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[PATCH v3] fetch: allow adding a filter after initial clone.

From
Xin Li <delphij@google.com>
Date
May 28, 2020, 04:08 UTC
Message-ID
<20200528040812.131224-1-delphij@google.com>
In-Reply-To
<20200528032837.GE56118@google.com>

Retroactively adding filter can be useful for existing shallow clones as they allow users to see earlier change histories without downloading all git objects in a regular --unshallow fetch.

Without this patch, users can make a clone partial by editing the repository configuration to convert the remote into a promisor, like:

  git config core.repositoryFormatVersion 1
  git config extensions.partialClone origin
  git fetch --unshallow --filter=blob:none origin

Since the hard part of making this work is already in place and such edits can be error-prone, teach Git to perform the required configuration change automatically instead.

Instead of bailing out immediately when no promisor is available, make the code perform a more precise check for any potential problems (extensions became special in repository version 1, while it can have any value in version 0, so upgrade should not happen if the repository have an unsupported configuration that would render it invalid if we upgraded).

Signed-off-by: Xin Li <delphij@google.com>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/fetch.c               |  3 ---
 list-objects-filter-options.c |  3 ++-
 repository.h                  |  6 ++++++
 setup.c                       | 29 +++++++++++++++++++++++++++++
 t/t0410-partial-clone.sh      | 22 ++++++++++++++++++++++
 5 files changed, 59 insertions(+), 4 deletions(-)
diff --git a/builtin/fetch.c b/builtin/fetch.c
index b5788c16bf..3347d578ea 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -1790,9 +1790,6 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 	if (depth || deepen_since || deepen_not.nr)
 		deepen = 1;
 
-	if (filter_options.choice && !has_promisor_remote())
-		die("--filter can only be used when extensions.partialClone is set");
-
 	if (all) {
 		if (argc == 1)
 			die(_("fetch --all does not take a repository argument"));
diff --git a/list-objects-filter-options.c b/list-objects-filter-options.c
index 256bcfbdfe..3553ad7b0a 100644
--- a/list-objects-filter-options.c
+++ b/list-objects-filter-options.c
@@ -326,7 +326,8 @@ void partial_clone_register(
 
 	/* Check if it is already registered */
 	if (!promisor_remote_find(remote)) {
-		git_config_set("core.repositoryformatversion", "1");
+		if (upgrade_repository_format(1) < 0)
+			die(_("unable to upgrade repository format to support partial clone"));
 
 		/* Add promisor config for the remote */
 		cfg_name = xstrfmt("remote.%s.promisor", remote);
diff --git a/repository.h b/repository.h
index 6534fbb7b3..40cc12c7cf 100644
--- a/repository.h
+++ b/repository.h
@@ -196,4 +196,10 @@ void repo_update_index_if_able(struct repository *, struct lock_file *);
 
 void prepare_repo_settings(struct repository *r);
 
+/*
+ * Return 1 if upgrade repository format to target_version succeeded,
+ * 0 if no upgrade is necessary; returns -1 when upgrade is not possible.
+ */
+int upgrade_repository_format(int target_version);
+
 #endif /* REPOSITORY_H */
diff --git a/setup.c b/setup.c
index 65fe5ecefb..123d3d3433 100644
--- a/setup.c
+++ b/setup.c
@@ -538,6 +538,35 @@ static int check_repository_format_gently(const char *gitdir, struct repository_
 	return 0;
 }
 
+int upgrade_repository_format(int target_version)
+{
+	struct strbuf sb = STRBUF_INIT;
+	struct strbuf err = STRBUF_INIT;
+	struct strbuf repo_version = STRBUF_INIT;
+	struct repository_format repo_fmt = REPOSITORY_FORMAT_INIT;
+
+	strbuf_git_common_path(&sb, the_repository, "config");
+	read_repository_format(&repo_fmt, sb.buf);
+	strbuf_release(&sb);
+
+	if (repo_fmt.version >= target_version)
+		return 0;
+
+	repo_fmt.version = target_version;
+
+	if (verify_repository_format(&repo_fmt, &err) < 0) {
+		warning("unable to upgrade repository format to %d: %s",
+		    target_version, err.buf);
+		strbuf_release(&err);
+		return -1;
+	}
+
+	strbuf_addf(&repo_version, "%d", target_version);
+	git_config_set("core.repositoryformatversion", repo_version.buf);
+	strbuf_release(&repo_version);
+	return 1;
+}
+
 static void init_repository_format(struct repository_format *format)
 {
 	const struct repository_format fresh = REPOSITORY_FORMAT_INIT;
diff --git a/t/t0410-partial-clone.sh b/t/t0410-partial-clone.sh
index a3988bd4b8..d580488330 100755
--- a/t/t0410-partial-clone.sh
+++ b/t/t0410-partial-clone.sh
@@ -30,6 +30,28 @@ test_expect_success 'extensions.partialclone without filter' '
 	git -C client fetch origin
 '
 
+test_expect_success 'convert shallow clone to partial clone' '
+	rm -fr server client &&
+	test_create_repo server &&
+	test_commit -C server my_commit 1 &&
+	test_commit -C server my_commit2 1 &&
+	git clone --depth=1 "file://$(pwd)/server" client &&
+	git -C client fetch --unshallow --filter="blob:none" &&
+	test_cmp_config -C client true remote.origin.promisor &&
+	test_cmp_config -C client blob:none remote.origin.partialclonefilter &&
+	test_cmp_config -C client 1 core.repositoryformatversion
+'
+
+test_expect_success 'convert shallow clone to partial clone must fail with invalid extension' '
+	rm -fr server client &&
+	test_create_repo server &&
+	test_commit -C server my_commit 1 &&
+	test_commit -C server my_commit2 1 &&
+	git clone --depth=1 "file://$(pwd)/server" client &&
+	git -C client config extensions.sandwidth true &&
+	test_must_fail git -C client fetch --unshallow --filter="blob:none"
+'
+
 test_expect_success 'missing reflog object, but promised by a commit, passes fsck' '
 	rm -rf repo &&
 	test_create_repo repo &&
-- 
2.27.0.rc0.183.gde8f92d652-goog
Previous: Jonathan NiederNext: Junio C Hamano
Message 10 of 30 in “fetch: allow adding a filter after initial clone.”
  1. fetch: allow adding a filter after initial clone.Xin Li, May 13, 2020
  2. Junio C HamanoMay 13, 2020
  3. Xin LiMay 13, 2020
  4. Junio C HamanoMay 13, 2020
  5. Junio C HamanoMay 13, 2020
  6. brian m. carlsonMay 13, 2020
  7. 0/1 fetch: allow adding a filter after initial cloneXin Li, May 28, 2020
  8. 1/1 fetch: allow adding a filter after initial clone.Xin Li, May 28, 2020
  9. Jonathan NiederMay 28, 2020
  10. fetch: allow adding a filter after initial clone.Xin Li, May 28, 2020
  11. Junio C HamanoMay 28, 2020
  12. Jonathan NiederMay 28, 2020
  13. Xin LiMay 28, 2020
  14. Jonathan NiederMay 28, 2020
  15. fetch: allow adding a filter after initial clone.Xin Li, May 29, 2020
  16. Junio C HamanoMay 29, 2020
  17. Junio C HamanoMay 29, 2020
  18. Jonathan NiederMay 29, 2020
  19. fetch: allow adding a filter after initial cloneXin Li, May 29, 2020
  20. Xin LiMay 29, 2020
  21. Junio C HamanoMay 29, 2020
  22. 0/4 fetch: allow adding a filter after initial cloneXin Li, Jun 5, 2020
  23. 1/4 repository: add a helper function to perform repository format upgradeXin Li, Jun 5, 2020
  24. Junio C HamanoJun 5, 2020
  25. 2/4 fetch: allow adding a filter after initial cloneXin Li, Jun 5, 2020
  26. Junio C HamanoJun 5, 2020
  27. 3/4 sparse-checkout: upgrade repository to version 1 when enabling extensionXin Li, Jun 5, 2020
  28. Junio C HamanoJun 5, 2020
  29. 4/4 check_repository_format_gently(): refuse extensions for old repositoriesXin Li, Jun 5, 2020
  30. Junio C HamanoJun 8, 2020

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