merge: allow reading the merge commit message from a file

This is consistent with `git commit` which, like `git merge`, supports passing the commit message via `-m <msg>` and, unlike `git merge` before this patch, via `-F <file>`. It is useful to allow this for scripted use, or for the upcoming patch to allow (re-)creating octopus merges in `git rebase --rebase-merges`. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Johannes Schindelin committed Dec 22, 2017 at 15:10 UTC 920f22e6bc2ddc28b1d70eb8167fe17f0f1601eb
2 files changed +41 -1
Documentation/git-merge.txt
+9 -1
@@ -12,7 +12,7 @@ SYNOPSIS
12 'git merge' [-n] [--stat] [--no-commit] [--squash] [--[no-]edit]
13 [-s <strategy>] [-X <strategy-option>] [-S[<keyid>]]
14 [--[no-]allow-unrelated-histories]
15 - [--[no-]rerere-autoupdate] [-m <msg>] [<commit>...]
15 + [--[no-]rerere-autoupdate] [-m <msg>] [-F <file>] [<commit>...]
16 'git merge' --abort
17 'git merge' --continue
18
@@ -75,6 +75,14 @@ The 'git fmt-merge-msg' command can be
75 used to give a good default for automated 'git merge'
76 invocations. The automated message can include the branch description.
77
78 +-F <file>::
79 +--file=<file>::
80 + Read the commit message to be used for the merge commit (in
81 + case one is created).
82 ++
83 +If `--log` is specified, a shortlog of the commits being merged
84 +will be appended to the specified message.
85 +
86 --[no-]rerere-autoupdate::
87 Allow the rerere mechanism to update the index with the
88 result of auto-conflict resolution if possible.
builtin/merge.c
+32
@@ -111,6 +111,35 @@ static int option_parse_message(const struct option *opt,
111 return 0;
112 }
113
114 +static int option_read_message(struct parse_opt_ctx_t *ctx,
115 + const struct option *opt, int unset)
116 +{
117 + struct strbuf *buf = opt->value;
118 + const char *arg;
119 +
120 + if (unset)
121 + BUG("-F cannot be negated");
122 +
123 + if (ctx->opt) {
124 + arg = ctx->opt;
125 + ctx->opt = NULL;
126 + } else if (ctx->argc > 1) {
127 + ctx->argc--;
128 + arg = *++ctx->argv;
129 + } else
130 + return opterror(opt, "requires a value", 0);
131 +
132 + if (buf->len)
133 + strbuf_addch(buf, '\n');
134 + if (ctx->prefix && !is_absolute_path(arg))
135 + arg = prefix_filename(ctx->prefix, arg);
136 + if (strbuf_read_file(buf, arg, 0) < 0)
137 + return error(_("could not read file '%s'"), arg);
138 + have_message = 1;
139 +
140 + return 0;
141 +}
142 +
143 static struct strategy *get_strategy(const char *name)
144 {
145 int i;
@@ -228,6 +257,9 @@ static struct option builtin_merge_options[] = {
257 OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
258 N_("merge commit message (for a non-fast-forward merge)"),
259 option_parse_message),
260 + { OPTION_LOWLEVEL_CALLBACK, 'F', "file", &merge_msg, N_("path"),
261 + N_("read message from file"), PARSE_OPT_NONEG,
262 + (parse_opt_cb *) option_read_message },
263 OPT__VERBOSITY(&verbosity),
264 OPT_BOOL(0, "abort", &abort_current_merge,
265 N_("abort the current in-progress merge")),