From 6e114c786954b11de9884e931e9040cde596bb7e Mon Sep 17 00:00:00 2001
From: Allan Nathanson <42244061+Allan-N@users.noreply.github.com>
Date: Wed, 30 Oct 2024 16:52:41 -0400
Subject: [PATCH] config.c: retain leading whitespace before comments

Configurations loaded with the ast_config_load2() API and later written
out with ast_config_text_file_save2() will have any leading whitespace
stripped away.  The APIs should make reasonable efforts to maintain the
content and formatting of the configuration files.

This change retains any leading whitespace from comment lines that start
with a ";".

Resolves: https://github.com/asterisk/asterisk/issues/970
(cherry picked from commit 4528f5f25a5f4445eec7ebe0a1d9e925b005873b)
---
 main/config.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/main/config.c b/main/config.c
index 3d7bcbe62f..1fa567950e 100644
--- a/main/config.c
+++ b/main/config.c
@@ -2469,6 +2469,18 @@ static struct ast_config *config_text_file_load(const char *database, const char
 								if (!comment) {
 									/* If ; is found, and we are not nested in a comment,
 									   we immediately stop all comment processing */
+									while ((comment_p > new_buf) && isspace(*(comment_p - 1))) {
+										/* To preserve comment formatting we want to include any
+										   whitespace before the ";" */
+										comment_p--;
+									}
+									if ((comment_p != new_buf) && (*comment_p == ' ') && (*(comment_p + 1) == ' ')) {
+										/* If the comment (w/whitespace) does not start in column 1
+										   then, when written out, the preceeding variable/value will
+										   be separated from the comment by two spaces. To preserve
+										   comment formatting we should also take this into account. */
+										comment_p += 2;
+									}
 									if (ast_test_flag(&flags, CONFIG_FLAG_WITHCOMMENTS)) {
 										CB_ADD(&lline_buffer, comment_p);
 									}