• resolve() will append the query string for both exact and prefix mapping
• import statement query string will override the query string from import map
• lookup() will not consider any query string

Closes https://github.com/denoland/import_map/issues/46

@bartlomieju

When I went to go integrate this into Deno, I found that there was some extra complexity we were doing by converting back and forth between Url and str. It's easier to just use Url for the base here.

This PR adds an optional feature of graph which allows an import map to be used as a Resolver with deno_graph, and thereby be integrated into the CLI.

This commit adds handling of "npm:" specifiers in mapping. Specifically when mapping "packages" it prints out a diagnostics that the target must use "npm:/" instead of "npm:" (because the latter is not a valid base URL).

Needing to add dependency analysis for deno.land/x module documentation and need to be able to resolve specifiers with an import map, so exposing the import map crate as wasm makes sense instead of using something implemented just in JavaScript/TypeScript.

The lookup API was using the stored key, which when the there is a leading / it stores the key as relative to the base url. Previous versions incorrectly tried to strip just file:// from the key which breaks on windows. This now uses the raw_url of the value which should provide correct output in every scenario.

This adds a .lookup() API to an ImportMap. This effectively "reverses" a resolution, returning a import specifier string that would resolve to the same url specifier, but via the import map.

This is part of the journey of allowing the language server to offer quick fixes and auto import completions which identify to the user a situation where an import specifier can be remapped to an import map.

This will be used in deno vendor.

Adds:

• with_folder_removed(&self, folder: &Url) -> Self - Ability to remove a certain folder from the import map (will use this in deno vendor to remove the output directory)
• to_json() -> String - Gets the import map as JSON text.
• imports_mut().append(key, value)
• get_or_append_scope_mut(key)

In deno vendor if someone provides an import map in the vendor folder, then it should be ignored (ex. someone runs deno vendor then does deno vendor --import-map vendor/import_map.json). This will matter more once we have automatic deno.json import map resolution.

Although the base url could be stored along with the import map in deno's proc state, it's much easier to just add this method here.

As it turns out... it was way easier for me to just use the json feature in dnt. My bad! 🙈 I should refrain from opening PRs in other repos until I'm completely done implementing a feature (I have learned my lesson).

I also agree that there doesn't seem to be a good reason to not use the json method of doing things and so I've refactored this back.

We should add tests for the diagnostic scenarios because now it's easily testable. Not critical though and something for the future. Would be a good first issue for someone. Basically, just write more tests that check the diagnostic scenarios:

https://github.com/denoland/import_map/blob/c505b8397f8ce0c8b88db2a01c8fb8447ae6f717/src/lib.rs#L535-L540

Using import_map.json

{
  "imports": {
    "icons-solid-20/": "https://esm.sh/@heroicons/[email protected]/20/solid/?alias=react:preact/compat"
  }
}

With script:

import 'icons-solid-20/BeakerIcon';

Will yield error:

Import map diagnostics:
  - Invalid target address "https://esm.sh/@heroicons/[email protected]/20/solid/?alias=react:preact/compat" for package specifier "icons-solid-20/". Package address targets must end with "/".
error: Blocked by null entry for ""icons-solid-20/""

Even when putting in a bogus query parameter that ends with "/", the following error is produced:

error: The specifier ""icons-solid-20/BeakerIcon"" backtracks above its prefix ""icons-solid-20/""

Under Deno 1.23.3 and 1.24.0, it is possible to produce a panic when running deno check given a particular invalid import configuration.

See a minimal repro here.

Panic trace:

============================================================
Deno has panicked. This is a bug in Deno. Please report this
at https://github.com/denoland/deno/issues/new.
If you can reliably reproduce this panic, include the
reproduction steps and re-run with the RUST_BACKTRACE=1 env
var set and include the backtrace in your report.

Platform: macos aarch64
Version: 1.24.0
Args: ["/Users/henx/.deno/bin/deno", "check", "repro.ts"]

thread 'main' panicked at 'assertion failed: resolution_result.to_string().ends_with(\'/\')', /Users/ib/.cargo/registry/src/github.com-1ecc6299db9ec823/import_map-0.12.1/src/lib.rs:942:5
stack backtrace:
   0: _rust_begin_unwind
   1: core::panicking::panic_fmt
   2: core::panicking::panic
   3: import_map::resolve_imports_match
   4: import_map::ImportMap::resolve
   5: <deno::resolver::ImportMapResolver as deno_graph::source::Resolver>::resolve
   6: deno_graph::graph::resolve
   7: deno_graph::graph::parse_module_from_ast
   8: deno_graph::graph::parse_module
   9: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
  10: deno::proc_state::ProcState::prepare_module_load::{{closure}}
  11: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
  12: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
  13: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
  14: deno::main::{{closure}}
  15: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
  16: deno_runtime::tokio_util::run_local
  17: deno::main

Diagnostics for an import map should include locations/spans of errors in the source file, to make printing and using the diagnostics in language servers more useful.

@dsherret just added a strict parse mode to https://crates.io/crates/jsonc-parser, which can be used to parse and walk the JSON structure to improve the diagnostics. We should use that for parsing the import map and generating diagnostics.

Reproduce:

• Deno v1.23.3
• import_map.json:

{
  "imports": {
      "@mui/": "https://esm.sh/@mui/[email protected]/?alias=react:preact/compat,react/jsx-runtime:preact/compat/jsx-runtime&[email protected]"
  }
}

Deno then reports back with:

Package address targets must end with "/".

I couldn't find a current code snippet, but for version 1.9.1 I found this check, which doesn't account for esm.sh alias feature, because it just checks the last character of the value string.

If you have any further questions, please let me know

Discovered while looking into https://github.com/denoland/deno/issues/15266. The current import-map-relative design could pass as intentional, but that wasn't the way it was being used in cli and I think adjusting to the passed referrer makes more sense.

Also account for conflicts in lookup_imports(). Choose the least specific matching prefix key, rewrite the specifier with it, make sure the rewritten specifier isn't overrided by some other more specific prefix key. e.g.

// import_map.json
{
  "imports": {
    "a/": "https://foo.com/",
    "a/b/": "https://bar.com/"
  }
}

import_map.lookup("https://foo.com/b/c") should match the first entry, rewrite it to "a/b/c", realise that this conflicts with the second entry (it would be remapped to https://bar.com/c) and discard it.

• import_map enables serde_json/preserve_order
• serde_json/preserve_order depends on indexmap (https://docs.rs/crate/serde_json/latest/features)
• indexmap depends on hashbrown
• hashbrown depends on ahash by default.
• ahash depends on const-random

and the result is

❯ cargo check
    Updating crates.io index
error: cyclic package dependency: package `ahash v0.7.6` depends on itself. Cycle:
package `ahash v0.7.6`
    ... which satisfies dependency `ahash = "^0.7.0"` of package `hashbrown v0.11.2`
    ... which satisfies dependency `hashbrown = "^0.11"` of package `indexmap v1.8.0`
    ... which satisfies dependency `indexmap = "^1.5"` of package `serde_json v1.0.79`
    ... which satisfies dependency `serde_json = "^1.0"` of package `wasm-bindgen v0.2.79`
    ... which satisfies dependency `wasm-bindgen = "^0.2.79"` of package `js-sys v0.3.56`
    ... which satisfies dependency `js-sys = "^0.3"` of package `getrandom v0.2.3`
    ... which satisfies dependency `getrandom = "^0.2.0"` of package `const-random-macro v0.1.13`
    ... which satisfies dependency `const-random-macro = "^0.1.13"` of package `const-random v0.1.13`
    ... which satisfies dependency `const-random = "^0.1.12"` of package `ahash v0.7.6`