[PATCH] Display author and committer after "git commit"

[Adam Megacz <adam@megacz.com>]

Display author (name, email, date) and committer (name, email, date)
after creating a new commit to ensure that the user is alerted in the
event that they are set in an undesirable manner.

This patch seeks to accomplish the following goal: all data included
in the commit which are sha1-protected (and therefore immutable) are
either taken from the working tree or else displayed to the user for
sanity checking purposes.  Since the author/committer information is
immutable and not taken from the working tree, achieving the goal
above requires printing out the author/committer.  The short window of
time after committing a patch and before propagating it is the last
opportunity to modify the data (by deleting and recreating the commit).

This patch is not necessarily meant for inclusion verbatim; it's more
of a starting point for discussion.
---
 commit.h   |    2 ++
 log-tree.c |   15 +++++++++++++++
 pretty.c   |   23 ++++++++++++++++++-----
 3 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/commit.h b/commit.h
index e5332ef..e4222b0 100644
--- a/commit.h
+++ b/commit.h
@@ -59,6 +59,8 @@ enum cmit_fmt {
 	CMIT_FMT_ONELINE,
 	CMIT_FMT_EMAIL,
 	CMIT_FMT_USERFORMAT,
+        CMIT_FMT_COMMITTER_AND_DATE,
+        CMIT_FMT_AUTHOR_AND_DATE,
 
 	CMIT_FMT_UNSPECIFIED,
 };
diff --git a/log-tree.c b/log-tree.c
index 0fdf159..7b399b8 100644
--- a/log-tree.c
+++ b/log-tree.c
@@ -160,6 +160,20 @@ static void append_signoff(struct strbuf *sb, const char *signoff)
 	strbuf_addch(sb, '\n');
 }
 
+static void append_metadata(struct strbuf *sb,
+                            struct commit *commit,
+                            const struct pretty_print_context *ctx)
+{
+
+	strbuf_addch(sb, '\n');
+	strbuf_addstr(sb, " Author:     ");
+        pretty_print_commit(CMIT_FMT_AUTHOR_AND_DATE, commit, sb, ctx);
+
+	strbuf_addch(sb, '\n');
+	strbuf_addstr(sb, " Committer:  ");
+        pretty_print_commit(CMIT_FMT_COMMITTER_AND_DATE, commit, sb, ctx);
+}
+
 static unsigned int digits_in_number(unsigned int number)
 {
 	unsigned int i = 10, result = 1;
@@ -414,6 +428,7 @@ void show_log(struct rev_info *opt)
 	ctx.reflog_info = opt->reflog_info;
 	pretty_print_commit(opt->commit_format, commit, &msgbuf, &ctx);
 
+        append_metadata(&msgbuf, commit, &ctx);
 	if (opt->add_signoff)
 		append_signoff(&msgbuf, opt->add_signoff);
 	if (opt->show_log_size) {
diff --git a/pretty.c b/pretty.c
index 8f5bd1a..2458509 100644
--- a/pretty.c
+++ b/pretty.c
@@ -1028,16 +1028,26 @@ void pretty_print_commit(enum cmit_fmt fmt, const struct commit *commit,
 	int need_8bit_cte = context->need_8bit_cte;
 
 	if (fmt == CMIT_FMT_USERFORMAT) {
-		format_commit_message(commit, user_format, sb, context);
+                format_commit_message(commit, user_format, sb, context);
 		return;
 	}
+        if (fmt == CMIT_FMT_COMMITTER_AND_DATE) {
+                format_commit_message(commit, "%cn <%ce> %cd", sb, context);
+                return;
+        }
+        if (fmt == CMIT_FMT_AUTHOR_AND_DATE) {
+                format_commit_message(commit, "%an <%ae> %ad", sb, context);
+                return;
+        }
 
 	reencoded = reencode_commit_message(commit, &encoding);
 	if (reencoded) {
 		msg = reencoded;
 	}
 
-	if (fmt == CMIT_FMT_ONELINE || fmt == CMIT_FMT_EMAIL)
+
+	if (fmt == CMIT_FMT_ONELINE || fmt == CMIT_FMT_EMAIL ||
+            fmt == CMIT_FMT_COMMITTER_AND_DATE || CMIT_FMT_AUTHOR_AND_DATE)
 		indent = 0;
 
 	/*
@@ -1078,12 +1088,14 @@ void pretty_print_commit(enum cmit_fmt fmt, const struct commit *commit,
 			      context->after_subject, encoding, need_8bit_cte);
 
 	beginning_of_body = sb->len;
-	if (fmt != CMIT_FMT_ONELINE)
+	if (fmt != CMIT_FMT_ONELINE &&
+            fmt != CMIT_FMT_COMMITTER_AND_DATE && fmt != CMIT_FMT_AUTHOR_AND_DATE)
 		pp_remainder(fmt, &msg, sb, indent);
 	strbuf_rtrim(sb);
 
 	/* Make sure there is an EOLN for the non-oneline case */
-	if (fmt != CMIT_FMT_ONELINE)
+	if (fmt != CMIT_FMT_ONELINE &&
+            fmt != CMIT_FMT_COMMITTER_AND_DATE && fmt != CMIT_FMT_AUTHOR_AND_DATE)
 		strbuf_addch(sb, '\n');
 
 	/*
@@ -1094,7 +1106,8 @@ void pretty_print_commit(enum cmit_fmt fmt, const struct commit *commit,
 	if (fmt == CMIT_FMT_EMAIL && sb->len <= beginning_of_body)
 		strbuf_addch(sb, '\n');
 
-	if (fmt != CMIT_FMT_ONELINE)
+	if (fmt != CMIT_FMT_ONELINE &&
+            fmt != CMIT_FMT_COMMITTER_AND_DATE && fmt != CMIT_FMT_AUTHOR_AND_DATE)
 		get_commit_notes(commit, sb, encoding,
 				 NOTES_SHOW_HEADER | NOTES_INDENT);
 
-- 
1.6.4.4