[PATCH] search-paths: 'environment-variable-definition' output for fish

---

guix/search-paths.scm | 31 ++++++++++++++++++++++---------

1 file changed, 22 insertions(+), 9 deletions(-)

Hi Guix!

Some background on this patch:

Right now whenever I do any Guix operation that requires me to modify environment variables (e.g. installing a Guile library requires me to update

$GUILE_LOAD_PATH afterwards), Guix helpful tells me what commands I have to run to update the variables.

However, those commands are currently in bash/POSIX(?) format `export VAR=VALUE`. I've modified the `environment-variable-definition` function to

support the syntax for Fish shell as well. I don't know if this method of looking at the $SHELL variable is sound, but it works on my machine.

Documentation for the `set' function in Fish: https://fishshell.com/docs/current/commands.html#set

PS: this is my first non-package patch for Guix so I apologize if there is something wrong with the patch

Best regards,

-Dan

Hi,

Dan Frumin <dfrumin@cs.ru.nl> skribis:

But see https://issues.guix.gnu.org/issue/35942. :-)

“export VAR=VALUE” is actually Bash-specific. The POSIX way to do it

is:

VAR=VALUE; export VAR

Would that work with Fish?

If it does, we might just as well take that route as it will also cater

to other POSIX-compatible shells.

If not, your patch sounds like the right way.

Thanks,

Ludo’.

Hi Ludovic,

On 01-06-19 15:10, Ludovic Courtès wrote:

I was actually oblivious to the fact that these environment variables can be set up for you automatically in a new shell -- I guess that's because

both ~/.guix-profile/etc/profile and `guix package --search-paths` output everything in Bash format, so I didn't use it with Fish.

Unfortunately not. I wish they'd support more standard features.

Best,

Dan

Hi Dan,

Dan Frumin writes:

I think this patch will cause more trouble than good. Does this patch

replaces etc/profile with fish syntax script? etc/profile is supposed

to be in POSIX shell syntax. Fish shell has it's own configuration

files in /etc/fish/config.fish and /etc/fish/conf.d/*.fish. If you

really want to generate fish syntax scripts, please put them in

/etc/fish/config.fish or /etc/fish/conf.d/*.fish.

See:

1. https://lists.gnu.org/archive/html/guix-devel/2019-01/msg00071.html

2. https://lists.gnu.org/archive/html/guix-devel/2019-01/msg00333.html

3. https://issues.guix.gnu.org/issue/34153

Have you tried the fish-foreign-env package? You can source bash

scripts in fish via `fenv source ~/.guix-profile/etc/profile`. That's how

the fish shell in Guix set up environment variables upon login.

Perhaps we can handle this better. Do you have any suggestions? My

idea:

1. The fish-foreign-env package is very useful but it's not installed by

default in order to avoid polluting user's profiles according to the

Guix convention. In this case I think it's a useful utility rather than

pollution. Do you want it to be installed together with the fish

package by default?

2. etc/profile is supposed to be sourced by a login shell. And we

should avoid sourcing it from a non-login shell. That's why I made the

fish package in Guix only sources it upon login. That means starting a

new fish shell won't source it automatically. So please source it

manually if you need the new environment variables (fenv source

~/.guix-profile/etc/profile).

3. We can write better documentations explaining how to deal with fish

shell in Guix. There's an old discussion about having a Guix wiki or

a Guix book.

--

Meiyo Peng

Hi Meiyo,

On 03-06-19 07:51, Meiyo Peng wrote:

No, this patch doesn't touch etc/profile in any way, it is only concerned with the output that you get from `guix package` on your terminal.

So I guess it's kind of orthogonal to the upgraded fish package that you made?

Thanks! This is quite nice, I should upgrade my Fish installation.

Well, you added it as part of the fish dependency, right? I think it makes sense, especially on Guix SD.

I am not knowledgeable enough to comment on this, but it seems to me that it is done similarly if you are using bash: e.g. you have to source the

profile yourself if you want to get it in a non-login shell.

Yeah, more documentation is always better :)

Best regards,

-Dan

Hi Dan,

Dan Frumin writes:

Alright. Then that's fine. But there is an on going discussion about

change content of the message in bug #35942. I suggest we hold this

patch until that bug is closed.

Your fish shell is quite old. Older than Guix 1.0.0!

Yes, it's a dependency of fish. But it's not a propagated input. We

can change it into a propagated input if most users agree.

--

Meiyo Peng

Hi,

On 04-06-19 05:53, Meiyo Peng wrote:

Sure, makes sense to me.