backfill: default to grabbing edge blobs too

Commit 302aff0922 (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>
This commit is contained in:
Elijah Newren
2026-04-15 23:58:02 +00:00
committed by Junio C Hamano
parent ef6d3c9474
commit a1ad4a0fca
3 changed files with 119 additions and 8 deletions
+8 -1
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@@ -9,7 +9,7 @@ git-backfill - Download missing objects in a partial clone
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 @@ OPTIONS
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
+7 -1
View File
@@ -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);
+104 -6
View File
@@ -257,11 +257,12 @@ test_expect_success 'backfill with revision range' '
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="$(pwd)/backfill-trace" git -C backfill-revs backfill HEAD~2..HEAD &&
# 30 objects downloaded.
# 36 objects downloaded, 12 still missing
test_trace2_data promisor fetch_count 36 <backfill-trace &&
git -C backfill-revs rev-list --quiet --objects --missing=print HEAD >missing &&
test_line_count = 18 missing
test_line_count = 12 missing
'
test_expect_success 'backfill with revisions over stdin' '
@@ -279,11 +280,12 @@ test_expect_success 'backfill with revisions over stdin' '
^HEAD~2
EOF
git -C backfill-revs backfill --stdin <in &&
GIT_TRACE2_EVENT="$(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_expect_success 'backfill with --since' '
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