Merge branch 'nd/shallow-clone'

Fetching from a shallow-cloned repository used to be forbidden,
primarily because the codepaths involved were not carefully vetted
and we did not bother supporting such usage. This attempts to allow
object transfer out of a shallow-cloned repository in a controlled
way (i.e. the receiver become a shallow repository with truncated
history).

* nd/shallow-clone: (31 commits)
  t5537: fix incorrect expectation in test case 10
  shallow: remove unused code
  send-pack.c: mark a file-local function static
  git-clone.txt: remove shallow clone limitations
  prune: clean .git/shallow after pruning objects
  clone: use git protocol for cloning shallow repo locally
  send-pack: support pushing from a shallow clone via http
  receive-pack: support pushing to a shallow clone via http
  smart-http: support shallow fetch/clone
  remote-curl: pass ref SHA-1 to fetch-pack as well
  send-pack: support pushing to a shallow clone
  receive-pack: allow pushes that update .git/shallow
  connected.c: add new variant that runs with --shallow-file
  add GIT_SHALLOW_FILE to propagate --shallow-file to subprocesses
  receive/send-pack: support pushing from a shallow clone
  receive-pack: reorder some code in unpack()
  fetch: add --update-shallow to accept refs that update .git/shallow
  upload-pack: make sure deepening preserves shallow roots
  fetch: support fetching from a shallow repository
  clone: support remote shallow repository
  ...

1 files changed, 33 insertions, 4 deletions

diff --git a/commit.h b/commit.h
index f8a451d864..16d9c43513 100644
--- a/commit.h
+++ b/commit.h
@@ -194,6 +194,8 @@ extern struct commit_list *get_octopus_merge_bases(struct commit_list *in);
 /* largest positive number a signed 32-bit integer can contain */
 #define INFINITE_DEPTH 0x7fffffff
 
+struct sha1_array;
+struct ref;
 extern int register_shallow(const unsigned char *sha1);
 extern int unregister_shallow(const unsigned char *sha1);
 extern int for_each_commit_graft(each_commit_graft_fn, void *);
@@ -201,11 +203,38 @@ extern int is_repository_shallow(void);
 extern struct commit_list *get_shallow_commits(struct object_array *heads,
 		int depth, int shallow_flag, int not_shallow_flag);
 extern void check_shallow_file_for_update(void);
-extern void set_alternate_shallow_file(const char *path);
-extern int write_shallow_commits(struct strbuf *out, int use_pack_protocol);
+extern void set_alternate_shallow_file(const char *path, int override);
+extern int write_shallow_commits(struct strbuf *out, int use_pack_protocol,
+				 const struct sha1_array *extra);
 extern void setup_alternate_shallow(struct lock_file *shallow_lock,
-				    const char **alternate_shallow_file);
-extern char *setup_temporary_shallow(void);
+				    const char **alternate_shallow_file,
+				    const struct sha1_array *extra);
+extern char *setup_temporary_shallow(const struct sha1_array *extra);
+extern void advertise_shallow_grafts(int);
+
+struct shallow_info {
+	struct sha1_array *shallow;
+	int *ours, nr_ours;
+	int *theirs, nr_theirs;
+	struct sha1_array *ref;
+
+	/* for receive-pack */
+	uint32_t **used_shallow;
+	int *need_reachability_test;
+	int *reachable;
+	int *shallow_ref;
+	struct commit **commits;
+	int nr_commits;
+};
+
+extern void prepare_shallow_info(struct shallow_info *, struct sha1_array *);
+extern void clear_shallow_info(struct shallow_info *);
+extern void remove_nonexistent_theirs_shallow(struct shallow_info *);
+extern void assign_shallow_commits_to_refs(struct shallow_info *info,
+					   uint32_t **used,
+					   int *ref_status);
+extern int delayed_reachability_test(struct shallow_info *si, int c);
+extern void prune_shallow(int show_only);
 
 int is_descendant_of(struct commit *, struct commit_list *);
 int in_merge_bases(struct commit *, struct commit *);