git log | bat looks nice, but PAGER=bat git log looks bland

[davidmaxwaterman]

(Sorry, I'm new to bat and OSX)

If I do git log | bat, I get nice colours, notably 'commit', 'Author', and 'Date' are in red, hash is purple, comment in orange. eg:

However, if I do git -c core.pager=bat log, it only has very limited colours...commit and the hash itself at yellow, the branch name (eg HEAD ->) are cyan, and any local branch name is green; but more importantly, the rest of the commit is some kind of ugly grey colour:

I just noticed that $ git config -l --global also uses bat, but the colour highlighting is all 'bland'

Any ideas what's going on?

 $ bat --version                                                                                            
bat 0.22.1
$ brew info bat                                                                                            
==> bat: stable 0.22.1 (bottled), HEAD
Clone of cat(1) with syntax highlighting and Git integration
https://github.com/sharkdp/bat
/opt/homebrew/Cellar/bat/0.22.1 (14 files, 4.7MB) *
  Poured from bottle on 2022-09-29 at 11:20:43
From: https://github.com/Homebrew/homebrew-core/blob/HEAD/Formula/bat.rb
License: Apache-2.0 or MIT
==> Dependencies
Build: rust ✘
==> Options
--HEAD
	Install HEAD version
==> Caveats
zsh completions have been installed to:
  /opt/homebrew/share/zsh/site-functions
==> Analytics
install: 44,926 (30 days), 68,454 (90 days), 220,976 (365 days)
install-on-request: 44,576 (30 days), 67,829 (90 days), 219,032 (365 days)
build-error: 0 (30 days)
$ git --version                                                                                            
git version 2.35.1
$ printenv | grep PAGER                                                                                    
PAGER=bat

[keith-hall]

You can try telling bat the language to highlight with explicitly, i.e. git -c core.pager="bat -l'Git Log'" log

[davidmaxwaterman]

Thanks for responding.

That is interesting...it does change things, but it is a sort of 'in between'.
It seems to change the colours of the first commit's 'header lines', and even the first line of the comment 'Bug .... - ...', plus it seems to highlight bug numbers and things that I presume it thinks are bug numbers.

Below are a few larger screenshots of the same log.

I notice that the actual text is different. When using a pipe, the log is simpler (doesn't output the branches/tags). I've seen that before - due to the git log --decorate=auto default changing when the output is a terminal vs a pipe. Specifying a decorate of short or full changes things yet again. Could it simply be poor syntax pattern matching? If I specify decorate of 'no' for both...(trying it out)...well, I was hoping that would at least make them the same, but it doesn't - the text is the same though, so I think we can rule out that being the issue :/

FWIW, the command I'll test with from now on will specify --decorate, eg:

git log --decorate=no | bat
git -c core.pager=bat log --decorate=no

(to be clear, the screenshots don't specify, and specifying the language still does the 'in between' highlighting show below)

Note that the highlighting of the word 'error' is done by iTerm2, not bat - and turning that off makes no difference to the problem.

With git -c core.pager="bat -l'Git Log'" log:

and with git log | bat:

and here is the same with git -c core.pager="bat" log:

[keith-hall]

I think that this bug is related: #1632
I have made a fix upstream, but I think bat is stuck on an old version until the syntax highlighting library we use is updated to support more recent features: trishume/syntect#323

[davidmaxwaterman]

OK. Yes, it does look related, though not precisely the same.

TBH, I'm struggling to make bat 'look good' in many scenarios. Even man git-log was difficult to read (PAGER=bat) - or perhaps that's more a matter of the default theme and I should just pick another one? Using TwoDark is readable, but bland/monochrome (with some seemingly random highlighting). Any recommendation?

[davidmaxwaterman]

You know, thinking about it, I don't see how it can be due to that bug you mention. If I do git log | bat, it looks fine...with the same input...so how can it be?

Somehow, when run through a config (eg with PAGER=bat or core.pager=bat) it doesn't look good; but with it as a filter ie | bat it does look good.

So, it seems like it is doing something different between those two cases.

[davidmaxwaterman]

OK, I found something.

If I use the following git command then it works the same with either PAGER=bat or | bat:

git log --no-color --no-decorate

However, --no-decorate means the output isn't as useful (due to no branch/tags/etc).

If I use PAGER="tee ~/tmp.txt" and look at the raw output, I see:

The --no-decorate produces a commit line like this:

�^[[33mcommit f4f084dd1ed256101665becb21828ef8d594e399�^[[m

and the --no-color produces:

commit f4f084dd1ed256101665becb21828ef8d594e399 (HEAD -> esr102, origin/branches/default/5909e8822d62ab7f80d6667e448742396715f207, origin/bookmarks/esr102)

So, the escape sequences in the --no-decorate output is messing bat up, and
the decoration text in the --no-color output is messing bat up.

The only way to get good output for both PAGER and pipe, is to use both --no-decorate and --no-color.

So, it is some additional differences in the output of git log between sending output to terminal and sending into a pipe, that are causing this issue?

[cben]

IIUC git's default is --color=auto so redirecting stdout e.g. git log | bat implies --no-color as git can't know who'll be reading.
OTOH a pager (whether set by core.pager config, or GIT_PAGER env var) is expected to support color (like less -R).

I see how having both git & bat colorize will collide, unpredictably.
But for me GIT_PAGER="bat -l'gitlog'" git log --no-color --decorate works fine, as of bat 0.25.0.

Though it's not as good as git's own colorization, e.g. git also colors decorations, and --graph lines, and honors %C color specs in custom --pretty formats... Git really knows what it's printing while bat has to reverse-engineer it.

Are you sure you want bat to parse & colorize git output?
One area where bat could win is syntax highlighting any source code that's printed but it's tricky to configure, and the central use case of git diff (and git log --patch) is covered by https://github.com/dandavison/delta/ (which uses same highlighting as bat +-backgrounds 🌈)

[drskoolie]

Having bat as my pager messes up my other aliases, so I put this in my .gitconfig:

`
[alias]

lo = "! f() { git log --no-color --no-decorate | bat -n -l 'Git log' ; }; f"

`

And it is run by typing in git lo