git/repository.c
Junio C Hamano 40a163f217 Merge branch 'ps/ref-storage-migration'
A new command has been added to migrate a repository that uses the
files backend for its ref storage to use the reftable backend, with
limitations.

* ps/ref-storage-migration:
  builtin/refs: new command to migrate ref storage formats
  refs: implement logic to migrate between ref storage formats
  refs: implement removal of ref storages
  worktree: don't store main worktree twice
  reftable: inline `merged_table_release()`
  refs/files: fix NULL pointer deref when releasing ref store
  refs/files: extract function to iterate through root refs
  refs/files: refactor `add_pseudoref_and_head_entries()`
  refs: allow to skip creation of reflog entries
  refs: pass storage format to `ref_store_init()` explicitly
  refs: convert ref storage format to an enum
  setup: unset ref storage when reinitializing repository version
2024-06-17 15:55:55 -07:00

416 lines
11 KiB
C

#include "git-compat-util.h"
#include "abspath.h"
#include "repository.h"
#include "object-store-ll.h"
#include "config.h"
#include "object.h"
#include "lockfile.h"
#include "path.h"
#include "read-cache-ll.h"
#include "remote.h"
#include "setup.h"
#include "loose.h"
#include "submodule-config.h"
#include "sparse-index.h"
#include "trace2.h"
#include "promisor-remote.h"
#include "refs.h"
/*
* We do not define `USE_THE_REPOSITORY_VARIABLE` in this file because we do
* not want to rely on functions that implicitly use `the_repository`. This
* means that the `extern` declaration of `the_repository` isn't visible here,
* which makes sparse unhappy. We thus declare it here.
*/
extern struct repository *the_repository;
/* The main repository */
static struct repository the_repo;
struct repository *the_repository = &the_repo;
/*
* An escape hatch: if we hit a bug in the production code that fails
* to set an appropriate hash algorithm (most likely to happen when
* running outside a repository), we can tell the user who reported
* the crash to set the environment variable to "sha1" (all lowercase)
* to revert to the historical behaviour of defaulting to SHA-1.
*/
static void set_default_hash_algo(struct repository *repo)
{
const char *hash_name;
int algo;
hash_name = getenv("GIT_TEST_DEFAULT_HASH_ALGO");
if (!hash_name)
return;
algo = hash_algo_by_name(hash_name);
if (algo == GIT_HASH_UNKNOWN)
return;
repo_set_hash_algo(repo, algo);
}
void initialize_repository(struct repository *repo)
{
repo->objects = raw_object_store_new();
repo->remote_state = remote_state_new();
repo->parsed_objects = parsed_object_pool_new();
ALLOC_ARRAY(repo->index, 1);
index_state_init(repo->index, repo);
/*
* When a command runs inside a repository, it learns what
* hash algorithm is in use from the repository, but some
* commands are designed to work outside a repository, yet
* they want to access the_hash_algo, if only for the length
* of the hashed value to see if their input looks like a
* plausible hash value.
*
* We are in the process of identifying such code paths and
* giving them an appropriate default individually; any
* unconverted code paths that try to access the_hash_algo
* will thus fail. The end-users however have an escape hatch
* to set GIT_TEST_DEFAULT_HASH_ALGO environment variable to
* "sha1" to get back the old behaviour of defaulting to SHA-1.
*
* This escape hatch is deliberately kept unadvertised, so
* that they see crashes and we can get a report before
* telling them about it.
*/
if (repo == the_repository)
set_default_hash_algo(repo);
}
static void expand_base_dir(char **out, const char *in,
const char *base_dir, const char *def_in)
{
free(*out);
if (in)
*out = xstrdup(in);
else
*out = xstrfmt("%s/%s", base_dir, def_in);
}
static void repo_set_commondir(struct repository *repo,
const char *commondir)
{
struct strbuf sb = STRBUF_INIT;
free(repo->commondir);
if (commondir) {
repo->different_commondir = 1;
repo->commondir = xstrdup(commondir);
return;
}
repo->different_commondir = get_common_dir_noenv(&sb, repo->gitdir);
repo->commondir = strbuf_detach(&sb, NULL);
}
void repo_set_gitdir(struct repository *repo,
const char *root,
const struct set_gitdir_args *o)
{
const char *gitfile = read_gitfile(root);
/*
* repo->gitdir is saved because the caller could pass "root"
* that also points to repo->gitdir. We want to keep it alive
* until after xstrdup(root). Then we can free it.
*/
char *old_gitdir = repo->gitdir;
repo->gitdir = xstrdup(gitfile ? gitfile : root);
free(old_gitdir);
repo_set_commondir(repo, o->commondir);
if (!repo->objects->odb) {
CALLOC_ARRAY(repo->objects->odb, 1);
repo->objects->odb_tail = &repo->objects->odb->next;
}
expand_base_dir(&repo->objects->odb->path, o->object_dir,
repo->commondir, "objects");
repo->objects->odb->disable_ref_updates = o->disable_ref_updates;
free(repo->objects->alternate_db);
repo->objects->alternate_db = xstrdup_or_null(o->alternate_db);
expand_base_dir(&repo->graft_file, o->graft_file,
repo->commondir, "info/grafts");
expand_base_dir(&repo->index_file, o->index_file,
repo->gitdir, "index");
}
void repo_set_hash_algo(struct repository *repo, int hash_algo)
{
repo->hash_algo = &hash_algos[hash_algo];
}
void repo_set_compat_hash_algo(struct repository *repo, int algo)
{
if (hash_algo_by_ptr(repo->hash_algo) == algo)
BUG("hash_algo and compat_hash_algo match");
repo->compat_hash_algo = algo ? &hash_algos[algo] : NULL;
if (repo->compat_hash_algo)
repo_read_loose_object_map(repo);
}
void repo_set_ref_storage_format(struct repository *repo,
enum ref_storage_format format)
{
repo->ref_storage_format = format;
}
/*
* Attempt to resolve and set the provided 'gitdir' for repository 'repo'.
* Return 0 upon success and a non-zero value upon failure.
*/
static int repo_init_gitdir(struct repository *repo, const char *gitdir)
{
int ret = 0;
int error = 0;
char *abspath = NULL;
const char *resolved_gitdir;
struct set_gitdir_args args = { NULL };
abspath = real_pathdup(gitdir, 0);
if (!abspath) {
ret = -1;
goto out;
}
/* 'gitdir' must reference the gitdir directly */
resolved_gitdir = resolve_gitdir_gently(abspath, &error);
if (!resolved_gitdir) {
ret = -1;
goto out;
}
repo_set_gitdir(repo, resolved_gitdir, &args);
out:
free(abspath);
return ret;
}
void repo_set_worktree(struct repository *repo, const char *path)
{
repo->worktree = real_pathdup(path, 1);
trace2_def_repo(repo);
}
static int read_and_verify_repository_format(struct repository_format *format,
const char *commondir)
{
int ret = 0;
struct strbuf sb = STRBUF_INIT;
strbuf_addf(&sb, "%s/config", commondir);
read_repository_format(format, sb.buf);
strbuf_reset(&sb);
if (verify_repository_format(format, &sb) < 0) {
warning("%s", sb.buf);
ret = -1;
}
strbuf_release(&sb);
return ret;
}
/*
* Initialize 'repo' based on the provided 'gitdir'.
* Return 0 upon success and a non-zero value upon failure.
*/
int repo_init(struct repository *repo,
const char *gitdir,
const char *worktree)
{
struct repository_format format = REPOSITORY_FORMAT_INIT;
memset(repo, 0, sizeof(*repo));
initialize_repository(repo);
if (repo_init_gitdir(repo, gitdir))
goto error;
if (read_and_verify_repository_format(&format, repo->commondir))
goto error;
repo_set_hash_algo(repo, format.hash_algo);
repo_set_compat_hash_algo(repo, format.compat_hash_algo);
repo_set_ref_storage_format(repo, format.ref_storage_format);
repo->repository_format_worktree_config = format.worktree_config;
/* take ownership of format.partial_clone */
repo->repository_format_partial_clone = format.partial_clone;
format.partial_clone = NULL;
if (worktree)
repo_set_worktree(repo, worktree);
if (repo->compat_hash_algo)
repo_read_loose_object_map(repo);
clear_repository_format(&format);
return 0;
error:
repo_clear(repo);
return -1;
}
int repo_submodule_init(struct repository *subrepo,
struct repository *superproject,
const char *path,
const struct object_id *treeish_name)
{
struct strbuf gitdir = STRBUF_INIT;
struct strbuf worktree = STRBUF_INIT;
int ret = 0;
strbuf_repo_worktree_path(&gitdir, superproject, "%s/.git", path);
strbuf_repo_worktree_path(&worktree, superproject, "%s", path);
if (repo_init(subrepo, gitdir.buf, worktree.buf)) {
/*
* If initialization fails then it may be due to the submodule
* not being populated in the superproject's worktree. Instead
* we can try to initialize the submodule by finding it's gitdir
* in the superproject's 'modules' directory. In this case the
* submodule would not have a worktree.
*/
const struct submodule *sub =
submodule_from_path(superproject, treeish_name, path);
if (!sub) {
ret = -1;
goto out;
}
strbuf_reset(&gitdir);
submodule_name_to_gitdir(&gitdir, superproject, sub->name);
if (repo_init(subrepo, gitdir.buf, NULL)) {
ret = -1;
goto out;
}
}
subrepo->submodule_prefix = xstrfmt("%s%s/",
superproject->submodule_prefix ?
superproject->submodule_prefix :
"", path);
out:
strbuf_release(&gitdir);
strbuf_release(&worktree);
return ret;
}
static void repo_clear_path_cache(struct repo_path_cache *cache)
{
FREE_AND_NULL(cache->squash_msg);
FREE_AND_NULL(cache->squash_msg);
FREE_AND_NULL(cache->merge_msg);
FREE_AND_NULL(cache->merge_rr);
FREE_AND_NULL(cache->merge_mode);
FREE_AND_NULL(cache->merge_head);
FREE_AND_NULL(cache->fetch_head);
FREE_AND_NULL(cache->shallow);
}
void repo_clear(struct repository *repo)
{
struct hashmap_iter iter;
struct strmap_entry *e;
FREE_AND_NULL(repo->gitdir);
FREE_AND_NULL(repo->commondir);
FREE_AND_NULL(repo->graft_file);
FREE_AND_NULL(repo->index_file);
FREE_AND_NULL(repo->worktree);
FREE_AND_NULL(repo->submodule_prefix);
raw_object_store_clear(repo->objects);
FREE_AND_NULL(repo->objects);
parsed_object_pool_clear(repo->parsed_objects);
FREE_AND_NULL(repo->parsed_objects);
FREE_AND_NULL(repo->settings.fsmonitor);
if (repo->config) {
git_configset_clear(repo->config);
FREE_AND_NULL(repo->config);
}
if (repo->submodule_cache) {
submodule_cache_free(repo->submodule_cache);
repo->submodule_cache = NULL;
}
if (repo->index) {
discard_index(repo->index);
FREE_AND_NULL(repo->index);
}
if (repo->promisor_remote_config) {
promisor_remote_clear(repo->promisor_remote_config);
FREE_AND_NULL(repo->promisor_remote_config);
}
if (repo->remote_state) {
remote_state_clear(repo->remote_state);
FREE_AND_NULL(repo->remote_state);
}
strmap_for_each_entry(&repo->submodule_ref_stores, &iter, e)
ref_store_release(e->value);
strmap_clear(&repo->submodule_ref_stores, 1);
strmap_for_each_entry(&repo->worktree_ref_stores, &iter, e)
ref_store_release(e->value);
strmap_clear(&repo->worktree_ref_stores, 1);
repo_clear_path_cache(&repo->cached_paths);
}
int repo_read_index(struct repository *repo)
{
int res;
/* Complete the double-reference */
if (!repo->index) {
ALLOC_ARRAY(repo->index, 1);
index_state_init(repo->index, repo);
} else if (repo->index->repo != repo) {
BUG("repo's index should point back at itself");
}
res = read_index_from(repo->index, repo->index_file, repo->gitdir);
prepare_repo_settings(repo);
if (repo->settings.command_requires_full_index)
ensure_full_index(repo->index);
/*
* If sparse checkouts are in use, check whether paths with the
* SKIP_WORKTREE attribute are missing from the worktree; if not,
* clear that attribute for that path.
*/
clear_skip_worktree_from_present_files(repo->index);
return res;
}
int repo_hold_locked_index(struct repository *repo,
struct lock_file *lf,
int flags)
{
if (!repo->index_file)
BUG("the repo hasn't been setup");
return hold_lock_file_for_update(lf, repo->index_file, flags);
}