🐛 odd color-words colouring

[paulirish]

edit: I realized my original bug report on --word-diff is captured by the thread on #152

original report

I don't use word-diff very often, but it's occasionally useful. I noticed the color highlighting ain't great with delta. FWIW, this isn't high priority to me. :)

screenshots without and with delta:

(I've commented out all [color] and [delta] config for those)

In my case, using --max-line-distance with a few diff values didn't seem to change anything.

repro diff:

diff --git a/packs/joomla.js b/packs/joomla.js
index 2dd5c1c..4d29095 100644
--- a/packs/joomla.js
+++ b/packs/joomla.js
@@ -18 +18 @@ const UIStrings = {
  'offscreen-images': 'Install a [lazy-load Joomla plugin](https://extensions.joomla.org/instant-search/?jed_live%5Bquery%5D=lazy%20loading) that provides the ability to defer any offscreen images, or switch to a template that provides that functionality. Starting with Joomla 4.0, [-a dedicated lazy-loading plugin can be enabled by using-]{+all new images will [automatically](https://github.com/joomla/joomla-cms/pull/30748) get the `loading` attribute from+} the [-"Content - Lazy Loading Images" plugin. Also consider using [an AMP plugin](https://extensions.joomla.org/instant-search/?jed_live%5Bquery%5D=amp).',-]{+core.',+}

---

However, I'll change this bug report to be about --color-words.
It seems like delta handles some --color-words output well:

👍

but then other output gives it problems:

repro:

�[1mdiff --git a/packs/joomla.js b/packs/joomla.js�[m
�[1mindex 2dd5c1c..4d29095 100644�[m
�[1m--- a/packs/joomla.js�[m
�[1m+++ b/packs/joomla.js�[m
�[36m@@ -18 +18 @@�[m �[mconst UIStrings = {�[m
  'offscreen-images': 'Install a [lazy-load Joomla plugin](https://extensions.joomla.org/instant-search/?jed_live%5Bquery%5D=lazy%20loading) that provides the ability to defer any offscreen images, or switch to a template that provides that functionality. Starting with Joomla 4.0, �[31ma dedicated lazy-loading plugin can be enabled by using�[m�[32mall new images will [automatically](https://github.com/joomla/joomla-cms/pull/30748) get the `loading` attribute from�[m the �[31m"Content - Lazy Loading Images" plugin. Also consider using [an AMP plugin](https://extensions.joomla.org/instant-search/?jed_live%5Bquery%5D=amp).',�[m�[32mcore.',�[m

🤔

and here you asked if folks prefer delta's own highlighting...

Here's at least one case where delta's highlighting fails quite a bit (on --color-words output):

�[1mdiff --git a/packs/joomla.js b/packs/joomla.js�[m
�[1mindex 2dd5c1c..b18f833 100644�[m
�[1m--- a/packs/joomla.js�[m
�[1m+++ b/packs/joomla.js�[m
�[36m@@ -18 +18 @@�[m �[mconst UIStrings = {�[m
  'offscreen-images': �[31m'Install�[m�[32m'You can install�[m a [lazy-load Joomla plugin](https://extensions.joomla.org/instant-search/?jed_live%5Bquery%5D=lazy%20loading) that provides the ability to defer any offscreen images, or switch to a template that provides that functionality. Starting with Joomla 4.0, �[31ma dedicated lazy-loading plugin can be enabled by using�[m�[32mall new images will [automatically](https://github.com/joomla/joomla-cms/pull/30748) get the `loading` attribute from�[m the �[31m"Content - Lazy Loading Images" plugin. Also consider using [an AMP plugin](https://extensions.joomla.org/instant-search/?jed_live%5Bquery%5D=amp).',�[m�[32mcore.',�[m

i'm using 0.4.4.
cheers!

[dandavison]

Thanks @paulirish! I agree, both this and #152 would be good to fix soon.

[mrjoel]

I just ran into this issue with --color-words myself, except in this case I'd argue that it's broken since all formatting distinction is lost. I use --color-words in many of my git alias configurations so am finding myself running into this a lot. I ran into this first with diffing my .gitconfig in reviewing incorporation of delta, with ini style files seemingly very prone to getting confused.

Simplified reproducing test cases I encountered are below. I do have the style zero-style = dim syntax including in my settings, and noted that the faulty example resulted in syntax highlighting being included, although I don't know if that's related or not.

Working Example

Original:

foo = bar

Change working copy to:

foo = baz

Running git diff --color-words | delta works as expected, highlighting "bar" and "baz" with respective minus and plus styles.

Faulty Example

Original (same as above but with a single leading space):

 foo = bar

Change working copy to:

 foo = baz

Running git diff --color-words | delta does not work as expected, instead it strips all color formatting and stacks the words next to each other, simply showing foo = barbaz, apparently in zero-style.

[dandavison]

The current release (0.10.3) refuses to handle --word-diff or --color-words at all, instead allowing the raw git output through. I think this is at least a step in the right direction since what delta was doing previously to that input was entirely invalid. I believe that fixes (in a sense at least) both issues reported here. #152 discusses the possibility of delta introducing its own handing of these inputs, or its own "squashed diff" format (i.e. additions and deletions highlighted in a single line). Thanks for the bug reports here!

[mrjoel]

I just tested the new release and an initial testing am happy to confirm that the raw git formatting is preserved. That is indeed a marked improvement, thanks for taking this step!