[Re-send PATCH v7 00/12] Deprecate .git/info/grafts

[Resent the cover letter, as I did not see it on public-inbox...]

It is fragile, as there is no way for the revision machinery to say "but now I want to traverse the graph ignoring the graft file" e.g. when pushing commits to a remote repository (which, as a consequence, can miss commits).

And we already have a better solution with `git replace --graft <comit> [<parent>...]`.

Changes since v6:

- Made --convert-graft-file issue a mere warning (instead of an error) when
  a graft leaves the parents unchanged, and is hence unnecessary.

- Modified the regression test for --convert-graft-file to succeed even when
  the GPG prerequisite is unmet (thanks, Gábor!).

- Reassured by Stefan's feedback, I refrained from reinstating the contrib/
  script.

Johannes Schindelin (12):
  argv_array: offer to split a string by whitespace
  commit: Let the callback of for_each_mergetag return on error
  replace: avoid using die() to indicate a bug
  replace: "libify" create_graft() and callees
  replace: prepare create_graft() for converting graft files wholesale
  replace: introduce --convert-graft-file
  Add a test for `git replace --convert-graft-file`
  Deprecate support for .git/info/grafts
  filter-branch: stop suggesting to use grafts
  technical/shallow: stop referring to grafts
  technical/shallow: describe why shallow cannot use replace refs
  Remove obsolete script to convert grafts to replace refs

 Documentation/git-filter-branch.txt       |   2 +-
 Documentation/git-replace.txt             |  11 +-
 Documentation/technical/shallow.txt       |  20 +-
 advice.c                                  |   2 +
 advice.h                                  |   1 +
 argv-array.c                              |  20 ++
 argv-array.h                              |   2 +
 builtin/replace.c                         | 234 ++++++++++++++++------
 commit.c                                  |  18 +-
 commit.h                                  |   4 +-
 contrib/convert-grafts-to-replace-refs.sh |  28 ---
 log-tree.c                                |  13 +-
 t/t6001-rev-list-graft.sh                 |   9 +
 t/t6050-replace.sh                        |  28 +++
 14 files changed, 274 insertions(+), 118 deletions(-)
 delete mode 100755 contrib/convert-grafts-to-replace-refs.sh

base-commit: 1f1cddd558b54bb0ce19c8ace353fd07b758510d
Published-As: https://github.com/dscho/git/releases/tag/deprecate-grafts-v7
Fetch-It-Via: git fetch https://github.com/dscho/git deprecate-grafts-v7

Interdiff vs v6:
 diff --git a/builtin/replace.c b/builtin/replace.c
 index 35394ec1874..a87fca045be 100644
 --- a/builtin/replace.c
 +++ b/builtin/replace.c
 @@ -429,7 +429,7 @@ static int check_mergetags(struct commit *commit, int argc, const char **argv)
  	return for_each_mergetag(check_one_mergetag, commit, &mergetag_data);
  }
  
 -static int create_graft(int argc, const char **argv, int force)
 +static int create_graft(int argc, const char **argv, int force, int gentle)
  {
  	struct object_id old_oid, new_oid;
  	const char *old_ref = argv[0];
 @@ -471,8 +471,13 @@ static int create_graft(int argc, const char **argv, int force)
  
  	strbuf_release(&buf);
  
 -	if (!oidcmp(&old_oid, &new_oid))
 +	if (!oidcmp(&old_oid, &new_oid)) {
 +		if (gentle) {
 +			warning("graft for '%s' unnecessary", oid_to_hex(&old_oid));
 +			return 0;
 +		}
  		return error("new commit is the same as the old one: '%s'", oid_to_hex(&old_oid));
 +	}
  
  	return replace_object_oid(old_ref, &old_oid, "replacement", &new_oid, force);
  }
 @@ -492,7 +497,7 @@ static int convert_graft_file(int force)
  			continue;
  
  		argv_array_split(&args, buf.buf);
 -		if (args.argc && create_graft(args.argc, args.argv, force))
 +		if (args.argc && create_graft(args.argc, args.argv, force, 1))
  			strbuf_addf(&err, "\n\t%s", buf.buf);
  		argv_array_clear(&args);
  	}
 @@ -583,7 +588,7 @@ int cmd_replace(int argc, const char **argv, const char *prefix)
  		if (argc < 1)
  			usage_msg_opt("-g needs at least one argument",
  				      git_replace_usage, options);
 -		return create_graft(argc, argv, force);
 +		return create_graft(argc, argv, force, 0);
  
  	case MODE_CONVERT_GRAFT_FILE:
  		if (argc != 0)
 diff --git a/t/t6050-replace.sh b/t/t6050-replace.sh
 index bed86a0af3d..d174bfed309 100755
 --- a/t/t6050-replace.sh
 +++ b/t/t6050-replace.sh
 @@ -445,6 +445,14 @@ test_expect_success GPG '--graft on a commit with a mergetag' '
  '
  
  test_expect_success '--convert-graft-file' '
 +	git checkout -b with-graft-file &&
 +	test_commit root2 &&
 +	git reset --hard root2^ &&
 +	test_commit root1 &&
 +	test_commit after-root1 &&
 +	test_tick &&
 +	git merge -m merge-root2 root2 &&
 +
  	: add and convert graft file &&
  	printf "%s\n%s %s\n\n# comment\n%s\n" \
  		$(git rev-parse HEAD^^ HEAD^ HEAD^^ HEAD^2) \