Merge branch 'jk/warn-author-committer-after-commit'

* jk/warn-author-committer-after-commit:
  user_ident_sufficiently_given(): refactor the logic to be usable from elsewhere
  commit.c::print_summary: do not release the format string too early
  commit: allow suppression of implicit identity advice
  commit: show interesting ident information in summary
  strbuf: add strbuf_addbuf_percentquote
  strbuf_expand: convert "%%" to "%"

Conflicts:
	builtin-commit.c
	ident.c

Documentation/config.txt

@@ -130,6 +130,10 @@ advice.*::
 		Advice shown when linkgit:git-merge[1] refuses to
 		merge to avoid overwritting local changes.
 		Default: true.
+	implicitIdentity::
+		Advice on how to set your identity configuration when
+		your information is guessed from the system username and
+		domain name. Default: true.
 --
 
 core.fileMode::

Documentation/pretty-formats.txt

@@ -134,6 +134,7 @@ The placeholders are:
 - '%C(...)': color specification, as described in color.branch.* config option
 - '%m': left, right or boundary mark
 - '%n': newline
+- '%%': a raw '%'
 - '%x00': print a byte from a hex code
 - '%w([<w>[,<i1>[,<i2>]]])': switch line wrapping, like the -w option of
   linkgit:git-shortlog[1].

Documentation/technical/api-strbuf.txt

@@ -199,6 +199,10 @@ character if the letter `n` appears after a `%`.  The function returns
 the length of the placeholder recognized and `strbuf_expand()` skips
 over it.
 +
+The format `%%` is automatically expanded to a single `%` as a quoting
+mechanism; callers do not need to handle the `%` placeholder themselves,
+and the callback function will not be invoked for this placeholder.
++
 All other characters (non-percent and not skipped ones) are copied
 verbatim to the strbuf.  If the callback returned zero, meaning that the
 placeholder is unknown, then the percent sign is copied, too.
@@ -214,6 +218,13 @@ which can be used by the programmer of the callback as she sees fit.
 	placeholder and replacement string.  The array needs to be
 	terminated by an entry with placeholder set to NULL.
 
+`strbuf_addbuf_percentquote`::
+
+	Append the contents of one strbuf to another, quoting any
+	percent signs ("%") into double-percents ("%%") in the
+	destination. This is useful for literal data to be fed to either
+	strbuf_expand or to the *printf family of functions.
+
 `strbuf_addf`::
 
 	Add a formatted string to the buffer.

advice.c

@@ -3,6 +3,7 @@
 int advice_push_nonfastforward = 1;
 int advice_status_hints = 1;
 int advice_commit_before_merge = 1;
+int advice_implicit_identity = 1;
 
 static struct {
 	const char *name;
@@ -11,6 +12,7 @@ static struct {
 	{ "pushnonfastforward", &advice_push_nonfastforward },
 	{ "statushints", &advice_status_hints },
 	{ "commitbeforemerge", &advice_commit_before_merge },
+	{ "implicitidentity", &advice_implicit_identity },
 };
 
 int git_default_advice_config(const char *var, const char *value)

advice.h

@@ -4,6 +4,7 @@
 extern int advice_push_nonfastforward;
 extern int advice_status_hints;
 extern int advice_commit_before_merge;
+extern int advice_implicit_identity;
 
 int git_default_advice_config(const char *var, const char *value);
 

builtin-commit.c

@@ -36,7 +36,20 @@ static const char * const builtin_status_usage[] = {
 	NULL
 };
 
+static const char implicit_ident_advice[] =
+"Your name and email address were configured automatically based\n"
+"on your username and hostname. Please check that they are accurate.\n"
+"You can suppress this message by setting them explicitly:\n"
+"\n"
+"    git config --global user.name Your Name\n"
+"    git config --global user.email you@example.com\n"
+"\n"
+"If the identity used for this commit is wrong, you can fix it with:\n"
+"\n"
+"    git commit --amend --author='Your Name <you@example.com>'\n";
+
 static unsigned char head_sha1[20];
+
 static char *use_message_buffer;
 static const char commit_editmsg[] = "COMMIT_EDITMSG";
 static struct lock_file index_lock; /* real index */
@@ -1055,16 +1068,38 @@ static void print_summary(const char *prefix, const unsigned char *sha1)
 {
 	struct rev_info rev;
 	struct commit *commit;
-	static const char *format = "format:%h] %s";
+	struct strbuf format = STRBUF_INIT;
 	unsigned char junk_sha1[20];
 	const char *head = resolve_ref("HEAD", junk_sha1, 0, NULL);
+	struct pretty_print_context pctx = {0};
+	struct strbuf author_ident = STRBUF_INIT;
+	struct strbuf committer_ident = STRBUF_INIT;
 
 	commit = lookup_commit(sha1);
 	if (!commit)
 		die("couldn't look up newly created commit");
 	if (!commit || parse_commit(commit))
 		die("could not parse newly created commit");
 
+	strbuf_addstr(&format, "format:%h] %s");
+
+	format_commit_message(commit, "%an <%ae>", &author_ident, &pctx);
+	format_commit_message(commit, "%cn <%ce>", &committer_ident, &pctx);
+	if (strbuf_cmp(&author_ident, &committer_ident)) {
+		strbuf_addstr(&format, "\n Author: ");
+		strbuf_addbuf_percentquote(&format, &author_ident);
+	}
+	if (!user_ident_sufficiently_given()) {
+		strbuf_addstr(&format, "\n Committer: ");
+		strbuf_addbuf_percentquote(&format, &committer_ident);
+		if (advice_implicit_identity) {
+			strbuf_addch(&format, '\n');
+			strbuf_addstr(&format, implicit_ident_advice);
+		}
+	}
+	strbuf_release(&author_ident);
+	strbuf_release(&committer_ident);
+
 	init_revisions(&rev, prefix);
 	setup_revisions(0, NULL, &rev, NULL);
 
@@ -1075,7 +1110,7 @@ static void print_summary(const char *prefix, const unsigned char *sha1)
 
 	rev.verbose_header = 1;
 	rev.show_root_diff = 1;
-	get_commit_format(format, &rev);
+	get_commit_format(format.buf, &rev);
 	rev.always_show_header = 0;
 	rev.diffopt.detect_rename = 1;
 	rev.diffopt.rename_limit = 100;
@@ -1094,10 +1129,11 @@ static void print_summary(const char *prefix, const unsigned char *sha1)
 		struct pretty_print_context ctx = {0};
 		struct strbuf buf = STRBUF_INIT;
 		ctx.date_mode = DATE_NORMAL;
-		format_commit_message(commit, format + 7, &buf, &ctx);
+		format_commit_message(commit, format.buf + 7, &buf, &ctx);
 		printf("%s\n", buf.buf);
 		strbuf_release(&buf);
 	}
+	strbuf_release(&format);
 }
 
 static int git_commit_config(const char *k, const char *v, void *cb)

daemon.c

@@ -147,7 +147,6 @@ static char *path_ok(char *directory)
 			{ "IP", ip_address },
 			{ "P", tcp_port },
 			{ "D", directory },
-			{ "%", "%" },
 			{ NULL }
 		};
 

strbuf.c

@@ -220,6 +220,12 @@ void strbuf_expand(struct strbuf *sb, const char *format, expand_fn_t fn,
 			break;
 		format = percent + 1;
 
+		if (*format == '%') {
+			strbuf_addch(sb, '%');
+			format++;
+			continue;
+		}
+
 		consumed = fn(sb, format, context);
 		if (consumed)
 			format += consumed;
@@ -244,6 +250,17 @@ size_t strbuf_expand_dict_cb(struct strbuf *sb, const char *placeholder,
 	return 0;
 }
 
+void strbuf_addbuf_percentquote(struct strbuf *dst, const struct strbuf *src)
+{
+	int i, len = src->len;
+
+	for (i = 0; i < len; i++) {
+		if (src->buf[i] == '%')
+			strbuf_addch(dst, '%');
+		strbuf_addch(dst, src->buf[i]);
+	}
+}
+
 size_t strbuf_fread(struct strbuf *sb, size_t size, FILE *f)
 {
 	size_t res;

strbuf.h

@@ -115,6 +115,7 @@ struct strbuf_expand_dict_entry {
 	const char *value;
 };
 extern size_t strbuf_expand_dict_cb(struct strbuf *sb, const char *placeholder, void *context);
+extern void strbuf_addbuf_percentquote(struct strbuf *dst, const struct strbuf *src);
 
 __attribute__((format (printf,2,3)))
 extern void strbuf_addf(struct strbuf *sb, const char *fmt, ...);

t/t6006-rev-list-format.sh

@@ -19,6 +19,13 @@ test_cmp expect.$1 output.$1
 "
 }
 
+test_format percent %%h <<'EOF'
+commit 131a310eb913d107dd3c09a65d1651175898735d
+%h
+commit 86c75cfd708a0e5868dc876ed5b8bb66c80b4873
+%h
+EOF
+
 test_format hash %H%n%h <<'EOF'
 commit 131a310eb913d107dd3c09a65d1651175898735d
 131a310eb913d107dd3c09a65d1651175898735d

t/t7501-commit.sh

@@ -117,7 +117,11 @@ test_expect_success \
 test_expect_success \
 	"overriding author from command line" \
 	"echo 'gak' >file && \
-	 git commit -m 'author' --author 'Rubber Duck <rduck@convoy.org>' -a"
+	 git commit -m 'author' --author 'Rubber Duck <rduck@convoy.org>' -a >output 2>&1"
+
+test_expect_success \
+	"commit --author output mentions author" \
+	"grep Rubber.Duck output"
 
 test_expect_success PERL \
 	"interactive add" \