fix(createTokens): follow a {alias} reached through a segment path (#589)

* fix(createTokens): follow a {alias} reached through a segment path

The segment-path branch of resolve() assigned a terminal value to the
result without following a trailing {alias}, so a dotted-segment lookup
landing on an alias string returned the raw '{alias}' instead of its
resolved value. The leaf-value branch already re-resolved terminal
aliases; the segment branch now mirrors it, reusing the visited set so
circular detection still holds.

Surfaces through useTheme, which resolves theme colors through a
flat: true token table: a palette entry that is itself an alias,
referenced by a theme via a dotted alias, previously produced an
unresolved {alias} (dropped by the CSS brace guard, or leaked literally
to consumers reading theme.colors directly).

Ref #566 (Group A, item #1)

* test(createTokens): guard segment-path terminal alias resolution

Regression tests for the #566 fix: a {alias} reached through a dotted
segment lookup must be followed (single hop and multi-hop chain), and a
circular reference reached that way must be detected rather than leaking
a raw {alias}. All three fail against the pre-fix segment branch.

Author: johnleider

.changeset/tokens-segment-alias-followthrough.md

@@ -0,0 +1,7 @@
+---
+"@vuetify/v0": patch
+---
+
+fix(createTokens): follow a `{alias}` reached through a segment path (#566)
+
+`resolve()` now re-resolves an alias that a dotted-segment lookup lands on, instead of returning the raw `'{alias}'` string. This is visible under `flat: true` (where nested groups are stored whole and addressed by segment), so `useTheme` — which resolves theme colors through a `flat: true` token table — no longer drops or leaks an unresolved `{alias}` for a palette entry that is itself an alias. The leaf-value branch already followed terminal aliases; the segment branch now matches it.

packages/0/src/composables/createTokens/index.test.ts

@@ -1259,6 +1259,37 @@ describe('createTokens', () => {
       })
     })
 
+    describe('segment-path terminal alias (#566)', () => {
+      it('should follow a {alias} reached through a segment path', () => {
+        const context = createTokens({
+          colors: { primary: '#00f' },
+          group: { blue: '{colors.primary}' },
+        }, { flat: true })
+
+        expect(context.resolve('{group.blue}')).toBe('#00f')
+      })
+
+      it('should follow a multi-hop chain reached through a segment path', () => {
+        const context = createTokens({
+          colors: { base: '#0f0', primary: '{colors.base}' },
+          group: { blue: '{colors.primary}' },
+        }, { flat: true })
+
+        expect(context.resolve('{group.blue}')).toBe('#0f0')
+      })
+
+      it('should detect a circular reference reached through a segment path', () => {
+        const context = createTokens({
+          a: { x: '{b.y}' },
+          b: { y: '{a.x}' },
+        }, { flat: true })
+        using warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {})
+
+        expect(context.resolve('{a.x}')).toBeUndefined()
+        expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining('Circular alias detected'))
+      })
+    })
+
     describe('cache behavior', () => {
       it('should cache resolved values', () => {
         const tokens: TokenCollection = {

packages/0/src/composables/createTokens/index.ts

@@ -248,6 +248,8 @@ export function createTokens<
         return undefined
       }
 
+      if (isString(current) && isAlias(current)) return resolve(current, visited)
+
       result = current
     } else {
       if (isTokenAlias(current)) {