commit: --fixup option for use with rebase --autosquash

This option makes it convenient to construct commit messages for use
with 'rebase --autosquash'.  The resulting commit message will be
"fixup! ..." where "..." is the subject line of the specified commit
message.

Example usage:
$ git commit --fixup HEAD~2

Signed-off-by: Pat Notz <patnotz@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-commit.txt b/Documentation/git-commit.txt
index 42fb1f57b21d7c355d3df6be07329c478786a9a7..f4a2b8c89776b704df598560209ab9ad7f9023cf 100644 (file)
--- a/Documentation/git-commit.txt
+++ b/Documentation/git-commit.txt
@@ -9,10 +9,10 @@ SYNOPSIS
 --------
 [verse]
 'git commit' [-a | --interactive] [-s] [-v] [-u<mode>] [--amend] [--dry-run]
-          [(-c | -C) <commit>] [-F <file> | -m <msg>] [--reset-author]
-          [--allow-empty] [--allow-empty-message] [--no-verify] [-e] [--author=<author>]
-          [--date=<date>] [--cleanup=<mode>] [--status | --no-status] [--]
-          [[-i | -o ]<file>...]
+          [(-c | -C | --fixup) <commit>] [-F <file> | -m <msg>]
+          [--reset-author] [--allow-empty] [--allow-empty-message] [--no-verify]
+          [-e] [--author=<author>] [--date=<date>] [--cleanup=<mode>]
+          [--status | --no-status] [--] [[-i | -o ]<file>...]
 
 DESCRIPTION
 -----------
@@ -70,6 +70,12 @@ OPTIONS
        Like '-C', but with '-c' the editor is invoked, so that
        the user can further edit the commit message.
 
+--fixup=<commit>::
+       Construct a commit message for use with `rebase --autosquash`.
+       The commit message will be the subject line from the specified
+       commit with a prefix of "fixup! ".  See linkgit:git-rebase[1]
+       for details.
+
 --reset-author::
        When used with -C/-c/--amend options, declare that the
        authorship of the resulting commit now belongs of the committer.

diff --git a/builtin/commit.c b/builtin/commit.c
index 54fcc6d142e4bb73f9dde1f0658af23d1b1b1272..22498c6811abe124018253688f054065edcc9444 100644 (file)
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -69,6 +69,7 @@ static enum {
 static const char *logfile, *force_author;
 static const char *template_file;
 static char *edit_message, *use_message;
+static char *fixup_message;
 static char *author_name, *author_email, *author_date;
 static int all, edit_flag, also, interactive, only, amend, signoff;
 static int quiet, verbose, no_verify, allow_empty, dry_run, renew_authorship;
@@ -124,6 +125,7 @@ static struct option builtin_commit_options[] = {
        OPT_CALLBACK('m', "message", &message, "MESSAGE", "specify commit message", opt_parse_m),
        OPT_STRING('c', "reedit-message", &edit_message, "COMMIT", "reuse and edit message from specified commit"),
        OPT_STRING('C', "reuse-message", &use_message, "COMMIT", "reuse message from specified commit"),
+       OPT_STRING(0, "fixup", &fixup_message, "COMMIT", "use autosquash formatted message to fixup specified commit"),
        OPT_BOOLEAN(0, "reset-author", &renew_authorship, "the commit is authored by me now (used with -C-c/--amend)"),
        OPT_BOOLEAN('s', "signoff", &signoff, "add Signed-off-by:"),
        OPT_FILENAME('t', "template", &template_file, "use specified template file"),
@@ -586,6 +588,16 @@ static int prepare_to_commit(const char *index_file, const char *prefix,
                strbuf_add(&sb, buffer + 2, strlen(buffer + 2));
                hook_arg1 = "commit";
                hook_arg2 = use_message;
+       } else if (fixup_message) {
+               struct pretty_print_context ctx = {0};
+               struct commit *commit;
+               commit = lookup_commit_reference_by_name(fixup_message);
+               if (!commit)
+                       die("could not lookup commit %s", fixup_message);
+               ctx.output_encoding = get_commit_output_encoding();
+               format_commit_message(commit, "fixup! %s\n\n",
+                                     &sb, &ctx);
+               hook_arg1 = "message";
        } else if (!stat(git_path("MERGE_MSG"), &statbuf)) {
                if (strbuf_read_file(&sb, git_path("MERGE_MSG"), 0) < 0)
                        die_errno("could not read MERGE_MSG");
@@ -863,7 +875,7 @@ static int parse_and_validate_options(int argc, const char *argv[],
        if (force_author && renew_authorship)
                die("Using both --reset-author and --author does not make sense");
 
-       if (logfile || message.len || use_message)
+       if (logfile || message.len || use_message || fixup_message)
                use_editor = 0;
        if (edit_flag)
                use_editor = 1;
@@ -883,15 +895,17 @@ static int parse_and_validate_options(int argc, const char *argv[],
                f++;
        if (edit_message)
                f++;
+       if (fixup_message)
+               f++;
        if (logfile)
                f++;
        if (f > 1)
-               die("Only one of -c/-C/-F can be used.");
+               die("Only one of -c/-C/-F/--fixup can be used.");
        if (message.len && f > 0)
-               die("Option -m cannot be combined with -c/-C/-F.");
+               die("Option -m cannot be combined with -c/-C/-F/--fixup.");
        if (edit_message)
                use_message = edit_message;
-       if (amend && !use_message)
+       if (amend && !use_message && !fixup_message)
                use_message = "HEAD";
        if (!use_message && renew_authorship)
                die("--reset-author can be used only with -C, -c or --amend.");