Report paths consistently with watcher creation

lib/path-watcher.js

@@ -241,6 +241,18 @@ class PathWatcher {
       return true
     }
 
+    const shouldRewrite = !this.watchedPath.startsWith(this.normalizedPath)
+    const modifyPath = shouldRewrite
+      ? eventPath => this.watchedPath + eventPath.substring(this.normalizedPath.length)
+      : eventPath => eventPath
+    const modifyEvent = shouldRewrite
+      ? event => {
+        const e = {action: event.action, kind: event.kind, path: modifyPath(event.path)}
+        if (event.oldPath !== undefined) e.oldPath = modifyPath(event.oldPath)
+        return e
+      }
+      : event => event
+
     const filtered = []
     for (let i = 0; i < events.length; i++) {
       const event = events[i]
@@ -250,15 +262,15 @@ class PathWatcher {
         const destWatched = isWatchedPath(event.path)
 
         if (srcWatched && destWatched) {
-          filtered.push(event)
+          filtered.push(modifyEvent(event))
         } else if (srcWatched && !destWatched) {
-          filtered.push({action: 'deleted', kind: event.kind, path: event.oldPath})
+          filtered.push({action: 'deleted', kind: event.kind, path: modifyPath(event.oldPath)})
         } else if (!srcWatched && destWatched) {
-          filtered.push({action: 'created', kind: event.kind, path: event.path})
+          filtered.push({action: 'created', kind: event.kind, path: modifyPath(event.path)})
         }
       } else {
         if (isWatchedPath(event.path)) {
-          filtered.push(event)
+          filtered.push(modifyEvent(event))
         }
       }
     }

test/events/symlink.test.js

@@ -0,0 +1,44 @@
+const fs = require('fs-extra')
+
+const {Fixture} = require('../helper')
+const {EventMatcher} = require('../matcher')
+
+describe('watching beneath symlinked directories', function () {
+  let fixture
+
+  beforeEach(async function () {
+    fixture = new Fixture()
+    await fixture.before()
+    await fixture.log()
+  })
+
+  afterEach(async function () {
+    await fixture.after(this.currentTest)
+  })
+
+  it('reports paths consistently with the argument to watchPath', async function () {
+    const realSubdir = fixture.watchPath('realdir')
+    const realFile = fixture.watchPath('realdir', 'file.txt')
+
+    const symlinkSubdir = fixture.watchPath('linkdir')
+    const symlinkFile = fixture.watchPath('linkdir', 'file.txt')
+
+    await fs.mkdirs(realSubdir)
+    await fs.symlink(realSubdir, symlinkSubdir)
+
+    const symlinkMatcher = new EventMatcher(fixture)
+    const sw = await symlinkMatcher.watch(['linkdir'], {})
+
+    const realMatcher = new EventMatcher(fixture)
+    const rw = await realMatcher.watch(['realdir'], {})
+
+    assert.strictEqual(sw.native, rw.native)
+
+    await fs.writeFile(realFile, 'contents\n')
+
+    await Promise.all([
+      until('symlink event arrives', symlinkMatcher.allEvents({action: 'created', kind: 'file', path: symlinkFile})),
+      until('real path event arrives', realMatcher.allEvents({action: 'created', kind: 'file', path: realFile}))
+    ])
+  })
+})