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[PATCH 05/30] repository: wire ref extensions to ref backends

From
Derrick Stolee via GitGitGadget <gitgitgadget@gmail.com>
Date
Nov 7, 2022, 18:35 UTC
Message-ID
<3121334256d8ab9afb2922a389ec22f9faaa08cf.1667846164.git.gitgitgadget@gmail.com>
In-Reply-To
<pull.1408.git.1667846164.gitgitgadget@gmail.com>
From: Derrick Stolee <derrickstolee@github.com>

The previous change introduced the extensions.refFormat config option. It is a multi-valued config option that currently understands "files" and "packed", with both values assumed by default. If any value is provided explicitly, this default is ignored and the provided settings are used instead.

The multi-valued nature of this extension presents a way to allow a user to specify that they never want a packed-refs file (only use "files") or that they never want loose reference files (only use "packed"). However, that functionality is not currently connected.

Before actually modifying the files backend to understand these extension settings, do the basic wiring that connects the extensions.refFormat parsing to the creation of the ref backend. A future change will actually change the ref backend initialization based on these settings, but this communication of the extension is sufficiently complicated to be worth an isolated change.

For now, also forbid the setting of only "packed". This is done by redirecting the choice of backend to the packed backend when that selection is made. A later change will make the "files"-only extension value ignore the packed backend.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
---
 cache.h                |  2 ++
 refs.c                 | 22 ++++++++++++++++++++--
 refs/files-backend.c   |  2 +-
 refs/refs-internal.h   |  3 +++
 repository.c           |  2 ++
 repository.h           |  6 ++++++
 setup.c                | 18 +++++++++++++++++-
 t/t3212-ref-formats.sh | 12 ++++++++++++
 8 files changed, 63 insertions(+), 4 deletions(-)
diff --git a/cache.h b/cache.h
index 26ed03bd6de..13e9c251ac3 100644
--- a/cache.h
+++ b/cache.h
@@ -1155,6 +1155,8 @@ struct repository_format {
 	int hash_algo;
 	int sparse_index;
 	char *work_tree;
+	int ref_format_count;
+	enum ref_format_flags ref_format;
 	struct string_list unknown_extensions;
 	struct string_list v1_only_extensions;
 };
diff --git a/refs.c b/refs.c
index 1491ae937eb..21441ddb162 100644
--- a/refs.c
+++ b/refs.c
@@ -1982,6 +1982,15 @@ static struct ref_store *lookup_ref_store_map(struct hashmap *map,
 	return entry ? entry->refs : NULL;
 }
 
+static int add_ref_format_flags(enum ref_format_flags flags, int caps) {
+	if (flags & REF_FORMAT_FILES)
+		caps |= REF_STORE_FORMAT_FILES;
+	if (flags & REF_FORMAT_PACKED)
+		caps |= REF_STORE_FORMAT_PACKED;
+
+	return caps;
+}
+
 /*
  * Create, record, and return a ref_store instance for the specified
  * gitdir.
@@ -1991,9 +2000,17 @@ static struct ref_store *ref_store_init(struct repository *repo,
 					unsigned int flags)
 {
 	const char *be_name = "files";
-	struct ref_storage_be *be = find_ref_storage_backend(be_name);
+	struct ref_storage_be *be;
 	struct ref_store *refs;
 
+	flags = add_ref_format_flags(repo->ref_format, flags);
+
+	if (!(flags & REF_STORE_FORMAT_FILES) &&
+	    (flags & REF_STORE_FORMAT_PACKED))
+		be_name = "packed";
+
+	be = find_ref_storage_backend(be_name);
+
 	if (!be)
 		BUG("reference backend %s is unknown", be_name);
 
@@ -2009,7 +2026,8 @@ struct ref_store *get_main_ref_store(struct repository *r)
 	if (!r->gitdir)
 		BUG("attempting to get main_ref_store outside of repository");
 
-	r->refs_private = ref_store_init(r, r->gitdir, REF_STORE_ALL_CAPS);
+	r->refs_private = ref_store_init(r, r->gitdir,
+					 REF_STORE_ALL_CAPS);
 	r->refs_private = maybe_debug_wrap_ref_store(r->gitdir, r->refs_private);
 	return r->refs_private;
 }
diff --git a/refs/files-backend.c b/refs/files-backend.c
index b89954355de..db6c8e434c6 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -3274,7 +3274,7 @@ static int files_init_db(struct ref_store *ref_store, struct strbuf *err UNUSED)
 }
 
 struct ref_storage_be refs_be_files = {
-	.next = NULL,
+	.next = &refs_be_packed,
 	.name = "files",
 	.init = files_ref_store_create,
 	.init_db = files_init_db,
diff --git a/refs/refs-internal.h b/refs/refs-internal.h
index 69f93b0e2ac..41520c945e4 100644
--- a/refs/refs-internal.h
+++ b/refs/refs-internal.h
@@ -521,6 +521,9 @@ struct ref_store;
 				 REF_STORE_ODB | \
 				 REF_STORE_MAIN)
 
+#define REF_STORE_FORMAT_FILES		(1 << 8) /* can use loose ref files */
+#define REF_STORE_FORMAT_PACKED		(1 << 9) /* can use packed-refs file */
+
 /*
  * Initialize the ref_store for the specified gitdir. These functions
  * should call base_ref_store_init() to initialize the shared part of
diff --git a/repository.c b/repository.c
index 5d166b692c8..96533fc76be 100644
--- a/repository.c
+++ b/repository.c
@@ -182,6 +182,8 @@ int repo_init(struct repository *repo,
 	repo->repository_format_partial_clone = format.partial_clone;
 	format.partial_clone = NULL;
 
+	repo->ref_format = format.ref_format;
+
 	if (worktree)
 		repo_set_worktree(repo, worktree);
 
diff --git a/repository.h b/repository.h
index 24316ac944e..5cfde4282c5 100644
--- a/repository.h
+++ b/repository.h
@@ -61,6 +61,11 @@ struct repo_path_cache {
 	char *shallow;
 };
 
+enum ref_format_flags {
+	REF_FORMAT_FILES = (1 << 0),
+	REF_FORMAT_PACKED = (1 << 1),
+};
+
 struct repository {
 	/* Environment */
 	/*
@@ -95,6 +100,7 @@ struct repository {
 	 * the ref object.
 	 */
 	struct ref_store *refs_private;
+	enum ref_format_flags ref_format;
 
 	/*
 	 * Contains path to often used file names.
diff --git a/setup.c b/setup.c
index f5eb50c969a..a5e63479558 100644
--- a/setup.c
+++ b/setup.c
@@ -578,9 +578,14 @@ static enum extension_result handle_extension(const char *var,
 		data->hash_algo = format;
 		return EXTENSION_OK;
 	} else if (!strcmp(ext, "refformat")) {
-		if (strcmp(value, "files") && strcmp(value, "packed"))
+		if (!strcmp(value, "files"))
+			data->ref_format |= REF_FORMAT_FILES;
+		else if (!strcmp(value, "packed"))
+			data->ref_format |= REF_FORMAT_PACKED;
+		else
 			return error(_("invalid value for '%s': '%s'"),
 				     "extensions.refFormat", value);
+		data->ref_format_count++;
 		return EXTENSION_OK;
 	}
 	return EXTENSION_UNKNOWN;
@@ -723,6 +728,11 @@ int read_repository_format(struct repository_format *format, const char *path)
 	git_config_from_file(check_repo_format, path, format);
 	if (format->version == -1)
 		clear_repository_format(format);
+
+	/* Set default ref_format if no extensions.refFormat exists. */
+	if (!format->ref_format_count)
+		format->ref_format = REF_FORMAT_FILES | REF_FORMAT_PACKED;
+
 	return format->version;
 }
 
@@ -1425,6 +1435,9 @@ int discover_git_directory(struct strbuf *commondir,
 		candidate.partial_clone;
 	candidate.partial_clone = NULL;
 
+	/* take ownership of candidate.ref_format */
+	the_repository->ref_format = candidate.ref_format;
+
 	clear_repository_format(&candidate);
 	return 0;
 }
@@ -1561,6 +1574,8 @@ const char *setup_git_directory_gently(int *nongit_ok)
 			the_repository->repository_format_partial_clone =
 				repo_fmt.partial_clone;
 			repo_fmt.partial_clone = NULL;
+
+			the_repository->ref_format = repo_fmt.ref_format;
 		}
 	}
 	/*
@@ -1650,6 +1665,7 @@ void check_repository_format(struct repository_format *fmt)
 	repo_set_hash_algo(the_repository, fmt->hash_algo);
 	the_repository->repository_format_partial_clone =
 		xstrdup_or_null(fmt->partial_clone);
+	the_repository->ref_format = fmt->ref_format;
 	clear_repository_format(&repo_fmt);
 }
 
diff --git a/t/t3212-ref-formats.sh b/t/t3212-ref-formats.sh
index bc554e7c701..8c4e70196a0 100755
--- a/t/t3212-ref-formats.sh
+++ b/t/t3212-ref-formats.sh
@@ -24,4 +24,16 @@ test_expect_success 'invalid extensions.refFormat' '
 	grep "invalid value for '\''extensions.refFormat'\'': '\''bogus'\''" err
 '
 
+test_expect_success 'extensions.refFormat=packed only' '
+	git init only-packed &&
+	(
+		cd only-packed &&
+		git config core.repositoryFormatVersion 1 &&
+		git config extensions.refFormat packed &&
+		test_commit A &&
+		test_path_exists .git/packed-refs &&
+		test_path_is_missing .git/refs/tags/A
+	)
+'
+
 test_done

-- 
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Previous: Derrick Stolee via GitGitGadgetNext: Derrick Stolee via GitGitGadget
Message 13 of 56 in “[RFC] extensions.refFormat and packed-refs v2 file format”
  1. 00/30 [RFC] extensions.refFormat and packed-refs v2 file formatDerrick Stolee via GitGitGadget, Nov 7, 2022
  2. 01/30 hashfile: allow skipping the hash functionDerrick Stolee via GitGitGadget, Nov 7, 2022
  3. 02/30 read-cache: add index.computeHash config optionDerrick Stolee via GitGitGadget, Nov 7, 2022
  4. Elijah NewrenNov 11, 2022
  5. Derrick StoleeNov 14, 2022
  6. Ævar Arnfjörð BjarmasonNov 17, 2022
  7. 03/30 extensions: add refFormat extensionDerrick Stolee via GitGitGadget, Nov 7, 2022
  8. Elijah NewrenNov 11, 2022
  9. Derrick StoleeNov 16, 2022
  10. 06/30 refs: allow loose files without packed-refsDerrick Stolee via GitGitGadget, Nov 7, 2022
  11. 07/30 chunk-format: number of chunks is optionalDerrick Stolee via GitGitGadget, Nov 7, 2022
  12. 04/30 config: fix multi-level bulleted listDerrick Stolee via GitGitGadget, Nov 7, 2022
  13. 05/30 repository: wire ref extensions to ref backendsDerrick Stolee via GitGitGadget, Nov 7, 2022
  14. 08/30 chunk-format: document trailing table of contentsDerrick Stolee via GitGitGadget, Nov 7, 2022
  15. 09/30 chunk-format: store chunk offset during writeDerrick Stolee via GitGitGadget, Nov 7, 2022
  16. 11/30 chunk-format: parse trailing table of contentsDerrick Stolee via GitGitGadget, Nov 7, 2022
  17. 10/30 chunk-format: allow trailing table of contentsDerrick Stolee via GitGitGadget, Nov 7, 2022
  18. 13/30 packed-backend: extract add_write_error()Derrick Stolee via GitGitGadget, Nov 7, 2022
  19. 12/30 refs: extract packfile format to new fileDerrick Stolee via GitGitGadget, Nov 7, 2022
  20. 14/30 packed-backend: extract iterator/updates mergeDerrick Stolee via GitGitGadget, Nov 7, 2022
  21. 16/30 config: add config values for packed-refs v2Derrick Stolee via GitGitGadget, Nov 7, 2022
  22. 15/30 packed-backend: create abstraction for writing refsDerrick Stolee via GitGitGadget, Nov 7, 2022
  23. 17/30 packed-backend: create shell of v2 writesDerrick Stolee via GitGitGadget, Nov 7, 2022
  24. 18/30 packed-refs: write file format version 2Derrick Stolee via GitGitGadget, Nov 7, 2022
  25. 19/30 packed-refs: read file format v2Derrick Stolee via GitGitGadget, Nov 7, 2022
  26. 20/30 packed-refs: read optional prefix chunksDerrick Stolee via GitGitGadget, Nov 7, 2022
  27. 21/30 packed-refs: write prefix chunksDerrick Stolee via GitGitGadget, Nov 7, 2022
  28. 22/30 packed-backend: create GIT_TEST_PACKED_REFS_VERSIONDerrick Stolee via GitGitGadget, Nov 7, 2022
  29. 24/30 t5312: allow packed-refs v2 formatDerrick Stolee via GitGitGadget, Nov 7, 2022
  30. 23/30 t1409: test with packed-refs v2Derrick Stolee via GitGitGadget, Nov 7, 2022
  31. 26/30 t3210: require packed-refs v1 for some testsDerrick Stolee via GitGitGadget, Nov 7, 2022
  32. 25/30 t5502: add PACKED_REFS_V1 prerequisiteDerrick Stolee via GitGitGadget, Nov 7, 2022
  33. 27/30 t*: skip packed-refs v2 over http testsDerrick Stolee via GitGitGadget, Nov 7, 2022
  34. 28/30 ci: run GIT_TEST_PACKED_REFS_VERSION=2 in some buildsDerrick Stolee via GitGitGadget, Nov 7, 2022
  35. 29/30 p1401: create performance test for ref operationsDerrick Stolee via GitGitGadget, Nov 7, 2022
  36. 30/30 refs: skip hashing when writing packed-refs v2Derrick Stolee via GitGitGadget, Nov 7, 2022
  37. Derrick StoleeNov 9, 2022
  38. Elijah NewrenNov 11, 2022
  39. Derrick StoleeNov 14, 2022
  40. Elijah NewrenNov 15, 2022
  41. Derrick StoleeNov 16, 2022
  42. Elijah NewrenNov 17, 2022
  43. Junio C HamanoNov 18, 2022
  44. Elijah NewrenNov 19, 2022
  45. Taylor BlauNov 19, 2022
  46. Derrick StoleeNov 30, 2022
  47. Han-Wen NienhuysNov 28, 2022
  48. Derrick StoleeNov 30, 2022
  49. Phillip WoodNov 30, 2022
  50. Taylor BlauNov 30, 2022
  51. Han-Wen NienhuysNov 30, 2022
  52. Sean AllredNov 30, 2022
  53. Derrick StoleeDec 1, 2022
  54. Han-Wen NienhuysDec 2, 2022
  55. Ævar Arnfjörð BjarmasonDec 2, 2022
  56. Junio C HamanoNov 30, 2022

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