Building problems: "build failed" error

[temhelk]

I'm trying to build llpp myself and I'm getting "build failed" error when I run bash ./build.bash build. I tried to debug that issue and that's what I found. I'm sorry if I got something wrong, not a bash person.

The scripts exits after a call to this function defined like that:

isfresh() { test "$(<$1.past)" = "$2"; } 2>/dev/null

https://github.com/criticic/llpp/blob/63def6568f1dca6a49f9f870164a5f726e6d59fe/build.bash#L198

If I understand correctly it makes the script exit because it tries to read the content of the file "$1.past" that doesn't exist when you build it the first time.

After changing the function to that:

isfresh() {
    test -f "$1.past" || return 1
    test "$(<$1.past)" = "$2"
} 2>/dev/null

It seems to work and build the application on the first run and skips everything on the second. Is that a problem with my environment or what is going on?

[fstecker]

I would guess that it's something about your environment. What operating system are you on, and which version of bash are you using? Also, can you share the output of echo "$-" to see which shell options are active?

As a simplified test case, if you run something like

test "<(nonexistent)" = "x" || echo y

what does it do? I just get the output "y" without an error.

[txtsd]

This happens when building from the AUR. I submitted a patch to the llpp AUR package that makes it build, and I'm providing the same fix here upstream with #10.

[fstecker]

I updated my Arch Linux and now get the same problem. The update included a new version of bash, so maybe that's actually what changed.

In any case, I think we should fix this here instead of adding a patch to the AUR package.

[txtsd]

Oh I didn't realise you were stek on the AUR 😅. It's much easier to fix it here in that case.

[fstecker]

I'm excited to see I'm not the only one still using this program! That gives me hope we can keep it maintained without the original developer.

I propose we wait for a bit if anyone else has some thoughts on this, but if not I'll just merge your fix.

[fstecker]

I did some additional tests and it turns out that indeed the behavior of bash changed. Something like

set -e
echo "$(<nonexistent)"

used to just generate an error message in bash 5.1 and leave the shell running, but in version 5.2 it closes the shell.

Anyway, thank you @temhelk and @txtsd for fixing it!