From d09cc519bd0c04a0d1ec5bf23ed053c1e596851a Mon Sep 17 00:00:00 2001
From: Christopher Faulet <cfaulet@haproxy.com>
Date: Wed, 24 Mar 2021 14:48:45 +0100
Subject: [PATCH] MINOR: lua: Slightly improve function dumping the lua
 traceback

The separator string is now configurable, passing it as parameter when the
function is called. In addition, the message have been slightly changed to
be a bit more readable.
---
 include/haproxy/hlua.h |  1 +
 src/hlua.c             | 24 +++++++++++-------------
 2 files changed, 12 insertions(+), 13 deletions(-)

diff --git a/include/haproxy/hlua.h b/include/haproxy/hlua.h
index 36629e637..596d096ec 100644
--- a/include/haproxy/hlua.h
+++ b/include/haproxy/hlua.h
@@ -43,6 +43,7 @@
 #define HLUA_INIT(__hlua) do { (__hlua)->T = 0; } while(0)
 
 /* Lua HAProxy integration functions. */
+const char *hlua_traceback(lua_State *L, const char* sep);
 void hlua_ctx_destroy(struct hlua *lua);
 void hlua_init();
 int hlua_post_init();
diff --git a/src/hlua.c b/src/hlua.c
index 962195a60..f3a099e58 100644
--- a/src/hlua.c
+++ b/src/hlua.c
@@ -353,19 +353,17 @@ const char *hlua_get_top_error_string(lua_State *L)
 	return lua_tostring(L, -1);
 }
 
-__LJMP static const char *hlua_traceback(lua_State *L)
+__LJMP const char *hlua_traceback(lua_State *L, const char* sep)
 {
 	lua_Debug ar;
 	int level = 0;
 	struct buffer *msg = get_trash_chunk();
-	int filled = 0;
 
 	while (lua_getstack(L, level++, &ar)) {
 
 		/* Add separator */
-		if (filled)
-			chunk_appendf(msg, ", ");
-		filled = 1;
+		if (b_data(msg))
+			chunk_appendf(msg, "%s", sep);
 
 		/* Fill fields:
 		 * 'S': fills in the fields source, short_src, linedefined, lastlinedefined, and what;
@@ -377,9 +375,9 @@ __LJMP static const char *hlua_traceback(lua_State *L)
 
 		/* Append code localisation */
 		if (ar.currentline > 0)
-			chunk_appendf(msg, "%s:%d ", ar.short_src, ar.currentline);
+			chunk_appendf(msg, "%s:%d: ", ar.short_src, ar.currentline);
 		else
-			chunk_appendf(msg, "%s ", ar.short_src);
+			chunk_appendf(msg, "%s: ", ar.short_src);
 
 		/*
 		 * Get function name
@@ -389,13 +387,13 @@ __LJMP static const char *hlua_traceback(lua_State *L)
 		 * or "main" for main code.
 		 */
 		if (*ar.namewhat != '\0' && ar.name != NULL)  /* is there a name from code? */
-			chunk_appendf(msg, "%s '%s'", ar.namewhat, ar.name);  /* use it */
+			chunk_appendf(msg, "in %s '%s'", ar.namewhat, ar.name);  /* use it */
 
 		else if (*ar.what == 'm')  /* "main", the code is not executed in a function */
-			chunk_appendf(msg, "main chunk");
+			chunk_appendf(msg, "in main chunk");
 
 		else if (*ar.what != 'C')  /* for Lua functions, use <file:line> */
-			chunk_appendf(msg, "C function line %d", ar.linedefined);
+			chunk_appendf(msg, "in function line %d", ar.linedefined);
 
 		else  /* nothing left... */
 			chunk_appendf(msg, "?");
@@ -1350,7 +1348,7 @@ static enum hlua_exec hlua_ctx_resume(struct hlua *lua, int yield_allowed)
 		msg = lua_tostring(lua->T, -1);
 		lua_settop(lua->T, 0); /* Empty the stack. */
 		lua_pop(lua->T, 1);
-		trace = hlua_traceback(lua->T);
+		trace = hlua_traceback(lua->T, ", ");
 		if (msg)
 			lua_pushfstring(lua->T, "[state-id %d] runtime error: %s from %s", lua->state_id, msg, trace);
 		else
@@ -8478,7 +8476,7 @@ int hlua_post_init_state(lua_State *L)
 			msg = lua_tostring(L, -1);
 			lua_settop(L, 0); /* Empty the stack. */
 			lua_pop(L, 1);
-			trace = hlua_traceback(L);
+			trace = hlua_traceback(L, ", ");
 			if (msg)
 				ha_alert("Lua init: %s: '%s' from %s\n", kind, msg, trace);
 			else
@@ -8500,7 +8498,7 @@ int hlua_post_init_state(lua_State *L)
 				kind = "out of memory error";
 			lua_settop(L, 0);
 			lua_pop(L, 1);
-			trace = hlua_traceback(L);
+			trace = hlua_traceback(L, ", ");
 			ha_alert("Lua init: %s: %s\n", kind, trace);
 			return_status = 0;
 			break;