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[PATCH 7/8] repository: adjust repo paths when $CWD moves

From
Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Date
Mar 28, 2018, 17:55 UTC
Message-ID
<20180328175537.17450-8-pclouds@gmail.com>
In-Reply-To
<20180328175537.17450-1-pclouds@gmail.com>
From: Duy Nguyen <pclouds@gmail.com>

As noted in previous and previous patches, when setup_work_tree() moves $CWD, it calls set_git_dir() with a new path to make sure relative $GIT_DIR is still correct.

The same problem from the previous patch applies here: if $GIT_ALTERNATE_OBJECT_DIRECTORIES or $GIT_OBJECT_DIRECTORY are also relative, the user is screwed.

Fortuntely the previous patch indirectly fixes this as well: update_path_envs() in environment.c is actually called before setup_git_env() is indirectly called by setup_work_tree() via set_git_dir(). At that point, it correctly gets the updated paths from env and pass them down. This patch is here for another reason.

From the design perspective, calling set_git_dir() the second time [1] is just bad because it could potentially be used to point repo code to _another_ repository. The promise that "the new path actually points to the same place as the old one" is not guaranteed and also hard to see unless you know setup code well.

This patch avoids this. The second set_git_dir() call is just a workaround to adjust paths. We can now do it directly from repo code by subscribing to the "$CWD updated" event and do everything needed by the repo. After this we could die() on subsequent repo_set_gitdir() calls because we do not support it (we never did).

[1] The first time is done by setup_git_directory() code, which is correct: we have just found a repo and we want to initialize our code to read from that repo.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
---
 object-store.h |  3 +++
 object.c       | 15 +++++++++++++++
 repository.c   | 28 ++++++++++++++++++++++++++++
 setup.c        |  6 +-----
 4 files changed, 47 insertions(+), 5 deletions(-)
diff --git a/object-store.h b/object-store.h
index fef33f345f..4af2c53bca 100644
--- a/object-store.h
+++ b/object-store.h
@@ -119,6 +119,9 @@ struct raw_object_store {
 };
 
 struct raw_object_store *raw_object_store_new(void);
+void raw_object_store_adjust_paths(struct raw_object_store *o,
+				   const char *old_cwd,
+				   const char *new_cwd);
 void raw_object_store_clear(struct raw_object_store *o);
 
 /*
diff --git a/object.c b/object.c
index a0a756f24f..5318922efd 100644
--- a/object.c
+++ b/object.c
@@ -457,6 +457,21 @@ struct raw_object_store *raw_object_store_new(void)
 	return o;
 }
 
+void raw_object_store_adjust_paths(struct raw_object_store *o,
+				   const char *old_cwd,
+				   const char *new_cwd)
+{
+	/*
+	 * "main repo" is technically wrong because we don't know that
+	 * from here. But it's the only repo that will execute this
+	 * function for now.
+	 */
+	setup_adjust_path("main repo's object dir",
+			  &o->objectdir, old_cwd, new_cwd);
+	setup_adjust_path("main repo's alt dir",
+			  &o->alternate_db, old_cwd, new_cwd);
+}
+
 static void free_alt_odb(struct alternate_object_database *alt)
 {
 	strbuf_release(&alt->scratch);
diff --git a/repository.c b/repository.c
index a4848c1bd0..c2edf227fe 100644
--- a/repository.c
+++ b/repository.c
@@ -8,6 +8,10 @@
 static struct repository the_repo;
 struct repository *the_repository;
 
+static void repo_adjust_paths(const char *old_cwd,
+			      const char *new_cwd,
+			      void *cb_data);
+
 void initialize_the_repository(void)
 {
 	the_repository = &the_repo;
@@ -15,6 +19,11 @@ void initialize_the_repository(void)
 	the_repo.index = &the_index;
 	the_repo.objects = raw_object_store_new();
 	repo_set_hash_algo(&the_repo, GIT_HASH_SHA1);
+	/*
+	 * non-main repos probably does not need this since $CWD should
+	 * never change again by the time they are created.
+	 */
+	add_cwd_update_callback(repo_adjust_paths, the_repository);
 }
 
 static void expand_base_dir(char **out, const char *in,
@@ -70,6 +79,25 @@ void repo_set_gitdir(struct repository *repo,
 			repo->gitdir, "index");
 }
 
+static void repo_adjust_paths(const char *old_cwd, const char *new_cwd,
+			      void *cb_data)
+{
+	struct repository *repo = cb_data;
+
+	if (repo != the_repository)
+		die("BUG: this is supposed to happen to main repo only");
+
+	setup_adjust_path("main repo's gitdir",
+			  &repo->gitdir, old_cwd, new_cwd);
+	setup_adjust_path("main repo's commondir",
+			  &repo->commondir, old_cwd, new_cwd);
+	setup_adjust_path("main repo's graft file",
+			  &repo->graft_file, old_cwd, new_cwd);
+	setup_adjust_path("main repo's index file",
+			  &repo->index_file, old_cwd, new_cwd);
+	raw_object_store_adjust_paths(repo->objects, old_cwd, new_cwd);
+}
+
 void repo_set_hash_algo(struct repository *repo, int hash_algo)
 {
 	repo->hash_algo = &hash_algos[hash_algo];
diff --git a/setup.c b/setup.c
index 23b8f89ce2..e364aea7e5 100644
--- a/setup.c
+++ b/setup.c
@@ -417,7 +417,7 @@ void setup_adjust_path(const char *name, char **path,
 void setup_work_tree(void)
 {
 	static int initialized = 0;
-	const char *work_tree, *git_dir;
+	const char *work_tree;
 	struct strbuf old_cwd = STRBUF_INIT;
 	int i;
 
@@ -428,9 +428,6 @@ void setup_work_tree(void)
 		die(_("unable to set up work tree using invalid config"));
 
 	work_tree = get_git_work_tree();
-	git_dir = get_git_dir();
-	if (!is_absolute_path(git_dir))
-		git_dir = real_path(get_git_dir());
 	strbuf_get_pwd_cwd(&old_cwd);
 	if (!work_tree || chdir(work_tree))
 		die(_("this operation must be run in a work tree"));
@@ -439,7 +436,6 @@ void setup_work_tree(void)
 		cwd_callbacks[i].fn(old_cwd.buf, work_tree,
 				    cwd_callbacks[i].cb_data);
 	strbuf_release(&old_cwd);
-	set_git_dir(remove_leading_path(git_dir, work_tree));
 	initialized = 1;
 }
 

-- 
2.17.0.rc1.439.gca064e2955
Previous: Nguyễn Thái Ngọc DuyNext: Jeff King
Message 50 of 54 in “git complains packed-refs is not a directory when used with GIT_DIR and GIT_WORK_TREE envvars.”
  1. Rafael AscensaoMar 26, 2018
  2. Ævar Arnfjörð BjarmasonMar 26, 2018
  3. Jeff KingMar 27, 2018
  4. Duy NguyenMar 27, 2018
  5. Jeff KingMar 27, 2018
  6. Duy NguyenMar 27, 2018
  7. Duy NguyenMar 27, 2018
  8. Jeff KingMar 28, 2018
  9. Duy NguyenMar 28, 2018
  10. Jeff KingMar 28, 2018
  11. 1/4 set_git_dir: die when setenv() failsJeff King, Mar 28, 2018
  12. 2/4 add chdir-notify APIJeff King, Mar 28, 2018
  13. Eric SunshineMar 28, 2018
  14. Jeff KingMar 28, 2018
  15. Duy NguyenMar 29, 2018
  16. Jeff KingMar 29, 2018
  17. Duy NguyenMar 29, 2018
  18. 3/4 set_work_tree: use chdir_notifyJeff King, Mar 28, 2018
  19. Duy NguyenMar 29, 2018
  20. Duy NguyenMar 29, 2018
  21. Jeff KingMar 29, 2018
  22. Jeff KingMar 29, 2018
  23. Duy NguyenMar 29, 2018
  24. Jeff KingMar 30, 2018
  25. 4/4 refs: use chdir_notify to update cached relative pathsJeff King, Mar 28, 2018
  26. 0/5 re-parenting relative directories after chdirJeff King, Mar 30, 2018
  27. 1/5 set_git_dir: die when setenv() failsJeff King, Mar 30, 2018
  28. 2/5 trace.c: export trace_setup_keyJeff King, Mar 30, 2018
  29. Junio C HamanoMar 30, 2018
  30. Jeff KingMar 30, 2018
  31. Junio C HamanoMar 30, 2018
  32. Jeff KingMar 30, 2018
  33. 3/5 add chdir-notify APIJeff King, Mar 30, 2018
  34. 4/5 set_work_tree: use chdir_notifyJeff King, Mar 30, 2018
  35. 5/5 refs: use chdir_notify to update cached relative pathsJeff King, Mar 30, 2018
  36. Duy NguyenMar 30, 2018
  37. Jeff KingMar 28, 2018
  38. 0/8 Re: git complains packed-refs is not a directory when used with GIT_DIR and GIT_WORK_TREE envvars.Nguyễn Thái Ngọc Duy, Mar 28, 2018
  39. 1/8 strbuf.c: add strbuf_ensure_trailing_dr_sep()Nguyễn Thái Ngọc Duy, Mar 28, 2018
  40. 2/8 strbuf.c: reintroduce get_pwd_cwd() (with strbuf_ prefix)Nguyễn Thái Ngọc Duy, Mar 28, 2018
  41. Stefan BellerMar 28, 2018
  42. Duy NguyenMar 28, 2018
  43. 3/8 trace.c: export trace_setup_keyNguyễn Thái Ngọc Duy, Mar 28, 2018
  44. 4/8 setup.c: introduce setup_adjust_path()Nguyễn Thái Ngọc Duy, Mar 28, 2018
  45. 5/8 setup.c: allow other code to be notified when $CWD movesNguyễn Thái Ngọc Duy, Mar 28, 2018
  46. 6/8 environment.c: adjust env containing relpath when $CWD is movedNguyễn Thái Ngọc Duy, Mar 28, 2018
  47. Jeff KingMar 28, 2018
  48. Duy NguyenMar 28, 2018
  49. 8/8 refs: adjust main repo paths when $CWD movesNguyễn Thái Ngọc Duy, Mar 28, 2018
  50. 7/8 repository: adjust repo paths when $CWD movesNguyễn Thái Ngọc Duy, Mar 28, 2018
  51. Jeff KingMar 28, 2018
  52. Duy NguyenMar 29, 2018
  53. Jeff KingMar 30, 2018
  54. Junio C HamanoMar 28, 2018

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