>From e0c1f772d505d40166dc308706baecedc23efdab Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A1draig=20Brady?= <address@hidden>
Date: Sun, 13 Dec 2015 02:14:06 +0000
Subject: [PATCH] sort: fix --debug marking for -b -k1.x

We were erroneously skipping blanks in the marked comparison
_after_ the key start offset was applied.
* src/sort.c (debug_keys): Don't skip starting blanks
if already handled by begfield().
* tests/misc/sort-debug-keys.sh: Add a test case.
* NEWS: Mention the bug fix.
Fixes http://bugs.gnu.org/22155
---
 NEWS                          | 4 ++++
 src/sort.c                    | 3 ++-
 tests/misc/sort-debug-keys.sh | 7 +++++++
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/NEWS b/NEWS
index 2988146..367fb63 100644
--- a/NEWS
+++ b/NEWS
@@ -15,6 +15,10 @@ GNU coreutils NEWS                                    -*- outline -*-
   shred again uses defined patterns for all iteration counts.
   [bug introduced in coreutils-5.93]
 
+  sort --debug -b now correctly marks the matching extents for keys
+  that specify an offset for the first field.
+  [bug introduced with the --debug feature in coreutils-8.6]
+
 ** New commands
 
   base32 is added to complement the existing base64 command,
diff --git a/src/sort.c b/src/sort.c
index 399b964..29a3617 100644
--- a/src/sort.c
+++ b/src/sort.c
@@ -2274,7 +2274,8 @@ debug_key (struct line const *line, struct keyfield const *key)
       if (key->eword != SIZE_MAX)
         lim = limfield (line, key);
 
-      if (key->skipsblanks || key->month || key_numeric (key))
+      if ((key->skipsblanks && key->sword == SIZE_MAX)
+          || key->month || key_numeric (key))
         {
           char saved = *lim;
           *lim = '\0';
diff --git a/tests/misc/sort-debug-keys.sh b/tests/misc/sort-debug-keys.sh
index a0a2874..fadd19c 100755
--- a/tests/misc/sort-debug-keys.sh
+++ b/tests/misc/sort-debug-keys.sh
@@ -238,6 +238,10 @@ A>chr10
      ^ no match for key
 B>chr1
      ^ no match for key
+1 2
+ __
+1 3
+ __
 EOF
 
 (
@@ -282,6 +286,9 @@ printf '\0\ta\n' | sort -s -k2b,2 --debug | tr -d '\0'
 
 # Check that key end before key start is not underlined
 printf 'A\tchr10\nB\tchr1\n' | sort -s -k2.4b,2.3n --debug
+
+# Ensure that -b applied before -k offsets
+printf '1 2\n1 3\n' | sort -s -k1.2b --debug
 ) > out
 
 compare exp out || fail=1
-- 
2.5.0