RFC patchuserdiff: added support for diffing shell scripts

Signed-off-by: Kapil Jain <jkapil.cs@gmail.com>
---

The test written does not pass, imo there's some problem with the regex part. please let me know about the fault.

 t/t4034-diff-words.sh | 2 ++
 t/t4034/shell/expect  | 6 ++++++
 t/t4034/shell/post    | 1 +
 t/t4034/shell/pre     | 1 +
 userdiff.c            | 7 +++++++
 5 files changed, 17 insertions(+)
 create mode 100644 t/t4034/shell/expect
 create mode 100644 t/t4034/shell/post
 create mode 100644 t/t4034/shell/pre

On Fri, Mar 22, 2019 at 5:08 PM Kapil Jain <jkapil.cs@gmail.com> wrote:

To save some work by people who could help you, it might be a good idea to show the output of the failing test, for example the output of `./t4034-diff-words.sh -i -v` or `./t4034-diff-words.sh -i -v -x`.

On Sun, Mar 24, 2019 at 1:34 AM Christian Couder <christian.couder@gmail.com> wrote:

Looks like i just needed to know about -i, -v and -x switches, they helped in debugging. The problem was with the expect file. It is resolved now.

Thanks, will be resubmitting with updated expect file.

is the parser used to parse the expect file specific to git ? or is it some general one ?

On Sun, Mar 24, 2019 at 9:04 AM Kapil Jain <jkapil.cs@gmail.com> wrote:

Great!

It looks like you sent "[GSoC][RFC/PATCH 2/2] userdiff: added shell script support, clears test". I think though that it should have been named "[GSoC][RFC/PATCH v2] userdiff: added shell script support, clears test".

"2/2" means that it is patch number 2 in a patch series that has 2 patches (which should be marked with "1/2" and "2/2"). When resubmitting an already submitted patch (or patch series) we ask for a version number like "v2", "v3", so that we can know that it has already been submitted.

`git format-patch -v 2 ...` will automatically add "v2".

The test_language_driver() function used to test the regexps is defined in t4034-diff-words.sh and it calls the word_diff() function (also defined in t4034-diff-words.sh) which is:

word_diff () {
    test_must_fail git diff --no-index "$@" pre post >output &&
    test_decode_color <output >output.decrypted &&
    test_cmp expect output.decrypted
}

So it uses test_decode_color() and test_cmp() that are defined in t/test-lib-functions.sh. test_cmp() in turn is defined using GIT_TEST_CMP which is usually either "diff -u" or "diff -c".

On Sun, Mar 24, 2019 at 2:49 PM Christian Couder <christian.couder@gmail.com> wrote:

Thanks.

please provide some insights on the regex mentioned below:

+
+PATTERNS("shell",
+  /* Function Names */
+  "([A-Za-z_][A-Za-z0-9_]*)[[:space:]]*\\([[:space:]]*\\)[[:space:]]*\\{",
+  /* Words */
+  "([$#@A-Za-z_\"\'][$#@A-Za-z0-9_\"\']*)"),
+

reference mail: https://public-inbox.org/git/20190324084523.8744-1-jkapil.cs@gmail.com/. please let me know if the regex is not self explanatory.

On 03/24, Kapil Jain wrote:

I had previously mentioned that this project was attempted already in my email at [*1*]. Did you take a look at the thread I linked to there, and the regex used? I still feel like that previous experience is something you could learn from.

But that said, I think your assumption in the other email that the output should be

[-$TEST_DIRECTORY-] {+$TEST_DIR+}

might not be correct. The tests are using 'git diff --word-diff=color', rather than 'git diff --word-diff=plain'. Only the latter would add the [- -] and {+ +} around the changed words, while the former adds the color, which the tests are testing for.

*1*: https://public-inbox.org/git/20190315230515.GJ16414@hank.intra.tgummerer.com/

On Fri, Mar 29, 2019 at 3:00 AM Thomas Gummerer <t.gummerer@gmail.com> wrote:

I saw it, and the regex i have used is a little different from that one.

This makes sense, i will write more tests for this.

On 03/29, Kapil Jain wrote:

Right, so one thing you should definitely do is to compare the regex there and the regex you have, and understand why there are differences when they are trying to do the same thing. Using that knowledge you should be able to improve the regex in your patch as well.

Signed-off-by: Kapil Jain <jkapil.cs@gmail.com>
---

The test passes now, but imo the regex is not working, because the output of git diff with shell regex remains same as earlier it was without shell regex.

without shell regex the output was shown as: -$TEST_DIRECTORY +$TEST_DIR

with shell regex the output should be: [-$TEST_DIRECTORY-] {+$TEST_DIR+}

but even with shell regex the output is: -$TEST_DIRECTORY +$TEST_DIR

some thoughts on regex would be helpful. the shell regex is below:

+
+PATTERNS("shell",
+  /* Function Names */
+  "([A-Za-z_][A-Za-z0-9_]*)[[:space:]]*\\([[:space:]]*\\)[[:space:]]*\\{",
+  /* Words */
+  "([$#@A-Za-z_\"\'][$#@A-Za-z0-9_\"\']*)"),
+

Thanks.

 t/t4034/shell/expect | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)