[PATCH v5 00/27] Prepare the sequencer for the upcoming rebase -i patches

This patch series marks the '4' in the countdown to speed up rebase -i by implementing large parts in C (read: there will be three more patch series after that before the full benefit hits git.git: sequencer-i, rebase--helper and rebase-i-extra). It is based on the `libify-sequencer` patch series I submitted earlier.

The patches in this series merely prepare the sequencer code for the next patch series that actually teaches the sequencer to run rebase -i's commands.

The reason to split these two patch series is simple: to keep them at a sensible size.

The two patch series after that are much smaller: a two-patch "series" that switches rebase -i to use the sequencer (except with --root or --preserve-merges), and a couple of patches to move several pretty expensive script processing steps to C (think: autosquash).

The end game of this patch series is a git-rebase--helper that makes rebase -i 5x faster on Windows (according to t/perf/p3404). Travis says that even MacOSX and Linux benefit (4x and 3x, respectively).

I have been working on this since early February, whenever time allowed, and it is time to put it into the users' hands. To that end, I already integrated the whole shebang into Git for Windows 2.10.0 and 2.10.1 where it has been running without complaints (and some quite positive feedback).

It would be *really* nice if we could get this patch series at least into `next` soon, as it gets late and later for the rest of the patches to make it into `master` in time for v2.11 (and it is not for lack of trying on my end...).

Changes vs v4:

- clarified in a code comment that read_oneliner() is lenient when it
  comes to multi-line files: it still reads the entire file, but strips
  off only the final EOL (if any).

- rephrased a commit message to stop judging Junio's taste ;-)

- changed "strip LF" to "skip LF", as requested.

- rephrased a commit message to talk about pluggin memory leaks instead
  of stating that the memory is now eventually released.

- dropped the "sequencer: do not try to commit when there were merge
  conflicts" patch that appears to be no longer necessary.

- split and modified the commit refactoring write_message() according to
  Junio's suggestions.

Johannes Schindelin (27):
  sequencer: use static initializers for replay_opts
  sequencer: use memoized sequencer directory path
  sequencer: avoid unnecessary indirection
  sequencer: future-proof remove_sequencer_state()
  sequencer: plug memory leaks for the option values
  sequencer: future-proof read_populate_todo()
  sequencer: refactor the code to obtain a short commit name
  sequencer: completely revamp the "todo" script parsing
  sequencer: strip CR from the todo script
  sequencer: avoid completely different messages for different actions
  sequencer: get rid of the subcommand field
  sequencer: remember the onelines when parsing the todo file
  sequencer: prepare for rebase -i's commit functionality
  sequencer: introduce a helper to read files written by scripts
  sequencer: allow editing the commit message on a case-by-case basis
  sequencer: support amending commits
  sequencer: support cleaning up commit messages
  sequencer: left-trim lines read from the script
  sequencer: stop releasing the strbuf in write_message()
  sequencer: roll back lock file if write_message() failed
  sequencer: refactor write_message() to take a pointer/length
  sequencer: teach write_message() to append an optional LF
  sequencer: remove overzealous assumption in rebase -i mode
  sequencer: mark action_name() for translation
  sequencer: quote filenames in error messages
  sequencer: start error messages consistently with lower case
  sequencer: mark all error messages for translation

 builtin/commit.c              |   2 +-
 builtin/revert.c              |  46 ++-
 sequencer.c                   | 680 ++++++++++++++++++++++++++++--------------
 sequencer.h                   |  23 +-
 t/t3501-revert-cherry-pick.sh |   2 +-
 5 files changed, 492 insertions(+), 261 deletions(-)

base-commit: 659889482ac63411daea38b2c3d127842ea04e4d
Published-As: https://github.com/dscho/git/releases/tag/prepare-sequencer-v5
Fetch-It-Via: git fetch https://github.com/dscho/git prepare-sequencer-v5

Interdiff vs v4:

 diff --git a/sequencer.c b/sequencer.c
 index 1cf70f7..a61fe76 100644
 --- a/sequencer.c
 +++ b/sequencer.c
 @@ -234,8 +234,8 @@ static void print_advice(int show_hint, struct replay_opts *opts)
  	}
  }
  
 -static int write_with_lock_file(const char *filename,
 -				const void *buf, size_t len, int append_eol)
 +static int write_message(const void *buf, size_t len, const char *filename,
 +			 int append_eol)
  {
  	static struct lock_file msg_file;
  
 @@ -258,16 +258,12 @@ static int write_with_lock_file(const char *filename,
  	return 0;
  }
  
 -static int write_message(struct strbuf *msgbuf, const char *filename)
 -{
 -	int res = write_with_lock_file(filename, msgbuf->buf, msgbuf->len, 0);
 -	strbuf_release(msgbuf);
 -	return res;
 -}
 -
  /*
 - * Reads a file that was presumably written by a shell script, i.e.
 - * with an end-of-line marker that needs to be stripped.
 + * Reads a file that was presumably written by a shell script, i.e. with an
 + * end-of-line marker that needs to be stripped.
 + *
 + * Note that only the last end-of-line marker is stripped, consistent with the
 + * behavior of "$(cat path)" in a shell script.
   *
   * Returns 1 if the file was read, 0 if it could not be read or does not exist.
   */
 @@ -762,12 +758,14 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
  					 head, &msgbuf, opts);
  		if (res < 0)
  			return res;
 -		res |= write_message(&msgbuf, git_path_merge_msg());
 +		res |= write_message(msgbuf.buf, msgbuf.len,
 +				     git_path_merge_msg(), 0);
  	} else {
  		struct commit_list *common = NULL;
  		struct commit_list *remotes = NULL;
  
 -		res = write_message(&msgbuf, git_path_merge_msg());
 +		res = write_message(msgbuf.buf, msgbuf.len,
 +				    git_path_merge_msg(), 0);
  
  		commit_list_insert(base, &common);
  		commit_list_insert(next, &remotes);
 @@ -777,6 +775,7 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
  		free_commit_list(common);
  		free_commit_list(remotes);
  	}
 +	strbuf_release(&msgbuf);
  
  	/*
  	 * If the merge was clean or if it failed due to conflict, we write
 @@ -808,7 +807,7 @@ static int do_pick_commit(enum todo_command command, struct commit *commit,
  		res = allow;
  		goto leave;
  	}
 -	if (!res && !opts->no_commit)
 +	if (!opts->no_commit)
  		res = run_git_commit(opts->edit ? NULL : git_path_merge_msg(),
  				     opts, allow, opts->edit, 0, 0);
  
 @@ -934,7 +933,7 @@ static int parse_insn_buffer(char *buf, struct todo_list *todo_list)
  	for (i = 1; *p; i++, p = next_p) {
  		char *eol = strchrnul(p, '\n');
  
 -		next_p = *eol ? eol + 1 /* strip LF */ : eol;
 +		next_p = *eol ? eol + 1 /* skip LF */ : eol;
  
  		if (p != eol && eol[-1] == '\r')
  			eol--; /* strip Carriage Return */