Issue: depcruise doesn't fail if the path patterns in `from` or `to` are never matched

[JavaScriptBach]

Expected Behavior

If I write a reachability rule, and the paths defined in from or to don't resolve to actual files on disk, I've written an incorrect rule. It would be best if depcruise failed in this case so that the developer can catch and fix the rule. It also helps ensure that dependency tests continue to stay in sync as files are moved around.

Current Behavior

depcruise silently succeeds.

Possible Solution

Make depcruise fail if from or to are never matched by a file on disk.

Steps to Reproduce (for bugs)

I'm using 16.9.0-beta-1 and able to reproduce this with a simple rule of the form of

{
      from: {
        path: "path/that/doesnt/exist.ts",
      },
      to: {
        path: "path/that/exists.ts",
        reachable: true,
      },
    },

Context

I'm writing rules in depcruise, putting them in my CI, and I want them to continue to stay correct over time.

Your Environment

• Version used: 16.9.0-beta-1
• Node version: 20
• Operating System and version: Ubuntu 22

[sverweij]

Hi @JavaScriptBach that's a good suggestion. Making dependency-cruiser fail might be a bit harsh (it'll be a breaking change - and there might be legitimate reasons to have something not match e.g. in the to parts of rules), but warning/ info messages should be just as useful.

I'll see if I can whip up something.

[JavaScriptBach]

Thank you for your consideration! Out of curiosity, what is a legitimate reason to have to not match a file? I couldn't think of one because 1) I'd expect all imports to be resolvable to files, and 2) if either from or to never match, the rule is effectively a no-op.

[sverweij]

Out of curiosity, what is a legitimate reason to have to not match a file?

E.g. when the to isn't (and perhaps, depending on the rule) shouldn't be part of the dependency-graph altogether. Two examples:

// .dependency-cruiser.mjs
export default {
  forbidden: [
    {
      name: "no-deprecated-core",
      from: {},
      to: {
        dependencyTypes: ["core"],
        path: [
          "^v8/tools/codemap$",
          "^v8/tools/consarray$",
          "^v8/tools/csvparser$",
         // ...
       ]
      }
    },
    {
      name: "not-to-dist",
      from: {
        path: "^src/",
      },
      to: {
        path: "^dist/",
      }
    },
  ]
}