fetch_count" log-trace +' + +test_expect_success 'backfill range without include edges causes on-demand fetches in git-log' ' + git clone --no-checkout --filter=blob:none \ + --single-branch --branch=main \ + "file://$(pwd)/srv.bare" backfill-log-no-bdy && + + # Backfill WITHOUT include edges -- file.3 v1 blobs are missing. + git -C backfill-log-no-bdy backfill --no-include-edges HEAD~2..HEAD && + + # git log -p HEAD~2..HEAD computes diff of commit 7 against + # commit 6. It needs file.3 v1 (the "before" side), which was + # not backfilled. This triggers on-demand promisor fetches. + GIT_TRACE2_EVENT="$(pwd)/log-no-bdy-trace" git \ + -C backfill-log-no-bdy log -p HEAD~2..HEAD >log-output && + + grep "fetch_count" log-no-bdy-trace +' + +test_expect_success 'backfill range enables fetch-free replay' ' + # Create a repo with a branch to replay. + git init replay-src && + ( + cd replay-src && + git config uploadpack.allowfilter 1 && + git config uploadpack.allowanysha1inwant 1 && + test_commit base && + git checkout -b topic && + test_commit topic-change && + git checkout main && + test_commit main-change + ) && + git clone --bare --filter=blob:none \ + "file://$(pwd)/replay-src" replay-dest.git && + + # Backfill the replay range: --onto main, replaying topic~1..topic. + # For replay, we need TARGET^! plus the range. + main_oid=$(git -C replay-dest.git rev-parse main) && + topic_oid=$(git -C replay-dest.git rev-parse topic) && + base_oid=$(git -C replay-dest.git rev-parse topic~1) && + git -C replay-dest.git backfill \ + "$main_oid^!" "$base_oid..$topic_oid" && + + # Now replay should complete without any promisor fetches. + GIT_TRACE2_EVENT="$(pwd)/replay-trace" git -C replay-dest.git \ + replay --onto main topic~1..topic >replay-out && + + ! grep "fetch_count" replay-trace +' + +test_expect_success 'backfill enables fetch-free merge' ' + # Create a repo with two branches to merge. + git init merge-src && + ( + cd merge-src && + git config uploadpack.allowfilter 1 && + git config uploadpack.allowanysha1inwant 1 && + test_commit merge-base && + git checkout -b side && + test_commit side-change && + git checkout main && + test_commit main-side-change + ) && + git clone --filter=blob:none \ + "file://$(pwd)/merge-src" merge-dest && + + # The clone checked out main, fetching its blobs. + # Backfill the three endpoint commits needed for merge. + main_oid=$(git -C merge-dest rev-parse origin/main) && + side_oid=$(git -C merge-dest rev-parse origin/side) && + mbase=$(git -C merge-dest merge-base origin/main origin/side) && + git -C merge-dest backfill --no-include-edges \ + "$main_oid^!" "$side_oid^!" "$mbase^!" && + + # Merge should complete without promisor fetches. + GIT_TRACE2_EVENT="$(pwd)/merge-trace" git -C merge-dest \ + merge origin/side -m "test merge" && + + ! grep "fetch_count" merge-trace +' + . "$TEST_DIRECTORY"/lib-httpd.sh start_httpd