Regression when using relative import map in deno.json

[NeKzor]

Version: Deno 1.41.3

A single ../ in the path value for "importMap" inside deno.json config file will output error: Loading unprepared module when using deno run.

Minimal reproducible example:

$ cat main.ts
import '~/shared/models.ts';

$ cat deno.json 
{
  "importMap": "../import_map.json"
}

$ cat ../import_map.json 
{
    "imports": {
        "~/shared/": "./shared/"
    }
}

$ cat ../shared/models.ts 
export class Model {}

This happens since 1.41.1 but I decided to build Deno from source to find the exact commit that caused this: 6567dc9

Running the debug build will trigger a panic at this location:

deno/cli/args/import_map.rs

Lines 77 to 81 in ae52b49

	debug_assert!(
	!specifier.as_str().contains("../"),
	"Import map specifier incorrectly contained ../: {}",
	specifier.as_str()
	);

The current workaround is to use "imports" in the config file or to use the --import-map flag.

[k-paxian]

Thank you so much @NeKzor for workaround 🎉 ❤️
It saved me literally hours 🍺

[dsherret]

Fixed a couple weeks ago in #23602