diff: add --ignore-blank-lines option
authorAntoine Pelisse <apelisse@gmail.com>
Wed, 19 Jun 2013 18:46:07 +0000 (20:46 +0200)
committerJunio C Hamano <gitster@pobox.com>
Wed, 19 Jun 2013 22:17:45 +0000 (15:17 -0700)
The goal of the patch is to introduce the GNU diff
-B/--ignore-blank-lines as closely as possible. The short option is not
available because it's already used for "break-rewrites".

When this option is used, git-diff will not create hunks that simply
add or remove empty lines, but will still show empty lines
addition/suppression if they are close enough to "valuable" changes.

There are two differences between this option and GNU diff -B option:
- GNU diff doesn't have "--inter-hunk-context", so this must be handled
- The following sequence looks like a bug (context is displayed twice):

$ seq 5 >file1
$ cat <<EOF >file2
change
1
2

3
4
5
change
EOF
$ diff -u -B file1 file2
--- file1 2013-06-08 22:13:04.471517834 +0200
+++ file2 2013-06-08 22:13:23.275517855 +0200
@@ -1,5 +1,7 @@
+change
1
2
+
3
4
5
@@ -3,3 +5,4 @@
3
4
5
+change

So here is a more thorough description of the option:
- real changes are interesting
- blank lines that are close enough (less than context size) to
interesting changes are considered interesting (recursive definition)
- "context" lines are used around each hunk of interesting changes
- If two hunks are separated by less than "inter-hunk-context", they
will be merged into one.

The implementation does the "interesting changes selection" in a single
pass.

Signed-off-by: Antoine Pelisse <apelisse@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
No differences found