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[PATCH v2] fetch: support hideRefs to speed up connectivity checks

From
EWEric Wong <e@80x24.org>
Date
Feb 12, 2023, 09:04 UTC
Message-ID
<20230212090426.M558990@dcvr>
In-Reply-To
<20230209122857.M669733@dcvr>

With roughly 800 remotes all fetching into their own refs/remotes/$REMOTE/* island, the connectivity check[1] gets expensive for each fetch on systems which lack sufficient RAM to cache objects.

To do a no-op fetch on one $REMOTE out of hundreds, hideRefs now allows the no-op fetch to take ~30 seconds instead of ~20 minutes on a noisy, RAM-constrained machine (localhost, so no network latency):

   git -c fetch.hideRefs=refs \
	-c fetch.hideRefs='!refs/remotes/$REMOTE/' \
	fetch $REMOTE
[1] `git rev-list --objects --stdin --not --all --quiet --alternate-refs'
Signed-off-by: Eric Wong <e@80x24.org>
---
 Sidenote: I'm curious about the reason $(pwd) is used in some
 places while $PWD seems fine in others, so it doesn't seem to be
 a portability problem.  I chose $PWD since it's faster.
 Documentation/git-rev-parse.txt    | 9 +++++----
 Documentation/rev-list-options.txt | 9 +++++----
 builtin/fetch.c                    | 2 ++
 builtin/rev-list.c                 | 2 +-
 revision.c                         | 3 ++-
 t/t5510-fetch.sh                   | 9 +++++++++
 t/t6018-rev-list-glob.sh           | 2 +-
 t/t6021-rev-list-exclude-hidden.sh | 2 +-
 8 files changed, 26 insertions(+), 12 deletions(-)
diff --git a/Documentation/git-rev-parse.txt b/Documentation/git-rev-parse.txt
index bcd80692870..f26a7591e37 100644
--- a/Documentation/git-rev-parse.txt
+++ b/Documentation/git-rev-parse.txt
@@ -197,10 +197,11 @@ respectively, and they must begin with `refs/` when applied to `--glob`
 or `--all`. If a trailing '/{asterisk}' is intended, it must be given
 explicitly.
 
---exclude-hidden=[receive|uploadpack]::
-	Do not include refs that would be hidden by `git-receive-pack` or
-	`git-upload-pack` by consulting the appropriate `receive.hideRefs` or
-	`uploadpack.hideRefs` configuration along with `transfer.hideRefs` (see
+--exclude-hidden=[fetch|receive|uploadpack]::
+	Do not include refs that would be hidden by `git-fetch`,
+	`git-receive-pack` or `git-upload-pack` by consulting the appropriate
+	`fetch.hideRefs`, `receive.hideRefs` or `uploadpack.hideRefs`
+	configuration along with `transfer.hideRefs` (see
 	linkgit:git-config[1]). This option affects the next pseudo-ref option
 	`--all` or `--glob` and is cleared after processing them.
 
diff --git a/Documentation/rev-list-options.txt b/Documentation/rev-list-options.txt
index ff68e484069..5e7f3c51792 100644
--- a/Documentation/rev-list-options.txt
+++ b/Documentation/rev-list-options.txt
@@ -195,10 +195,11 @@ respectively, and they must begin with `refs/` when applied to `--glob`
 or `--all`. If a trailing '/{asterisk}' is intended, it must be given
 explicitly.
 
---exclude-hidden=[receive|uploadpack]::
-	Do not include refs that would be hidden by `git-receive-pack` or
-	`git-upload-pack` by consulting the appropriate `receive.hideRefs` or
-	`uploadpack.hideRefs` configuration along with `transfer.hideRefs` (see
+--exclude-hidden=[fetch|receive|uploadpack]::
+	Do not include refs that would be hidden by `git-fetch`,
+	`git-receive-pack` or `git-upload-pack` by consulting the appropriate
+	`fetch.hideRefs`, `receive.hideRefs` or `uploadpack.hideRefs`
+	configuration along with `transfer.hideRefs` (see
 	linkgit:git-config[1]). This option affects the next pseudo-ref option
 	`--all` or `--glob` and is cleared after processing them.
 
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 12978622d51..2763dd969bb 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1131,6 +1131,7 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
 	if (!connectivity_checked) {
 		struct check_connected_options opt = CHECK_CONNECTED_INIT;
 
+		opt.exclude_hidden_refs_section = "fetch";
 		rm = ref_map;
 		if (check_connected(iterate_ref_map, &rm, &opt)) {
 			rc = error(_("%s did not send all necessary objects\n"), url);
@@ -1324,6 +1325,7 @@ static int check_exist_and_connected(struct ref *ref_map)
 	}
 
 	opt.quiet = 1;
+	opt.exclude_hidden_refs_section = "fetch";
 	return check_connected(iterate_ref_map, &rm, &opt);
 }
 
diff --git a/builtin/rev-list.c b/builtin/rev-list.c
index d42db0b0cc9..2ab3efd233b 100644
--- a/builtin/rev-list.c
+++ b/builtin/rev-list.c
@@ -38,7 +38,7 @@ static const char rev_list_usage[] =
 "    --tags\n"
 "    --remotes\n"
 "    --stdin\n"
-"    --exclude-hidden=[receive|uploadpack]\n"
+"    --exclude-hidden=[fetch|receive|uploadpack]\n"
 "    --quiet\n"
 "  ordering output:\n"
 "    --topo-order\n"
diff --git a/revision.c b/revision.c
index 21f5f572c22..50940699e4a 100644
--- a/revision.c
+++ b/revision.c
@@ -1574,7 +1574,8 @@ void exclude_hidden_refs(struct ref_exclusions *exclusions, const char *section)
 {
 	struct exclude_hidden_refs_cb cb;
 
-	if (strcmp(section, "receive") && strcmp(section, "uploadpack"))
+	if (strcmp(section, "fetch") && strcmp(section, "receive") &&
+			strcmp(section, "uploadpack"))
 		die(_("unsupported section for hidden refs: %s"), section);
 
 	if (exclusions->hidden_refs_configured)
diff --git a/t/t5510-fetch.sh b/t/t5510-fetch.sh
index c0b745e33b8..287d6c3a8af 100755
--- a/t/t5510-fetch.sh
+++ b/t/t5510-fetch.sh
@@ -1163,6 +1163,15 @@ test_expect_success '--no-show-forced-updates' '
 	)
 '
 
+for section in fetch transfer
+do
+	test_expect_success "$section.hideRefs affects connectivity check" '
+		GIT_TRACE="$PWD"/trace git -c $section.hideRefs=refs -c \
+			$section.hideRefs="!refs/tags/" fetch &&
+		grep "git rev-list .*--exclude-hidden=fetch" trace
+	'
+done
+
 setup_negotiation_tip () {
 	SERVER="$1"
 	URL="$2"
diff --git a/t/t6018-rev-list-glob.sh b/t/t6018-rev-list-glob.sh
index aabf590dda6..67d523d4057 100755
--- a/t/t6018-rev-list-glob.sh
+++ b/t/t6018-rev-list-glob.sh
@@ -187,7 +187,7 @@ test_expect_success 'rev-parse --exclude=ref with --remotes=glob' '
 	compare rev-parse "--exclude=upstream/x --remotes=upstream/*" "upstream/one upstream/two"
 '
 
-for section in receive uploadpack
+for section in fetch receive uploadpack
 do
 	test_expect_success "rev-parse --exclude-hidden=$section with --all" '
 		compare "-c transfer.hideRefs=refs/remotes/ rev-parse" "--branches --tags" "--exclude-hidden=$section --all"
diff --git a/t/t6021-rev-list-exclude-hidden.sh b/t/t6021-rev-list-exclude-hidden.sh
index 32b2b094138..e219ac86738 100755
--- a/t/t6021-rev-list-exclude-hidden.sh
+++ b/t/t6021-rev-list-exclude-hidden.sh
@@ -21,7 +21,7 @@ test_expect_success 'invalid section' '
 	test_cmp expected err
 '
 
-for section in receive uploadpack
+for section in fetch receive uploadpack
 do
 	test_expect_success "$section: passed multiple times" '
 		echo "fatal: --exclude-hidden= passed more than once" >expected &&
Previous: Junio C HamanoNext: Jeff King
Message 7 of 11 in “[RFC] fetch: support hideRefs to speed up connectivity checks”
  1. Eric WongFeb 9, 2023
  2. Jonathan TanFeb 10, 2023
  3. Eric WongFeb 10, 2023
  4. Junio C HamanoFeb 10, 2023
  5. Eric WongFeb 11, 2023
  6. Junio C HamanoFeb 11, 2023
  7. fetch: support hideRefs to speed up connectivity checksEric Wong, Feb 12, 2023
  8. Jeff KingFeb 13, 2023
  9. Philip OakleyFeb 13, 2023
  10. Jeff KingFeb 14, 2023
  11. Eric WongFeb 16, 2023

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