Unresolved import causes nls to panic

[mkatychev]

Describe the bug

[ERROR] .../vim/lsp/rpc.lua:789	"rpc"	"~/.nix-profile/bin/nls"	"stderr"	"thread 'main' panicked at core/src/typecheck/mod.rs:2819:26:Internal error: resolved import not found during typechecking.
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
"

To Reproduce
Declare an import in an ncl that has no resolution: let ObjectThatDoesNotExist = import "real_file.ncl in

Expected behavior
nls should be fault tolerant to an unresolved dependency tree and turn the panic below into an error or log for NLS:

nickel/core/src/typecheck/mod.rs

Lines 2817 to 2819 in c8e8401

	let t = r
	.get(*file_id)
	.expect("Internal error: resolved import not found during typechecking.");

Environment

• OS name + version: macOS 14.2.1 (23C71)
• Version of the code: 1.6.0

Additional context
neovim default LSP

[yannham]

Hi, thanks for the report. The issue isn't that the import isn't resolved (which is usually entirely fine for the LSP and the typechecker, if it can't be found), but rather that the import has been resolved at some point but the corresponding source isn't in the source cache anymore.

I wonder how that could have happened, as besides a few exceptions (temporary holders for error messages) we never remove stuff from the source cache; have you done anything special, like having a valid import that you deleted at some point while NLS was active?

I just tried your example, both with the error (you're missing a closing ") and without, and adding stuff to make it a proper program, but I can't trigger the bug - I just get a proper "import not found" error.

Would you have a minimal, complete and reproducible example that triggers the bug for you, to help us address the issue?

[mkatychev]

Hi @yannham I will try to produce an example

[yannham]

Hello @mkatychev, even without a small example, does this still happen on 1.7 ? We suspect #1944 might have solved the problem. Let us know!

[mkatychev]

Thanks for the followup @yannham let me get to it tomorrow. The issue was a bit hard to reproduce but that ticket looks like the right steps to make it happen since I was heavily refactoring imported modules

[mkatychev]

I'm not able to reproduce the issue w/ 1.7, thanks for the fix @jneem!