(This series is based on tb/pack-bitmap-traversal-with-boundary due to wanting to modify prepare_repo_settings() in a similar way.) The replace-refs can be ignored via the core.useReplaceRefs=false config setting. This setting is possible to miss in some Git commands if they do not load default config at the appropriate time. See [1] for a recent example of this. [1] https://lore.kernel.org/git/pull.1530.git.1683745654800.gitgitgadget@xxxxxxxxx/ This series aims to avoid this kind of error from happening in the future. The idea is to encapsulate the setting in such a way that we can guarantee that config has been checked before using the in-memory value. Further, we must be careful that some Git commands want to disable replace refs unconditionally, as if GIT_NO_REPLACE_REFS was enabled in the environment. The approach taken here is to split the global into two different sources. First, read_replace_refs is kept (but moved to replace-objects.c scope) and reflects whether or not the feature is permitted by the environment and the current command. Second, a new value is added to repo-settings and this is checked after using prepare_repo_settings() to guarantee the config has been read. This presents a potential behavior change, in that now core.useReplaceRefs is specific to each in-memory repository instead of applying the superproject value to all submodules. I could not find a Git command that has multiple in-memory repositories and follows OIDs to object contents, so I'm not sure how to demonstrate it in a test. Here is the breakdown of the series: * Patch 1 creates disable_replace_refs() to encapsulate the global disabling of the feature. * Patch 2 creates replace_refs_enabled() to check if the feature is enabled (with respect to a given repository). * Patch 3 creates the value in repo-settings as well as ensures that the repo settings have been prepared before accessing the value within replace_refs_enabled(). A test is added to demonstrate how the config value is now scoped on a per-repository basis. Updates in v3 ============= Thanks for the review on v2! * The removal of the global from environment.c is delayed to patch 3 because config.c still assigns the value in patch 2. * The comment for the member in the repo_settings struct is modified for better grammar. Updates in v2 ============= Thanks for the careful review on v1! * disable_replace_refs() now replaces "read_replace_refs = 0" in the exact same line to avoid possible behavior change. * Stale comments, include headers, and commit messages are updated to include the latest status. * Patch 3 contains a test of the repo-scoped value using 'git grep'. Thanks, -Stolee Derrick Stolee (3): repository: create disable_replace_refs() replace-objects: create wrapper around setting repository: create read_replace_refs setting builtin/cat-file.c | 2 +- builtin/commit-graph.c | 2 +- builtin/fsck.c | 2 +- builtin/index-pack.c | 2 +- builtin/pack-objects.c | 2 +- builtin/prune.c | 2 +- builtin/replace.c | 2 +- builtin/unpack-objects.c | 2 +- builtin/upload-pack.c | 2 +- commit-graph.c | 4 +-- config.c | 5 ---- environment.c | 3 +-- git.c | 2 +- log-tree.c | 2 +- replace-object.c | 28 ++++++++++++++++++++- replace-object.h | 30 +++++++++++++++------- repo-settings.c | 1 + repository.h | 9 +++++++ t/t7814-grep-recurse-submodules.sh | 40 ++++++++++++++++++++++++++++++ 19 files changed, 111 insertions(+), 31 deletions(-) base-commit: b0afdce5dab61f224fd66c13768facc36a7f8705 Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1537%2Fderrickstolee%2Freplace-refs-safety-v3 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1537/derrickstolee/replace-refs-safety-v3 Pull-Request: https://github.com/gitgitgadget/git/pull/1537 Range-diff vs v2: 1: 0616fdbf303 = 1: 0616fdbf303 repository: create disable_replace_refs() 2: 0831e7f8b5e ! 2: 4e75a76f5dd replace-objects: create wrapper around setting @@ Commit message set accidentally in other places, wrap it in a replace_refs_enabled() method. - This allows us to remove the global from being recognized outside of - replace-objects.c. + Since we still assign this global in config.c, we are not able to remove + the global scope of this variable and make it a static within + replace-object.c. This will happen in a later change which will also + prevent the variable from being read before it is initialized. - Further, a future change will help prevent the variable from being read - before it is initialized. Centralizing its access is an important first - step. + Centralizing read access to the variable is an important first step. Signed-off-by: Derrick Stolee <derrickstolee@xxxxxxxxxx> @@ commit-graph.c: static struct commit_graph *alloc_commit_graph(void) if (hashmap_get_size(&r->objects->replace_map->map)) return 0; - ## environment.c ## -@@ environment.c: const char *editor_program; - const char *askpass_program; - const char *excludes_file; - enum auto_crlf auto_crlf = AUTO_CRLF_FALSE; --int read_replace_refs = 1; - enum eol core_eol = EOL_UNSET; - int global_conv_flags_eol = CONV_EOL_RNDTRP_WARN; - char *check_roundtrip_encoding = "SHIFT-JIS"; - ## log-tree.c ## @@ log-tree.c: static int add_ref_decoration(const char *refname, const struct object_id *oid, @@ log-tree.c: static int add_ref_decoration(const char *refname, const struct obje &original_oid)) { ## replace-object.c ## -@@ replace-object.c: const struct object_id *do_lookup_replace_object(struct repository *r, - die(_("replace depth too high for object %s"), oid_to_hex(oid)); - } - -+static int read_replace_refs = 1; -+ - void disable_replace_refs(void) +@@ replace-object.c: void disable_replace_refs(void) { read_replace_refs = 0; } @@ replace-object.h: void prepare_replace_object(struct repository *r); const struct object_id *do_lookup_replace_object(struct repository *r, const struct object_id *oid); -+ +/* + * Some commands disable replace-refs unconditionally, and otherwise each + * repository could alter the core.useReplaceRefs config value. 3: 4c7dbeb8c6d ! 3: 8b7c7714c8c repository: create read_replace_refs setting @@ Commit message method, if necessary. This solves the problem of forgetting to check the config, as we will check it before returning this value. + Due to this encapsulation, the global can move to be static within + replace-object.c. + There is an interesting behavior change possible here: we now have a repository-scoped understanding of this config value. Thus, if there was a command that recurses into submodules and might follow replace refs, @@ config.c: static int git_default_core_config(const char *var, const char *value, return platform_core_config(var, value, cb); } + ## environment.c ## +@@ environment.c: const char *editor_program; + const char *askpass_program; + const char *excludes_file; + enum auto_crlf auto_crlf = AUTO_CRLF_FALSE; +-int read_replace_refs = 1; + enum eol core_eol = EOL_UNSET; + int global_conv_flags_eol = CONV_EOL_RNDTRP_WARN; + char *check_roundtrip_encoding = "SHIFT-JIS"; + ## replace-object.c ## @@ replace-object.c: void prepare_replace_object(struct repository *r) * replacement object's name (replaced recursively, if necessary). @@ replace-object.c: void prepare_replace_object(struct repository *r) */ const struct object_id *do_lookup_replace_object(struct repository *r, const struct object_id *oid) +@@ replace-object.c: const struct object_id *do_lookup_replace_object(struct repository *r, + die(_("replace depth too high for object %s"), oid_to_hex(oid)); + } + ++/* ++ * This indicator determines whether replace references should be ++ * respected process-wide, regardless of which repository is being ++ * using at the time. ++ */ ++static int read_replace_refs = 1; ++ + void disable_replace_refs(void) + { + read_replace_refs = 0; @@ replace-object.c: void disable_replace_refs(void) int replace_refs_enabled(struct repository *r) @@ repository.h: struct repo_settings { int pack_use_bitmap_boundary_traversal; + /* -+ * Has this repository have core.useReplaceRefs=true (on by ++ * Does this repository have core.useReplaceRefs=true (on by + * default)? This provides a repository-scoped version of this + * config, though it could be disabled process-wide via some Git + * builtins or the --no-replace-objects option. See -- gitgitgadget
