diff: fix a double off-by-one with --ignore-space-at-eol

When comparing two lines, ignoring any whitespace at the end, we first
try to match as many bytes as possible and break out of the loop only
upon mismatch, to let the remainder be handled by the code shared with
the other whitespace-ignoring code paths.

When comparing the bytes, however, we incremented the counters always,
even if the bytes did not match. And because we fall through to  the
space-at-eol handling at that point, it is as if that mismatch never
happened.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/t/t4033-diff-patience.sh b/t/t4033-diff-patience.sh
index 5f0d0b164c328b06b4b46139e28a82b98ab8be1b..113304dc596034ff9bfaac65b2ff896b6a181dca 100755 (executable)
--- a/t/t4033-diff-patience.sh
+++ b/t/t4033-diff-patience.sh
@@ -5,7 +5,7 @@ test_description='patience diff algorithm'
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-diff-alternative.sh
 
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-diff-alternative.sh
 

-test_expect_failure '--ignore-space-at-eol with a single appended character' '
+test_expect_success '--ignore-space-at-eol with a single appended character' '

        printf "a\nb\nc\n" >pre &&
        printf "a\nbX\nc\n" >post &&
        test_must_fail git diff --no-index \
        printf "a\nb\nc\n" >pre &&
        printf "a\nbX\nc\n" >post &&
        test_must_fail git diff --no-index \

diff --git a/xdiff/xpatience.c b/xdiff/xpatience.c
index 04e1a1ab2a863814df3b9a91d4e854704d47f3f5..a613efc7034bc0dc45bf13428c819701f044323d 100644 (file)
--- a/xdiff/xpatience.c
+++ b/xdiff/xpatience.c
@@ -1,6 +1,6 @@
 /*
  *  LibXDiff by Davide Libenzi ( File Differential Library )
 /*
  *  LibXDiff by Davide Libenzi ( File Differential Library )

- *  Copyright (C) 2003-2009 Davide Libenzi, Johannes E. Schindelin
+ *  Copyright (C) 2003-2016 Davide Libenzi, Johannes E. Schindelin

  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public
  *
  *  This library is free software; you can redistribute it and/or
  *  modify it under the terms of the GNU Lesser General Public

diff --git a/xdiff/xutils.c b/xdiff/xutils.c
index 62cb23dfd37743e4985655998ccabd56db160233..027192a1c7f12214c0ff6787296769ce708ba407 100644 (file)
--- a/xdiff/xutils.c
+++ b/xdiff/xutils.c
@@ -200,8 +200,10 @@ int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags)
                                return 0;
                }
        } else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL) {
                                return 0;
                }
        } else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL) {

-               while (i1 < s1 && i2 < s2 && l1[i1++] == l2[i2++])
-                       ; /* keep going */
+               while (i1 < s1 && i2 < s2 && l1[i1] == l2[i2]) {
+                       i1++;
+                       i2++;
+               }

        }
 
        /*
        }
 
        /*