Re: [PATCHv3 3/4] diff: enable indent heuristic by default

[Jeff King]

On Mon, May 01, 2017 at 06:13:44PM -0400, Marc Branchaud wrote:

> From: Stefan Beller 
> 
> The feature was included in v2.11 (released 2016-11-29) and we got no
> negative feedback. Quite the opposite, all feedback we got was positive.
> 
> Turn it on by default. Users who dislike the feature can turn it off
> by setting diff.indentHeuristic (which also configures plumbing commands,
> see prior patches).
> 
> The change to t/t4051-diff-function-context.sh is needed because the
> heuristic shifts the changed hunk in the patch.  To get the same result
> regardless of the heuristic configuration, we modify the test file
> differently:  We insert a completely new line after line 2, instead of
> simply duplicating it.
> 
> Helped-by: Jeff King 
> Signed-off-by: Stefan Beller 
> Signed-off-by: Marc Branchaud 
> 
> ---
> 
> Tested the sed "2a" command's escaping in both Ubuntu 17.04 and FreeBSD 10.3.
> Threw in a little indenting so that it isn't too ugly.

I think that should be fine. The indenting will go into the output, but
we really don't care _what_ that line is, just as long as it's new
content.

> diff --git a/t/t4061-diff-indent.sh b/t/t4061-diff-indent.sh
> index 13d3dc96a..56d7d7760 100755
> --- a/t/t4061-diff-indent.sh
> +++ b/t/t4061-diff-indent.sh
> @@ -153,7 +153,7 @@ test_expect_success 'prepare' '
>  '
>  
>  test_expect_success 'diff: ugly spaces' '
> - git diff old new -- spaces.txt >out &&
> + git diff --no-indent-heuristic old new -- spaces.txt >out &&
>   compare_diff spaces-expect out
>  '

I guess one could argue that most of t4061 should be rewritten. This
fixes the failures that the "ugly" version is no longer the default. But
the tests checking that diff.indentHeuristic=true works are basically
doing nothing (the interesting thing after this patch is that setting it
to false goes back to the ugly output).

I dunno. If we drop the config and options as experiments, then the
whole script basically goes away in favor of checking that the test case
has the non-ugly output. If that's our endgame, it may not be worth
spending too much time refactoring it. But if we're going to keep the
config indefinitely, maybe we should make sure it works.

-Peff

[PATCHv3 3/4] diff: enable indent heuristic by default

[Marc Branchaud]

From: Stefan Beller 

The feature was included in v2.11 (released 2016-11-29) and we got no
negative feedback. Quite the opposite, all feedback we got was positive.

Turn it on by default. Users who dislike the feature can turn it off
by setting diff.indentHeuristic (which also configures plumbing commands,
see prior patches).

The change to t/t4051-diff-function-context.sh is needed because the
heuristic shifts the changed hunk in the patch.  To get the same result
regardless of the heuristic configuration, we modify the test file
differently:  We insert a completely new line after line 2, instead of
simply duplicating it.

Helped-by: Jeff King 
Signed-off-by: Stefan Beller 
Signed-off-by: Marc Branchaud 

---

Tested the sed "2a" command's escaping in both Ubuntu 17.04 and FreeBSD 10.3.
Threw in a little indenting so that it isn't too ugly.

 diff.c   | 2 +-
 t/t4051-diff-function-context.sh | 3 ++-
 t/t4061-diff-indent.sh   | 6 +++---
 3 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/diff.c b/diff.c
index da96577ea..2c47ccb4a 100644
--- a/diff.c
+++ b/diff.c
@@ -27,7 +27,7 @@
 #endif
 
 static int diff_detect_rename_default;
-static int diff_indent_heuristic; /* experimental */
+static int diff_indent_heuristic = 1;
 static int diff_rename_limit_default = 400;
 static int diff_suppress_blank_empty;
 static int diff_use_color_default = -1;
diff --git a/t/t4051-diff-function-context.sh b/t/t4051-diff-function-context.sh
index 6154acb45..3e6b485ec 100755
--- a/t/t4051-diff-function-context.sh
+++ b/t/t4051-diff-function-context.sh
@@ -72,7 +72,8 @@ test_expect_success 'setup' '
 
# overlap function context of 1st change and -u context of 2nd change
grep -v "delete me from hello" <"$dir/hello.c" >file.c &&
-   sed 2p <"$dir/dummy.c" >>file.c &&
+   sed "2a\\
+extra line" <"$dir/dummy.c" >>file.c &&
commit_and_tag changed_hello_dummy file.c &&
 
git checkout initial &&
diff --git a/t/t4061-diff-indent.sh b/t/t4061-diff-indent.sh
index 13d3dc96a..56d7d7760 100755
--- a/t/t4061-diff-indent.sh
+++ b/t/t4061-diff-indent.sh
@@ -153,7 +153,7 @@ test_expect_success 'prepare' '
 '
 
 test_expect_success 'diff: ugly spaces' '
-   git diff old new -- spaces.txt >out &&
+   git diff --no-indent-heuristic old new -- spaces.txt >out &&
compare_diff spaces-expect out
 '
 
@@ -183,7 +183,7 @@ test_expect_success 'diff: --indent-heuristic with 
--histogram' '
 '
 
 test_expect_success 'diff: ugly functions' '
-   git diff old new -- functions.c >out &&
+   git diff --no-indent-heuristic old new -- functions.c >out &&
compare_diff functions-expect out
 '
 
@@ -193,7 +193,7 @@ test_expect_success 'diff: nice functions with 
--indent-heuristic' '
 '
 
 test_expect_success 'blame: ugly spaces' '
-   git blame old..new -- spaces.txt >out-blame &&
+   git blame --no-indent-heuristic old..new -- spaces.txt >out-blame &&
compare_blame spaces-expect out-blame
 '
 
-- 
2.13.0.rc1.15.gf67d331ad