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| author |  Phillip Wood <phillip.wood@dunelm.org.uk> | 2021-05-04 09:27:34 +0000 |
|---|---|---|
| committer |  Junio C Hamano <gitster@pobox.com> | 2021-05-05 18:53:42 +0900 |
| commit | 0324e8fc6b297c9e61745dc4e7d110780334157d (patch) | |
| tree | 1fd1960912ae578b9ebd1a26b35d7208ba89befb /t | |
| parent | Git 2.31.1 (diff) | |
| download | tgif-0324e8fc6b297c9e61745dc4e7d110780334157d.tar.xz | |
word diff: handle zero length matches
If find_word_boundaries() encounters a zero length match (which can be
caused by matching a newline or using '*' instead of '+' in the regex)
we stop splitting the input into words which generates an inaccurate
diff. To fix this increment the start point when there is a zero
length match and try a new match. This is safe as posix regular
expressions always return the longest available match so a zero length
match means there are no longer matches available from the current
position.
Commit bf82940dbf1 (color-words: enable REG_NEWLINE to help user,
2009-01-17) prevented matching newlines in negated character classes
but it is still possible for the user to have an explicit newline
match in the regex which could cause a zero length match.
One could argue that having explicit newline matches or using '*'
rather than '+' are user errors but it seems to be better to work
round them than produce inaccurate diffs.
Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 't')
| -rwxr-xr-x | t/t4034-diff-words.sh | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/t/t4034-diff-words.sh b/t/t4034-diff-words.sh index 56f1e62a97..17ceba9f61 100755 --- a/t/t4034-diff-words.sh +++ b/t/t4034-diff-words.sh @@ -184,6 +184,11 @@ test_expect_success 'word diff with a regular expression' ' word_diff --color-words="[a-z]+" ' +test_expect_success 'word diff with zero length matches' ' + cp expect.letter-runs-are-words expect && + word_diff --color-words="[a-z${LF}]*" +' + test_expect_success 'set up a diff driver' ' git config diff.testdriver.wordRegex "[^[:space:]]" && cat <<-\EOF >.gitattributes |