Fix unbound variable error in install script

[brettdh]

If the docker-compose version was less than the minimum required version, the install script would error out like this:

❯ ./install.sh
<snip>
▶ Checking minimum requirements ...
Found Docker version 27.5.1
install/check-minimum-requirements.sh: line 17: install: unbound variable

With this patch, the script correctly identifies the out-of-date docker-compose version and bails out with a more helpful message:

❯ ./install.sh
<snip>
▶ Checking minimum requirements ...
Found Docker version 27.5.1
FAIL: Expected minimum docker compose version to be 2.132.2 but found 2.32.4-desktop.1

(Note that 2.132.2 is not a real docker-compose version; I've edited the install/_min-requirements.sh file locally for testing, to make the installed version out of date.)

Also tested that the success case still works (by removing the aforementioned local edit):

❯ ./install.sh
<snip>
▶ Checking minimum requirements ...
Found Docker version 27.5.1
Found Docker Compose version 2.32.4-desktop.1

Legal Boilerplate

Look, I get it. The entity doing business as "Sentry" was incorporated in the State of Delaware in 2015 as Functional Software, Inc. and is gonna need some rights from me in order to utilize my contributions in this here PR. So here's the deal: I retain all rights, title and interest in and to my contributions, and by keeping this boilerplate intact I confirm that Sentry can use, modify, copy, and redistribute my contributions, under Sentry's choice of terms.

[aminvakil]

I think the problem relies somewhere else, why COMPOSE_VERSION should not be set and therefore inbound variable, maybe it's related to #3595 ?

@brettdh Can you please paste output of these two commands?

docker-compose version
docker compose version

[BYK]

Not sure why or how this happens but should be solved with #3604.

[brettdh]

@aminvakil

❯ docker-compose version
Docker Compose version v2.32.4-desktop.1

❯ docker compose version
Docker Compose version v2.32.4-desktop.1

[brettdh]

I figured out the root cause by adding | tee ./vergte.out to the $(vergte ...) invocation in the script and line named in the error output. Here's the content:

❯ cat vergte.out
Error in install/_lib.sh:57.
'sort --version-sort --check=quiet --reverse' exited with status 1
-> ./install.sh:main:20
--> install/check-minimum-requirements.sh:source:17
---> install/_lib.sh:vergte:57

Cleaning up...
1

Because cleanup() in install/error-handling.sh prints to stdout rather than stderr, this output gets printed as part of vergte, then the caller captures it and treats part of it as a variable named install, which is unbound, hence the error.

Changing vergte to just rely on its own exit code rather than forwarding the exit code of sort via stdout resolves this. Changing cleanup() to print to stderr would also likely resolve it, but I don't see a reason that vergte needs to use stdout when the exit code is all that matters.

[aminvakil]

There was a PR changing vergte function, so that it would not rely on return code, but I cannot find and don't remember why it wasn't merged, maybe I was dreaming someone had changed it ? :)

[BYK]

Okay, if tests etc pass I think I'm convinced that this is a better approach.

Huge props to @brettdh for the detective work and the patience to explain it to us!

[brettdh]

Fixed the formatting violations that pre-commit flagged.

[hubertdeng123]

Other than that, this change seems reasonable

[brettdh]

I think I'm fighting with vscode auto save behavior on the formatting issues. Sorry for the noise; will actually set up pre-commit and fix it that way soon.

[brettdh]

Ok it should be good now, including formatting and conflict resolution with recent changes on master.