🐛 git add -p one-to-one correspondence errors

[Minnozz]

When I try to use git add -p, I get the following error:

$ git add -p
fatal: mismatched output from interactive.diffFilter
hint: Your filter must maintain a one-to-one correspondence
hint: between its input and output lines.

I'm using delta with the following config:

$ delta --version
delta 0.4.3
$ delta --show-config
    commit-style                  = raw
    file-style                    = blue
    hunk-header-style             = syntax
    minus-style                   = syntax 52
    minus-non-emph-style          = syntax 52
    minus-emph-style              = syntax 88
    minus-empty-line-marker-style = normal 88
    zero-style                    = syntax
    plus-style                    = syntax black
    plus-non-emph-style           = syntax black
    plus-emph-style               = syntax 22
    plus-empty-line-marker-style  = normal 22
    whitespace-error-style        = reverse magenta
    24-bit-color                  = false
    file-added-label              = 'added:'
    file-modified-label           = ''
    file-removed-label            = 'removed:'
    file-renamed-label            = 'renamed:'
    hyperlinks                    = false
    inspect-raw-lines             = true
    keep-plus-minus-markers       = true
    line-numbers                  = true
    line-numbers-minus-style      = red
    line-numbers-zero-style       = brightgreen
    line-numbers-plus-style       = green
    line-numbers-left-style       = blue
    line-numbers-right-style      = blue
    line-numbers-left-format      = '{nm:^4}⋮'
    line-numbers-right-format     = '{np:^4}│'
    max-line-distance             = 0.6
    max-line-length               = 512
    navigate                      = false
    paging                        = auto
    side-by-side                  = false
    syntax-theme                  = Solarized (dark)
    width                         = 145
    tabs                          = 4
    word-diff-regex               = '\w+'

In my .gitconfig are the following relevant options:

[core]
        pager = delta
[delta]
        commit-style = raw
        file-style = blue
        hunk-header-style = syntax
        minus-style = syntax 52
        minus-emph-style = syntax 88
        zero-style = syntax normal
        plus-style = syntax black
        plus-emph-style = syntax 22
        keep-plus-minus-markers = true
        line-numbers = true
        line-numbers-minus-style = red
        line-numbers-zero-style = brightgreen
        line-numbers-plus-style = green
        whitespace-error-style = reverse magenta
        minus-empty-line-marker-style = normal 88
        plus-empty-line-marker-style = normal 22
[interactive]
        diffFilter = delta --color-only
[color]
        ui = true

[dandavison]

Hi @Minnozz, thanks for this, very helpful. Clearly the test suite needs to be strengthened for git add -p also. I know git add -p is important, so this is probably the top priority for delta bugs right now.

[Minnozz]

Hi @dandavison, let me know if you need more information.

I looked for causes of this bug before, and

side-by-side = true
hunk-header-style = omit (only omit. I usually use this option except when git add -p)
file-style = (any option interestingly)

these options made it happened.
@Minnozz 's config can work if you remove file-style one.

[Kr1ss-XD]

I'd like to note that git add -p works here although I'm using file-style. Maybe it does not play well in combination with some other option(s) ?

For reference, my delta --show-config.

EDIT Oddly enough this config doesn't break add -p either in my environment. It contains all of the options mentioned above by @Ryuta69.

Thank you @Kr1ss-XD for looking. Hmm, I tried same config with you, however, it doesn't work. (core.pager = delta, and interactive.diffFilter = delta --color-only)

As picture showing,

❯ git --version
git version 2.28.0 (latest)
❯ delta --version
delta 0.4.3 (latest)

OS is MacOS Catalina 10.15.6.

Additionally, with your config, if I delete

file-style                    = bold 232 bright-yellow
hunk-header-style             = omit normal
side-by-side                  = true

now it works.

[Kr1ss-XD]

That's weird.

I'm trying @Minnozz 's configuration as I'm writing. It seems if the file option is deleted, it actually works, just as you suggested.

FWIW,

$ git --version; delta --version; uname -smro
git version 2.28.0
delta 0.4.3
Linux 5.7.19-1-ck x86_64 GNU/Linux

I hope this helps chasing that bug.

[Kr1ss-XD]

I think I found something :

If I put the file-style option in a feature category, git add -p works with the @Minnozz configuration !

[delta]
    features = files
    <... other options ...>
[delta "files"]
    file-style = blue

cc @dandavison

EDIT The same applies to hunk-header-style = omit.

@Kr1ss-XD
Oh!
Same as hunk-header-style, and side-by-side. Moving them to features, git add -p works while usual git diff work as those options enabled!

I think

src/options/set.rs
    if config::user_supplied_option("color-only", arg_matches) {
        builtin_features.remove("side-by-side");
    }

this is the reason why side-by-side works. I look for file-style, hunk-header-style's reasons.

[dandavison]

Thanks a lot @Kr1ss-XD and @Ryuta69 for investigating here.

I think @Kr1ss-XD's suggestion of using features to work around these issues is an excellent one for now, until we fix all the git app -p bugs.

@Kr1ss-XD I'm finding that I have to move both the file-style and hunk-header-style to a feature to make @Minnozz's config work under git add -p.

So, to be completely explicit, here is a modification of @Minnozz's config that I am finding works.

[delta]
    features = meta
    commit-style = raw
    # file-style = blue
    # hunk-header-style = syntax
    minus-style = syntax 52
    minus-emph-style = syntax 88
    zero-style = syntax normal
    plus-style = syntax black
    plus-emph-style = syntax 22
    keep-plus-minus-markers = true
    line-numbers = true
    line-numbers-minus-style = red
    line-numbers-zero-style = brightgreen
    line-numbers-plus-style = green
    whitespace-error-style = reverse magenta
    minus-empty-line-marker-style = normal 88
    plus-empty-line-marker-style = normal 22

[delta "meta"]
    file-style = blue
    hunk-header-style = syntax

[delta "diff-filter"]
    # Can leave empty, but optionally put diffFilter-only settings here

[interactive]
    # I've added a --features override here to be explicit that we don't want diffFilter to use the
    # features defined in the main [delta] section.
    diffFilter = delta --color-only --features=diff-filter

[dandavison]

I look for file-style, hunk-header-style's reasons.

@Ryuta69 It would be awesome if you can make progress here! I'm not certain but I think
#272 (comment) may be relevant.

[WIP]

commit_style = omit
hunk-header-decoration-style = {any option}

also triggers this bug. (It's because it removes commit hash.)

I build test, then I realized only commit-style=omit, file-style={any except raw}, and hunk-header-style={any except raw} cause this bug.

It's still WIP, but gonna send PR in few days.