Nimsuggest crashes when run without a backend specified

[liquidev]

Happens on this file, I haven't been able to reproduce it on a smaller example but that shouldn't matter.

Since Nim 1.4 nimsuggest hits an assertion when run like this:

❯ nimsuggest tests/tchipmunk.nim
Hint: used config file '/home/daknus/.choosenim/toolchains/nim-1.4.0/config/nim.cfg' [Conf]
Hint: used config file '/home/daknus/.choosenim/toolchains/nim-1.4.0/config/config.nims' [Conf]
Hint: used config file '/home/daknus/.config/nim/nim.cfg' [Conf]
Hint: used config file '/home/daknus/.config/nim/config.nims' [Conf]
Hint: used config file '/home/daknus/Coding/Nim/rapid/tests/config.nims' [Conf]
fatal.nim(49)            sysFatal
Error: unhandled exception: extccomp.nim(631, 31) `false`  [AssertionDefect]

It doesn't crash however when the backend is specified explicitly:

❯ nimsuggest -b:c tests/tchipmunk.nim
Hint: used config file '/home/daknus/.choosenim/toolchains/nim-1.4.0/config/nim.cfg' [Conf]
Hint: used config file '/home/daknus/.choosenim/toolchains/nim-1.4.0/config/config.nims' [Conf]
Hint: used config file '/home/daknus/.config/nim/nim.cfg' [Conf]
Hint: used config file '/home/daknus/.config/nim/config.nims' [Conf]
Hint: used config file '/home/daknus/Coding/Nim/rapid/tests/config.nims' [Conf]
usage: sug|con|def|use|dus|chk|mod|highlight|outline|known|project file.nim[;dirtyfile.nim]:line:col
type 'quit' to quit
type 'debug' to toggle debug mode on/off
type 'terse' to toggle terse mode on/off
> 

And also doesn't crash on Nim 1.2.6.

My hunch is that the compiler itself initializes the backend to C by default, but not nimsuggest, hence the assertion is hit because the default backend is backendInvalid.

[timotheecour]

@liquid600pgm can you try right before this commit nim-lang/Nim#15549 as mentioned here:
nim-lang/Nim#15602 (comment)

[liquidev]

As per @Clyybber's suggestion on Discord, I cleared the nimcache and everything works correctly so far. I'll reopen if this ever turns up again.

[timotheecour]

having to clear the cache might be an acceptable-ish solution if using 2 different versions of nim, but not if using same version of nim and running some commands; is there a repro?

[liquidev]

I was able to reproduce this using the following steps:

# before running anything we're on 1.4.0, in rapid's root folder
choosenim 1.2.6
nim c tests/tchipmunk
choosenim 1.4.0
nimsuggest tests/tchipmunk.nim

[timotheecour]

thanks for the repro, I still think we should fix this

[liquidev]

Seems to still be present, and quite annoying :/ reopening.

It can just crash in the middle of editing the file (using nim.nvim) which then forces me to stop writing code, switch to my terminal, rm -rf ~/.cache/nim, and restart nimsuggest via a custom command. And it makes compile times slower because the cache is now gone.

[timotheecour]

can you try #117 (comment) ?