commit: Show committer if automatic

To warn the user in case he/she might be using an unintended
committer identity.

Signed-off-by: Santi Béjar <sbejar@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-commit.c

@@ -446,6 +446,7 @@ static int prepare_to_commit(const char *index_file, const char *prefix)
 	FILE *fp;
 	const char *hook_arg1 = NULL;
 	const char *hook_arg2 = NULL;
+	int ident_shown = 0;
 
 	if (!no_verify && run_hook(index_file, "pre-commit", NULL))
 		return 0;
@@ -527,6 +528,8 @@ static int prepare_to_commit(const char *index_file, const char *prefix)
 
 	determine_author_info();
 
+	/* This checks if committer ident is explicitly given */
+	git_committer_info(0);
 	if (use_editor) {
 		char *author_ident;
 		const char *committer_ident;
@@ -558,12 +561,22 @@ static int prepare_to_commit(const char *index_file, const char *prefix)
 					   getenv("GIT_COMMITTER_EMAIL"));
 		if (strcmp(author_ident, committer_ident))
 			fprintf(fp,
-				"#\n"
-				"# Author:    %s\n"
-				"#\n",
+				"%s"
+				"# Author:    %s\n",
+				ident_shown++ ? "" : "#\n",
 				author_ident);
 		free(author_ident);
 
+		if (!user_ident_explicitly_given)
+			fprintf(fp,
+				"%s"
+				"# Committer: %s\n",
+				ident_shown++ ? "" : "#\n",
+				committer_ident);
+
+		if (ident_shown)
+			fprintf(fp, "#\n");
+
 		saved_color_setting = wt_status_use_color;
 		wt_status_use_color = 0;
 		commitable = run_status(fp, index_file, prefix, 1);

cache.h

@@ -719,6 +719,7 @@ extern int config_error_nonbool(const char *);
 #define MAX_GITNAME (1000)
 extern char git_default_email[MAX_GITNAME];
 extern char git_default_name[MAX_GITNAME];
+extern int user_ident_explicitly_given;
 
 extern const char *git_commit_encoding;
 extern const char *git_log_output_encoding;

config.c

@@ -443,13 +443,17 @@ int git_default_config(const char *var, const char *value)
 		if (!value)
 			return config_error_nonbool(var);
 		strlcpy(git_default_name, value, sizeof(git_default_name));
+		if (git_default_email[0])
+			user_ident_explicitly_given = 1;
 		return 0;
 	}
 
 	if (!strcmp(var, "user.email")) {
 		if (!value)
 			return config_error_nonbool(var);
 		strlcpy(git_default_email, value, sizeof(git_default_email));
+		if (git_default_name[0])
+			user_ident_explicitly_given = 1;
 		return 0;
 	}
 

environment.c

@@ -11,6 +11,7 @@
 
 char git_default_email[MAX_GITNAME];
 char git_default_name[MAX_GITNAME];
+int user_ident_explicitly_given;
 int trust_executable_bit = 1;
 int quote_path_fully = 1;
 int has_symlinks = 1;

ident.c

@@ -250,6 +250,9 @@ const char *git_author_info(int flag)
 
 const char *git_committer_info(int flag)
 {
+	if (getenv("GIT_COMMITTER_NAME") &&
+	    getenv("GIT_COMMITTER_EMAIL"))
+		user_ident_explicitly_given = 1;
 	return fmt_ident(getenv("GIT_COMMITTER_NAME"),
 			 getenv("GIT_COMMITTER_EMAIL"),
 			 getenv("GIT_COMMITTER_DATE"),

t/t7502-commit.sh

@@ -166,6 +166,21 @@ test_expect_success 'author different from committer' '
 	test_cmp expect actual
 '
 
+sed -i '$d' expect
+echo "# Committer:
+#" >> expect
+unset GIT_COMMITTER_EMAIL
+unset GIT_COMMITTER_NAME
+
+test_expect_success 'committer is automatic' '
+
+	echo >>negative &&
+	git commit -e -m "sample"
+	head -n 8 .git/COMMIT_EDITMSG |	\
+	sed "s/^# Committer: .*/# Committer:/" >actual &&
+	test_cmp expect actual
+'
+
 pwd=`pwd`
 cat >> .git/FAKE_EDITOR << EOF
 #! /bin/sh