feat: read a file: URL the way Node does in absolutePath

.changeset/absolute-path-file-url.md

@@ -0,0 +1,5 @@
+---
+"schema-utils": minor
+---
+
+The `absolutePath` keyword reads a `file:` URL the way Node's own URL parser does: the scheme may be followed by any number of slashes, so `file:/directory` is accepted alongside `file:///directory`, and it is matched case-insensitively, so `FILE:///directory` is too. A scheme with no slash after it — `file:directory` — still names no absolute path and is rejected.

src/keywords/absolutePath.js

@@ -70,12 +70,15 @@ function addAbsolutePathKeyword(ajv) {
           passes = false;
         }
 
-        // (?:file:\/\/)? - optional file:// protocol prefix
+        // (?:file:(?=\/))? - optional file: scheme, which Node's URL parser
+        //   takes with any number of slashes after it, the lookahead leaving
+        //   the first one to the path itself
         // ?:[A-Za-z]:\\ - Windows absolute path
         // \\\\ - Windows network absolute path
         // \/ - Unix-like OS absolute path
         const isCorrectAbsolutePath =
-          schema === /^(?:file:\/\/)?(?:[A-Za-z]:(\\|\/)|\\\\|\/)/.test(data);
+          schema ===
+          /^(?:file:(?=\/))?(?:[A-Za-z]:(\\|\/)|\\\\|\/)/i.test(data);
 
         if (!isCorrectAbsolutePath) {
           callback.errors = [getErrorFor(schema, parentSchema, data)];

test/__snapshots__/index.test.js.snap

@@ -56,6 +56,16 @@ exports[`validation should fail validation for absolute path #4 1`] = `
  - configuration.testAbsolutePath: The provided value ".." is not an absolute path!"
 `;
 
+exports[`validation should fail validation for absolute path #5 1`] = `
+"Invalid configuration object. Object has been initialized using a configuration object that does not match the API schema.
+ - configuration.testAbsolutePath: The provided value "file:directory/deep/tree" is not an absolute path!"
+`;
+
+exports[`validation should fail validation for absolute path #6 1`] = `
+"Invalid configuration object. Object has been initialized using a configuration object that does not match the API schema.
+ - configuration.testAbsolutePath: The provided value "file:C:/directory/deep/tree" is not an absolute path!"
+`;
+
 exports[`validation should fail validation for absolute path 1`] = `
 "Invalid configuration object. Object has been initialized using a configuration object that does not match the API schema.
  - configuration.context: The provided value "baz" is not an absolute path!

test/index.test.js

@@ -333,6 +333,18 @@ describe("validation", () => {
     testAbsolutePath: "file:///C:/directory/deep/tree",
   });
 
+  createSuccessTestCase("absolutePath #8", {
+    testAbsolutePath: "file:/Users/username/directory/deep/tree",
+  });
+
+  createSuccessTestCase("absolutePath #9", {
+    testAbsolutePath: "file:/C:/directory/deep/tree",
+  });
+
+  createSuccessTestCase("absolutePath #10", {
+    testAbsolutePath: "FILE:///Users/username/directory/deep/tree",
+  });
+
   createSuccessTestCase("$data", {
     dollarData: {
       smaller: 5,
@@ -2982,6 +2994,22 @@ describe("validation", () => {
     (msg) => expect(msg).toMatchSnapshot(),
   );
 
+  createFailedTestCase(
+    "absolute path #5",
+    {
+      testAbsolutePath: "file:directory/deep/tree",
+    },
+    (msg) => expect(msg).toMatchSnapshot(),
+  );
+
+  createFailedTestCase(
+    "absolute path #6",
+    {
+      testAbsolutePath: "file:C:/directory/deep/tree",
+    },
+    (msg) => expect(msg).toMatchSnapshot(),
+  );
+
   createFailedTestCase(
     "not empty string #1",
     {
@@ -3109,6 +3137,8 @@ describe("validation", () => {
   // `import.meta.resolve()` returns a `file://` URL, so every option of webpack's own schema that
   // takes an absolute path has to accept one - these are all of them
   const WEBPACK_FILE_URL = "file:///directory/deep/tree";
+  // The same URL with the single slash Node's URL parser normalizes to three
+  const WEBPACK_SHORT_FILE_URL = "file:/directory/deep/tree";
 
   /** @type {Record<string, Record<string, EXPECTED_ANY>>} */
   const webpackAbsolutePathOptions = {
@@ -3205,6 +3235,17 @@ describe("validation", () => {
       {},
       webpackSchema,
     );
+
+    createSuccessTestCase(
+      `\`file:/\` for the webpack option \`${option}\``,
+      JSON.parse(
+        JSON.stringify(config)
+          .split(WEBPACK_FILE_URL)
+          .join(WEBPACK_SHORT_FILE_URL),
+      ),
+      {},
+      webpackSchema,
+    );
   }
 
   // The prefix must not turn an option that wants a relative path into an absolute one