[PATCH v3 0/5] First steps towards partial clone submodules

I think I've addressed all review comments. As for Junio's suggestion about also printing the type in the former patch 4 (now patch 5) [1], I decided to just leave the code as-is and not also print the type.

The main changes are that patch 1 is somewhat rewritten - we still remove the global variable, but we no longer read the extensions.partialClone config directly from promisor-remote.c. Instead, we store it in struct repository when the format of a repository is being verified, and promisor-remote.c merely reads it from there. Patch 3 is a new patch that updates the environment variable preparation before it is moved in patch 4 (formerly patch 3).

[1] https://lore.kernel.org/git/xmqq7dj2ik7k.fsf@gitster.g/

Jonathan Tan (5):
  repository: move global r_f_p_c to repo struct
  promisor-remote: support per-repository config
  submodule: refrain from filtering GIT_CONFIG_COUNT
  run-command: refactor subprocess env preparation
  promisor-remote: teach lazy-fetch in any repo

 Makefile                      |   1 +
 object-file.c                 |   7 +--
 promisor-remote.c             | 108 ++++++++++++++++++----------------
 promisor-remote.h             |  28 ++++++---
 repository.c                  |   9 +++
 repository.h                  |   5 ++
 run-command.c                 |  12 ++++
 run-command.h                 |  10 ++++
 setup.c                       |  16 +++--
 submodule.c                   |  17 +-----
 t/helper/test-partial-clone.c |  43 ++++++++++++++
 t/helper/test-tool.c          |   1 +
 t/helper/test-tool.h          |   1 +
 t/t0410-partial-clone.sh      |  23 ++++++++
 14 files changed, 196 insertions(+), 85 deletions(-)
 create mode 100644 t/helper/test-partial-clone.c

Range-diff against v2:
1:  d99598ca50 < -:  ---------- promisor-remote: read partialClone config here
-:  ---------- > 1:  255d112256 repository: move global r_f_p_c to repo struct
2:  5a1ccae335 ! 2:  a52448cff2 promisor-remote: support per-repository config
    @@ promisor-remote.c
      #include "transport.h"
      #include "strvec.h"
      
    --static char *repository_format_partial_clone;
     +struct promisor_remote_config {
    -+	char *repository_format_partial_clone;
     +	struct promisor_remote *promisors;
     +	struct promisor_remote **promisors_tail;
     +};
    - 
    ++
      static int fetch_objects(const char *remote_name,
      			 const struct object_id *oids,
    + 			 int oid_nr)
     @@ promisor-remote.c: static int fetch_objects(const char *remote_name,
      	return finish_command(&child) ? -1 : 0;
      }
    @@ promisor-remote.c: static void promisor_remote_move_to_tail(struct promisor_remo
      	const char *name;
      	size_t namelen;
      	const char *subkey;
    -@@ promisor-remote.c: static int promisor_remote_config(const char *var, const char *value, void *data
    - 		 * NULL value is handled in handle_extension_v0 in setup.c.
    - 		 */
    - 		if (value)
    --			repository_format_partial_clone = xstrdup(value);
    -+			config->repository_format_partial_clone = xstrdup(value);
    - 		return 0;
    - 	}
    - 
     @@ promisor-remote.c: static int promisor_remote_config(const char *var, const char *value, void *data
      
      		remote_name = xmemdupz(name, namelen);
    @@ promisor-remote.c: static int promisor_remote_config(const char *var, const char
     +	config->promisors_tail = &config->promisors;
      
     -	git_config(promisor_remote_config, NULL);
    -+	git_config(promisor_remote_config, config);
    ++	repo_config(r, promisor_remote_config, config);
      
    --	if (repository_format_partial_clone) {
    -+	if (config->repository_format_partial_clone) {
    +-	if (the_repository->repository_format_partial_clone) {
    ++	if (r->repository_format_partial_clone) {
      		struct promisor_remote *o, *previous;
      
    --		o = promisor_remote_lookup(repository_format_partial_clone,
    +-		o = promisor_remote_lookup(the_repository->repository_format_partial_clone,
     +		o = promisor_remote_lookup(config,
    -+					   config->repository_format_partial_clone,
    ++					   r->repository_format_partial_clone,
      					   &previous);
      		if (o)
     -			promisor_remote_move_to_tail(o, previous);
     +			promisor_remote_move_to_tail(config, o, previous);
      		else
    --			promisor_remote_new(repository_format_partial_clone);
    -+			promisor_remote_new(config, config->repository_format_partial_clone);
    +-			promisor_remote_new(the_repository->repository_format_partial_clone);
    ++			promisor_remote_new(config, r->repository_format_partial_clone);
      	}
      }
      
    @@ promisor-remote.c: static int promisor_remote_config(const char *var, const char
     -	while (promisors) {
     -		struct promisor_remote *r = promisors;
     -		promisors = promisors->next;
    -+	FREE_AND_NULL(config->repository_format_partial_clone);
    -+
     +	while (config->promisors) {
     +		struct promisor_remote *r = config->promisors;
     +		config->promisors = config->promisors->next;
    @@ repository.h: struct lock_file;
      enum untracked_cache_setting {
      	UNTRACKED_CACHE_UNSET = -1,
     @@ repository.h: struct repository {
    - 	/* True if commit-graph has been disabled within this process. */
    - 	int commit_graph_disabled;
      
    -+	/* Configurations related to promisor remotes. */
    + 	/* Configurations related to promisor remotes. */
    + 	char *repository_format_partial_clone;
     +	struct promisor_remote_config *promisor_remote_config;
    -+
    + 
      	/* Configurations */
      
    - 	/* Indicate if a repository has a different 'commondir' from 'gitdir' */
-:  ---------- > 3:  e1a40108f4 submodule: refrain from filtering GIT_CONFIG_COUNT
3:  3f7c4e6e67 ! 4:  fd6907822c run-command: move envvar-resetting function
    @@ Metadata
     Author: Jonathan Tan <jonathantanmy@google.com>
     
      ## Commit message ##
    -    run-command: move envvar-resetting function
    +    run-command: refactor subprocess env preparation
     
    -    There is a function that resets environment variables, used when
    -    invoking a sub-process in a submodule. The lazy-fetching code (used in
    -    partial clones) will need this function in a subsequent commit, so move
    -    it to a more central location.
    +    submodule.c has functionality that prepares the environment for running
    +    a subprocess in a new repo. The lazy-fetching code (used in partial
    +    clones) will need this in a subsequent commit, so move it to a more
    +    central location.
     
         Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
     
    @@ run-command.c: int run_auto_maintenance(int quiet)
      	return run_command(&maint);
      }
     +
    -+void prepare_other_repo_env(struct strvec *env_array)
    ++void prepare_other_repo_env(struct strvec *env_array, const char *new_git_dir)
     +{
     +	const char * const *var;
     +
     +	for (var = local_repo_env; *var; var++) {
    -+		if (strcmp(*var, CONFIG_DATA_ENVIRONMENT))
    ++		if (strcmp(*var, CONFIG_DATA_ENVIRONMENT) &&
    ++		    strcmp(*var, CONFIG_COUNT_ENVIRONMENT))
     +			strvec_push(env_array, *var);
     +	}
    ++	strvec_pushf(env_array, "%s=%s", GIT_DIR_ENVIRONMENT, new_git_dir);
     +}
     
      ## run-command.h ##
    @@ run-command.h: int run_processes_parallel_tr2(int n, get_next_task_fn, start_fai
      			       const char *tr2_category, const char *tr2_label);
      
     +/**
    -+ * Convenience function which adds all GIT_* environment variables to env_array
    -+ * with the exception of GIT_CONFIG_PARAMETERS. When used as the env_array of a
    -+ * subprocess, these entries cause the corresponding environment variables to
    -+ * be unset in the subprocess. See local_repo_env in cache.h for more
    ++ * Convenience function which prepares env_array for a command to be run in a
    ++ * new repo. This adds all GIT_* environment variables to env_array with the
    ++ * exception of GIT_CONFIG_PARAMETERS (which cause the corresponding
    ++ * environment variables to be unset in the subprocess) and adds an environment
    ++ * variable pointing to new_git_dir. See local_repo_env in cache.h for more
     + * information.
     + */
    -+void prepare_other_repo_env(struct strvec *env_array);
    ++void prepare_other_repo_env(struct strvec *env_array, const char *new_git_dir);
     +
      #endif
     
    @@ submodule.c: static void print_submodule_diff_summary(struct repository *r, stru
     -	const char * const *var;
     -
     -	for (var = local_repo_env; *var; var++) {
    --		if (strcmp(*var, CONFIG_DATA_ENVIRONMENT))
    +-		if (strcmp(*var, CONFIG_DATA_ENVIRONMENT) &&
    +-		    strcmp(*var, CONFIG_COUNT_ENVIRONMENT))
     -			strvec_push(out, *var);
     -	}
     -}
    @@ submodule.c: static void print_submodule_diff_summary(struct repository *r, stru
      void prepare_submodule_repo_env(struct strvec *out)
      {
     -	prepare_submodule_repo_env_no_git_dir(out);
    -+	prepare_other_repo_env(out);
    - 	strvec_pushf(out, "%s=%s", GIT_DIR_ENVIRONMENT,
    - 		     DEFAULT_GIT_DIR_ENVIRONMENT);
    +-	strvec_pushf(out, "%s=%s", GIT_DIR_ENVIRONMENT,
    +-		     DEFAULT_GIT_DIR_ENVIRONMENT);
    ++	prepare_other_repo_env(out, DEFAULT_GIT_DIR_ENVIRONMENT);
      }
      
      static void prepare_submodule_repo_env_in_gitdir(struct strvec *out)
      {
     -	prepare_submodule_repo_env_no_git_dir(out);
    -+	prepare_other_repo_env(out);
    - 	strvec_pushf(out, "%s=.", GIT_DIR_ENVIRONMENT);
    +-	strvec_pushf(out, "%s=.", GIT_DIR_ENVIRONMENT);
    ++	prepare_other_repo_env(out, ".");
      }
      
    + /*
4:  655607d575 ! 5:  a6d73662b1 promisor-remote: teach lazy-fetch in any repo
    @@ Commit message
         prevents testing of the functionality in this patch by user-facing
         commands. So for now, test this mechanism using a test helper.
     
    +    Besides that, there is some code that uses the wrapper functions
    +    like has_promisor_remote(). Those will need to be checked to see if they
    +    could support the non-wrapper functions instead (and thus support any
    +    repository, not just the_repository).
    +
         Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
     
      ## Makefile ##
    @@ promisor-remote.c: static int fetch_objects(const char *remote_name,
      
      	child.git_cmd = 1;
      	child.in = -1;
    -+	if (repo != the_repository) {
    -+		prepare_other_repo_env(&child.env_array);
    -+		strvec_pushf(&child.env_array, "%s=%s", GIT_DIR_ENVIRONMENT,
    -+			     repo->gitdir);
    -+	}
    ++	if (repo != the_repository)
    ++		prepare_other_repo_env(&child.env_array, repo->gitdir);
      	strvec_pushl(&child.args, "-c", "fetch.negotiationAlgorithm=noop",
      		     "fetch", remote_name, "--no-tags",
      		     "--no-write-fetch-head", "--recurse-submodules=no",
    -@@ promisor-remote.c: static void promisor_remote_init(struct repository *r)
    - 		xcalloc(sizeof(*r->promisor_remote_config), 1);
    - 	config->promisors_tail = &config->promisors;
    - 
    --	git_config(promisor_remote_config, config);
    -+	repo_config(r, promisor_remote_config, config);
    - 
    - 	if (config->repository_format_partial_clone) {
    - 		struct promisor_remote *o, *previous;
     @@ promisor-remote.c: int promisor_remote_get_direct(struct repository *repo,
      
      	promisor_remote_init(repo);