message: don't assume the comment char

The comment char is configurable and we need to provide a way for the
user to specify which comment char they chose for their message.

include/git2/message.h

@@ -29,12 +29,14 @@ GIT_BEGIN_DECL
  *
  * @param message The message to be prettified.
  *
- * @param strip_comments Non-zero to remove lines starting with "#", 0 to
- *     leave them in.
+ * @param strip_comments Non-zero to remove comment lines, 0 to leave them in.
+ *
+ * @param comment_char Comment character. Lines starting with this character
+ * are considered to be comments and removed if `strip_comments` is non-zero.
  *
  * @return 0 or an error code.
  */
-GIT_EXTERN(int) git_message_prettify(git_buf *out, const char *message, int strip_comments);
+GIT_EXTERN(int) git_message_prettify(git_buf *out, const char *message, int strip_comments, char comment_char);
 
 /** @} */
 GIT_END_DECL

src/message.c

@@ -21,7 +21,7 @@ static size_t line_length_without_trailing_spaces(const char *line, size_t len)
 
 /* Greatly inspired from git.git "stripspace" */
 /* see https://github.com/git/git/blob/497215d8811ac7b8955693ceaad0899ecd894ed2/builtin/stripspace.c#L4-67 */
-int git_message_prettify(git_buf *message_out, const char *message, int strip_comments)
+int git_message_prettify(git_buf *message_out, const char *message, int strip_comments, char comment_char)
 {
 	const size_t message_len = strlen(message);
 
@@ -40,7 +40,7 @@ int git_message_prettify(git_buf *message_out, const char *message, int strip_co
 			line_length = message_len - i;
 		}
 
-		if (strip_comments && line_length && message[i] == '#')
+		if (strip_comments && line_length && message[i] == comment_char)
 			continue;
 
 		rtrimmed_line_length = line_length_without_trailing_spaces(message + i, line_length);

tests/object/commit/commitstagedfile.c

@@ -112,7 +112,7 @@ void test_object_commit_commitstagedfile__generate_predictable_object_ids(void)
 	cl_git_pass(git_tree_lookup(&tree, repo, &tree_oid));
 
 	memset(&buffer, 0, sizeof(git_buf));
-	cl_git_pass(git_message_prettify(&buffer, "Initial commit", 0));
+	cl_git_pass(git_message_prettify(&buffer, "Initial commit", 0, '#'));
 
 	cl_git_pass(git_commit_create_v(
 		&commit_oid,

tests/object/message.c

@@ -6,7 +6,7 @@ static void assert_message_prettifying(char *expected_output, char *input, int s
 {
 	git_buf prettified_message = GIT_BUF_INIT;
 
-	git_message_prettify(&prettified_message, input, strip_comments);
+	git_message_prettify(&prettified_message, input, strip_comments, '#');
 	cl_assert_equal_s(expected_output, git_buf_cstr(&prettified_message));
 
 	git_buf_free(&prettified_message);
@@ -175,25 +175,25 @@ void test_object_message__message_prettify(void)
 	git_buf buffer;
 
 	memset(&buffer, 0, sizeof(buffer));
-	cl_git_pass(git_message_prettify(&buffer, "", 0));
+	cl_git_pass(git_message_prettify(&buffer, "", 0, '#'));
 	cl_assert_equal_s(buffer.ptr, "");
 	git_buf_free(&buffer);
-	cl_git_pass(git_message_prettify(&buffer, "", 1));
+	cl_git_pass(git_message_prettify(&buffer, "", 1, '#'));
 	cl_assert_equal_s(buffer.ptr, "");
 	git_buf_free(&buffer);
 
-	cl_git_pass(git_message_prettify(&buffer, "Short", 0));
+	cl_git_pass(git_message_prettify(&buffer, "Short", 0, '#'));
 	cl_assert_equal_s("Short\n", buffer.ptr);
 	git_buf_free(&buffer);
-	cl_git_pass(git_message_prettify(&buffer, "Short", 1));
+	cl_git_pass(git_message_prettify(&buffer, "Short", 1, '#'));
 	cl_assert_equal_s("Short\n", buffer.ptr);
 	git_buf_free(&buffer);
 
-	cl_git_pass(git_message_prettify(&buffer, "This is longer\nAnd multiline\n# with some comments still in\n", 0));
+	cl_git_pass(git_message_prettify(&buffer, "This is longer\nAnd multiline\n# with some comments still in\n", 0, '#'));
 	cl_assert_equal_s(buffer.ptr, "This is longer\nAnd multiline\n# with some comments still in\n");
 	git_buf_free(&buffer);
 
-	cl_git_pass(git_message_prettify(&buffer, "This is longer\nAnd multiline\n# with some comments still in\n", 1));
+	cl_git_pass(git_message_prettify(&buffer, "This is longer\nAnd multiline\n# with some comments still in\n", 1, '#'));
 	cl_assert_equal_s(buffer.ptr, "This is longer\nAnd multiline\n");
 	git_buf_free(&buffer);
 }