Fix URLPath parsing other origins

CHANGELOG.md

@@ -5,6 +5,7 @@ This project adheres to semantic versioning.
 ## 0.19.0 (_Unreleased_)
 
 - Add `clone` to `URLPath`.
+- Fix `URLPath` incorrectly parsing alternative origins.
 - Fix typings in presence of `isolatedModules`.
 - Bump minimum supported Node LTS to v20.
 

src/URLPath.ts

@@ -179,7 +179,12 @@ export const fromString =
       // It should only throw some sort of `TypeError`:
       // https://developer.mozilla.org/en-US/docs/Web/API/URL/URL
       E.tryCatch(
-        () => new globalThis.URL(x, phonyBase),
+        () => {
+          const y = new globalThis.URL(x, phonyBase)
+          if (y.origin !== phonyBase)
+            throw new TypeError("Failed to retain phony base URL")
+          return y
+        },
         e => f(e as TypeError),
       ),
       E.map(pack<URLPath>),

test/URLPath.ts

@@ -159,6 +159,32 @@ describe("URLPath", () => {
 
       expect(e.name).toBe("TypeError")
     })
+
+    it("accepts all valid paths", () => {
+      fc.assert(
+        fc.property(fc.webPath(), x =>
+          expect(f(x)).toEqual(E.right(new URL(x, phonyBase))),
+        ),
+      )
+    })
+
+    it("does not parse origins", () => {
+      const g = fromString(identity)
+
+      const e1 = unsafeUnwrapLeft(g("//x"))
+      expect(e1.name).toBe("TypeError")
+      expect(e1.message).toMatch(/phony/)
+
+      const e2 = unsafeUnwrapLeft(g("https://samhh.com/foo"))
+      expect(e2.name).toBe("TypeError")
+      expect(e2.message).toMatch(/phony/)
+
+      fc.assert(
+        fc.property(fc.string().map(f).filter(E.isRight), ({ right: x }) =>
+          expect((x as unknown as URL).origin).toBe(phonyBase),
+        ),
+      )
+    })
   })
 
   describe("fromStringO", () => {