feat: check the files named by files, built by webpack or not

.changeset/files-outside-the-graph.md

@@ -0,0 +1,5 @@
+---
+"diagnostics-webpack-plugin": minor
+---
+
+Naming `files` now means every file they match is checked, whether or not webpack built it, for every check rather than only the ones that walk the file system by themselves. A module nothing imports yet was invisible to the ESLint check before. Left unset, a check still reads what it always read.

README.md

@@ -221,6 +221,12 @@ Specify directories, files, or globs. Must be relative to `options.context`.
 Directories are traversed recursively looking for files matching `options.extensions`.
 File and glob patterns ignore `options.extensions`.
 
+Naming them says what to check, so every file they match is checked whether or
+not webpack built it — a module nothing imports yet, or one reached through a
+loader webpack resolves differently, is checked all the same. Leave it unset and
+a check reads whatever it reads by itself: ESLint the modules webpack built,
+Stylelint a walk of the context.
+
 In a watch run the folder a check takes its files from is watched, so a file
 you add there is checked without anything else having to change — and for the
 `typescript` check, so is every folder the `tsconfig.json` `include` covers. A

src/index.js

@@ -32,6 +32,7 @@ import {
  * @property {CheckOptions} options options resolved for this check
  * @property {string[]} wanted the globs of the files to lint
  * @property {string[]} exclude the globs of the files not to lint
+ * @property {"modules" | "glob"} filesSource where the check's files come from
  * @property {(file: string) => boolean} isWanted whether a path is one to lint
  * @property {(file: string) => boolean} isExcluded whether a path is left out
  */
@@ -95,10 +96,10 @@ function contains(directory, path) {
  * @param {ResolvedCheck} check the check to answer for
  * @returns {string[]} the directories its globs are rooted at
  */
-function globRoots({ adapter, wanted }) {
+function globRoots({ filesSource, wanted }) {
   // A check reading the files webpack built has nothing to say about one
   // webpack does not build.
-  if (adapter.filesSource !== "glob") return [];
+  if (filesSource !== "glob") return [];
 
   /** @type {Set<string>} */
   const roots = new Set();
@@ -268,6 +269,9 @@ class DiagnosticsWebpackPlugin {
       name,
       adapter,
       options: resolved,
+      // A check told which files to check looks at all of them, whether or not
+      // webpack built them, whatever the check reads by itself.
+      filesSource: options.files ? "glob" : adapter.filesSource,
       wanted,
       exclude,
       // Compiled here rather than per call: the two run on every module of
@@ -342,7 +346,7 @@ class DiagnosticsWebpackPlugin {
       // Globbing the file system does not depend on the module graph, so a
       // child compilation would only lint what its parent already did.
       const enabled = compilation.compiler.isChild()
-        ? checks.filter(({ adapter }) => adapter.filesSource === "modules")
+        ? checks.filter((check) => check.filesSource === "modules")
         : checks;
 
       if (enabled.length === 0) return;
@@ -404,7 +408,7 @@ class DiagnosticsWebpackPlugin {
       });
 
       const fromModules = runners.filter(
-        ({ adapter }) => adapter.filesSource === "modules",
+        (check) => check.filesSource === "modules",
       );
 
       if (fromModules.length > 0) {
@@ -452,7 +456,7 @@ class DiagnosticsWebpackPlugin {
 
       // Nothing globbed from the file system waits on the module graph.
       for (const check of runners) {
-        if (check.adapter.filesSource === "modules") continue;
+        if (check.filesSource === "modules") continue;
 
         const collected = collectFromFileSystem(compiler, check);
 

src/shared-options.json

@@ -33,7 +33,7 @@
       ]
     },
     "files": {
-      "description": "Specify the files and/or directories to traverse. Must be relative to `options.context`.",
+      "description": "Specify directories, files, or globs to check. Naming them checks every file they match, whether or not webpack built it; left unset, a check reads whatever it reads by itself.",
       "anyOf": [
         {
           "type": "string"

test/fixtures/outside-entry.js

@@ -0,0 +1 @@
+require('./outside/good')

test/fixtures/outside/good.js

@@ -0,0 +1,3 @@
+const used = 1;
+
+module.exports = used;

test/fixtures/outside/orphan.js

@@ -0,0 +1 @@
+const neverImported = 1;

test/outside-graph.test.js

@@ -0,0 +1,54 @@
+import assert from "node:assert/strict";
+import { createRequire } from "node:module";
+import { join } from "node:path";
+import { describe, it } from "node:test";
+
+import pack from "./utils/pack.js";
+
+const require = createRequire(import.meta.url);
+
+describe("files outside the module graph", () => {
+  it("should check only what webpack built when no files are named", async () => {
+    const stats = await pack("outside").runAsync();
+
+    assert.strictEqual(stats.hasErrors(), false);
+    assert.strictEqual(stats.hasWarnings(), false);
+  });
+
+  it("should check a file webpack never built when files are named", async () => {
+    const stats = await pack("outside", { files: "outside" }).runAsync();
+
+    assert.strictEqual(stats.hasErrors(), true);
+
+    const [{ message }] = stats.compilation.errors;
+
+    assert.match(message, /orphan\.js/u);
+    assert.match(message, /no-unused-vars/u);
+  });
+
+  it("should watch the folder it was told to check", async () => {
+    const stats = await pack("outside", { files: "outside" }).runAsync();
+    const watched = [...stats.compilation.contextDependencies];
+
+    // A check reading the module graph has nothing to say about a file that
+    // is not in it; one told where to look is watched there like any other.
+    assert.ok(
+      watched.includes(join(import.meta.dirname, "fixtures", "outside")),
+    );
+  });
+
+  it("should still check what webpack built when files are named", async () => {
+    const eslintPath = join(import.meta.dirname, "mock/eslint-recorder");
+
+    require(eslintPath)._reset();
+
+    // The walk covers the imported file as well as the orphan, rather than
+    // replacing the graph with whatever the graph left out.
+    await pack("outside", { eslintPath, files: "outside" }).runAsync();
+
+    const linted = require(eslintPath)._calls.flat().join();
+
+    assert.match(linted, /outside\/good\.js/u);
+    assert.match(linted, /outside\/orphan\.js/u);
+  });
+});

types/index.d.ts

@@ -30,6 +30,10 @@ export type ResolvedCheck = {
    * the globs of the files not to lint
    */
   exclude: string[];
+  /**
+   * where the check's files come from
+   */
+  filesSource: "modules" | "glob";
   /**
    * whether a path is one to lint
    */