Git development
 help / color / mirror / Atom feed
* pager: consider revisiting automatic LESS=FRX with custom core.pager
@ 2026-09-19 12:19 Francisco Boni
  2026-09-19 15:48 ` brian m. carlson
  0 siblings, 1 reply; 7+ messages in thread
From: Francisco Boni @ 2026-09-19 12:19 UTC (permalink / raw)
  To: git

Hi,

I ran into a surprising interaction between Git's pager environment
handling and a custom pager, and I think the longstanding automatic
`LESS=FRX` behavior may be worth revisiting.

My setup is roughly:

```
[core]
    pager = delta
```

with delta eventually invoking `less`.

In my shell I had:

```
export PAGER="less"
```

but deliberately did not set `LESS`.

I also configured delta's pager explicitly as:

```
less --RAW-CONTROL-CHARS --quit-if-one-screen --quit-on-intr --ignore-case
```

What surprised me was that:

```
git diff <commit1> <commit2>
```

caused the downstream `less` process to behave as though `-X` /
`--no-init` had been specified: it did not use the alternate screen,
and in my terminal Page Up / Page Down also stopped behaving normally.

The `less` argv itself looked as expected and did not contain `-X`.

Eventually I tracked this down to Git setting:

```
LESS=FRX
```

when `LESS` is absent from the environment.

The particularly revealing test was:

```
LESS="" git diff <commit1> <commit2>
```

With that single change, the same delta -> less chain used the
alternate screen normally and Page Up / Page Down worked again.

I understand that Git's default `LESS=FRX` behavior is old,
documented, and presumably exists to provide useful defaults when Git
directly invokes `less`.

What seems questionable to me is that it is also applied when
`core.pager` is an arbitrary custom command.

In this case the effective chain is:

```
git -> delta -> less
```

Git is not invoking `less` itself, but the `LESS=FRX` value injected
by Git is inherited by delta and then by the `less` process launched
by delta.
As a result, Git ends up silently configuring an implementation detail
of a pager wrapper. A user who explicitly configures:

```
core.pager = delta
```

would not necessarily expect Git to alter environment variables
specific to another pager that delta may or may not use internally.

There is also an unintuitive distinction between:

```
unset LESS
```

and:

```
LESS=""
```

The former causes Git to inject `FRX`, while the latter causes Git to
leave the pager environment alone.

I realize simply removing the default could have substantial
compatibility consequences given how longstanding this behavior is.
But perhaps it would be worth considering whether the automatic `LESS`
default should:

* apply only to Git's own default pager path;
* be suppressible explicitly through configuration; or
* otherwise avoid affecting arbitrary custom `core.pager` commands.

For my own setup, explicitly setting:

```
export LESS="--RAW-CONTROL-CHARS --quit-if-one-screen --quit-on-intr
--ignore-case"
```

solves the issue cleanly, because Git then leaves `LESS` untouched.

So this is not primarily a request for a workaround; rather, I wanted
to raise the broader behavior because the interaction with pager
wrappers is quite surprising and difficult to diagnose.

Thanks,
Francisco Boni

^ permalink raw reply	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2026-10-06 16:01 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2026-09-19 12:19 pager: consider revisiting automatic LESS=FRX with custom core.pager Francisco Boni
2026-09-19 15:48 ` brian m. carlson
2026-09-19 16:37   ` Todd Zullinger
2026-10-02 23:41     ` [PATCH] doc: add more examples of overriding LESS in core.pager Todd Zullinger
2026-10-05 23:59       ` brian m. carlson
2026-10-06 16:01         ` Junio C Hamano
2026-09-19 16:52   ` pager: consider revisiting automatic LESS=FRX with custom core.pager Francisco Boni

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox