From 088e699c182acf62e96bbdc23e7f44425e256471 Mon Sep 17 00:00:00 2001
From: Jilles Tjoelker <jilles@FreeBSD.org>
Date: Sun, 20 Dec 2009 20:51:20 +0000
Subject: [PATCH] MFC r198173: sh: show more info about syntax errors in
 command substitution: the line number where the command substitution started.
 This applies to both the $() and `` forms but is most useful for `` because
 the other line number is relative to the enclosed text there. (For older
 versions, -v can be used as a workaround.)

---
 bin/sh/parser.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/bin/sh/parser.c b/bin/sh/parser.c
index 54a80a715d0..b898d7a3990 100644
--- a/bin/sh/parser.c
+++ b/bin/sh/parser.c
@@ -1310,6 +1310,7 @@ parsebackq: {
 	struct jmploc *const savehandler = handler;
 	int savelen;
 	int saveprompt;
+	const int bq_startlinno = plinno;
 
 	savepbq = parsebackquote;
 	if (setjmp(jmploc.loc)) {
@@ -1317,6 +1318,10 @@ parsebackq: {
 			ckfree(str);
 		parsebackquote = 0;
 		handler = savehandler;
+		if (exception == EXERROR) {
+			startlinno = bq_startlinno;
+			synerror("Error in command substitution");
+		}
 		longjmp(handler->loc, 1);
 	}
 	INTOFF;