From: Francisco Boni <boboniboni@gmail.com>
Date: Sat, 19 Sep 2026 12:19:40 GMT
Subject: pager: consider revisiting automatic LESS=FRX with custom core.pager
Message-ID: <CAKNeS+mFS_VCs_tQeFb8jBx70FwQLW0LtuqhSk4xSdbWdqDR=g@mail.gmail.com>

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