Import maps don't work for mapping npm dependencies of npm packages

[oscarotero]

Version: Deno 1.42.4

I'm trying to replace a npm dependency using import maps, but suprisingly it doesn't seem to work.
Let's say I have this code:

// main.ts

import * as foo from "npm:micromatch@4.0.5";

If I run deno info main.ts I have the following dependency graph:

file:///Users/oscarotero/test/main.ts (44B)
└─┬ npm:/micromatch@4.0.5 (54.64KB)
  ├─┬ npm:/braces@3.0.2 (48.08KB)
  │ └─┬ npm:/fill-range@7.0.1 (15.97KB)
  │   └─┬ npm:/to-regex-range@5.0.1 (22.4KB)
  │     └── npm:/is-number@7.0.0 (9.39KB)
  └── npm:/picomatch@2.3.1 (87.84KB)

To replace braces@3.0.2 with another version, say braces@2.0.0, I add a new entry in the import map:

{
  "imports": {
    "npm:braces@3.0.2": "npm:braces@2.0.0",
  },
}

But after running deno info main.ts again, I see the same result without any change.
I tried different ways without luck:

{
  "imports": {
    "npm:braces@3.0.2": "npm:braces@2.0.0",
    "npm:braces@^3.0.2": "npm:braces@2.0.0",
    "braces": "npm:braces@2.0.0"
  },
  "scopes": {
    "npm:micromatch@4.0.5": {
      "npm:braces@^3.0.2": "npm:braces@2.0.0",
      "braces": "npm:braces@2.0.0"
    }
  }
}

I saw this issue #23310 and from I understand, I have to enable the unstable byonm feature. So I added it to my deno.json file:

{
  "unstable": ["byonm"],
  "imports": {
    "npm:braces@3.0.2": "npm:braces@2.0.0",
    "npm:braces@^3.0.2": "npm:braces@2.0.0",
    "braces": "npm:braces@2.0.0"
  },
  "scopes": {
    "npm:micromatch@4.0.5": {
      "npm:braces@^3.0.2": "npm:braces@2.0.0",
      "braces": "npm:braces@2.0.0"
    }
  }
}

Now I have the following error:

file:///Users/oscarotero/test/main.ts (44B)
└── Could not find a matching package for 'npm:micromatch@4.0.5' in '/Users/oscarotero/test/package.json'. You must specify this as a package.json dependency when the node_modules folder is not managed by Deno. (resolve error)

I don't understand what it means. Should I create a package.json file with this? Anyway, I did it:

{
  "dependencies": {
    "micromatch": "4.0.5"
  }
}

And now I have the following error:

file:///Users/oscarotero/test/main.ts (44B)
└── Could not find '/Users/oscarotero/test/node_modules/micromatch/package.json'. Deno expects the node_modules/ directory to be up to date. Did you forget to run `npm install`? (resolve error)

As far as I understand, I have to install the package with NPM? What's the point of that? Anyway, I run npm i and then deno info main.ts again, which returns the following error:

file:///Users/oscarotero/test/main.ts (44B)
├── file:///Users/oscarotero/test/node_modules/micromatch/index.js (unknown)
└── Failed resolving package subpath for 'npm:micromatch@4.0.5' in '/Users/oscarotero/test/node_modules/micromatch'. (resolve error)

And now I'm lost. Any idea how to make it work?

[dsherret]

This is tracked in #18191 (Import maps currently can't be used to change dependencies of npm packages, but yeah, byonm would be the way to do this atm)

I opened #23507 for the other issue you mentioned.