fix: isolate selected async values and namespace members

Author: Bill Leoutsakos

scripts/design-diff/README.md

@@ -150,7 +150,9 @@ does not establish equivalence of arbitrary interactive behavior.
 
 The resolver supports immutable constants, object properties, arrays, primitive template
 strings, simple arithmetic, conditional branches, static imports/re-exports, namespace
-imports, workspace exports and project `paths` aliases. It records CVA bases, variants,
+imports, workspace exports and project `paths` aliases. Static array selections and awaited
+`Promise.all` results trace the selected value independently; arbitrary promise failure and
+scheduling effects are not modeled. It records CVA bases, variants,
 defaults, compound variants and selections; runtime selections remain symbolic. Recognized
 `cn`/`clsx` helpers are interpreted as data. The trusted EMCN `cn` merge convention includes
 the repository's custom font-size groups. A helper with an unrecognized origin is not trusted

scripts/design-diff/resolve.ts

@@ -332,6 +332,13 @@ export class Resolver {
         }
         return initial
       }
+      if (binding?.path.isImportNamespaceSpecifier()) {
+        const declaration = binding.path.parentPath
+        if (declaration.isImportDeclaration()) {
+          const target = this.tree.resolve(file, declaration.node.source.value)
+          if (target) return this.exported(target, key, depth + 1)
+        }
+      }
       if (binding?.path.isImportSpecifier() || binding?.path.isImportDefaultSpecifier()) {
         const declaration = binding.path.parentPath
         if (declaration.isImportDeclaration()) {
@@ -348,6 +355,31 @@ export class Resolver {
         }
       }
     }
+    if (path.isAwaitExpression()) {
+      const awaited = child(path, 'argument')
+      if (awaited.isCallExpression()) {
+        const callee = child(awaited, 'callee')
+        if (
+          callee.isMemberExpression() &&
+          !callee.node.computed &&
+          t.isIdentifier(callee.node.object, { name: 'Promise' }) &&
+          !callee.scope.getBinding('Promise') &&
+          t.isIdentifier(callee.node.property, { name: 'all' })
+        ) {
+          const array = children(awaited, 'arguments')[0]
+          if (array?.isArrayExpression() && !array.node.elements.some(t.isSpreadElement)) {
+            const selected = this.selected(array, key, file, depth + 1, seen)
+            if (selected !== undefined) return { $await: selected }
+          }
+        }
+      }
+    }
+    if (path.isArrayExpression() && /^(?:0|[1-9]\d*)$/.test(key)) {
+      const elements = children(path, 'elements')
+      const index = Number(key)
+      if (index < elements.length && !elements.slice(0, index + 1).some((p) => p.isSpreadElement()))
+        return this.value(elements[index], file, depth + 1)
+    }
     if (path.isObjectExpression()) {
       for (const prop of children(path, 'properties').reverse()) {
         if (prop.isObjectMethod() && !prop.node.computed && propertyName(prop.node.key) === key)
@@ -357,7 +389,8 @@ export class Resolver {
         if (prop.isSpreadElement()) {
           const selected = this.selected(child(prop, 'argument'), key, file, depth + 1, seen)
           if (selected !== undefined) return selected
-          return undefined // An unknown later spread can override an earlier property.
+          /** An unknown later spread can override an earlier property. */
+          return undefined
         }
       }
     }
@@ -465,7 +498,10 @@ export class Resolver {
     if (!selection) return undefined
     const init = child(binding, 'init')
     const [first, ...rest] = selection.keys
-    let value = typeof first === 'string' ? this.selected(init, first, file, depth + 1) : undefined
+    let value =
+      typeof first === 'string' || typeof first === 'number'
+        ? this.selected(init, String(first), file, depth + 1)
+        : undefined
     const keys = value === undefined ? selection.keys : rest
     if (value === undefined) value = this.value(init, file, depth + 1)
     for (const key of keys) {
@@ -916,8 +952,8 @@ export class Resolver {
     if (t.isMemberExpression(node) || t.isOptionalMemberExpression(node)) {
       const key = node.computed ? read('property') : propertyName(node.property)
       const selected =
-        typeof key === 'string'
-          ? this.selected(child(path, 'object'), key, file, depth + 1)
+        typeof key === 'string' || typeof key === 'number'
+          ? this.selected(child(path, 'object'), String(key), file, depth + 1)
           : undefined
       if (selected !== undefined) return selected
       const base = read('object')

scripts/design-diff/tests/precision.test.ts

@@ -344,3 +344,42 @@ it('isolates unrelated mutable object fields such as telemetry warmup state', as
   )
   expect(report.flagged).toBe(false)
 })
+
+it.each(['[live, unrelated]', 'await Promise.all([live, unrelated])'])(
+  'projects an individual array result from %s',
+  async (expression) => {
+    const source = (colour: string, telemetry: number) =>
+      `export const live='${colour}';export const unrelated=${telemetry}`
+    const files = {
+      [data]: source('red', 1),
+      [view]: `import {live,unrelated} from './data';export async function Page(){const [colour]=${expression};return <span style={{color:colour}}/>}`,
+    }
+    expect((await compareFiles(files, { [data]: source('red', 2) }, settings)).flagged).toBe(false)
+    expect((await compareFiles(files, { [data]: source('blue', 1) }, settings)).flagged).toBe(true)
+  }
+)
+
+it('keeps shadowed Promise.all conservative', async () => {
+  const source = (n: number) => `export const unrelated=${n}`
+  const report = await compareFiles(
+    {
+      [data]: source(1),
+      [view]: `import {unrelated} from './data';export async function Page({Promise}){const [colour]=await Promise.all(['red',unrelated]);return <span style={{color:colour}}/>}`,
+    },
+    { [data]: source(2) },
+    settings
+  )
+  expect(report.flagged).toBe(true)
+})
+
+it('projects namespace members even when an outer expression reaches its resolution limit', async () => {
+  const source = (colour: string, unused: number) =>
+    `export const colour='${colour}';export const unused=${unused}`
+  const files = {
+    [data]: source('red', 1),
+    [view]: `import * as palette from './data';export const Page=()=> <span style={{color:unknown(unknown(unknown(palette.colour)))}}/>`,
+  }
+  const bounded = { ...settings, limits: { ...settings.limits, resolutionDepth: 2 } }
+  expect((await compareFiles(files, { [data]: source('red', 2) }, bounded)).flagged).toBe(false)
+  expect((await compareFiles(files, { [data]: source('blue', 1) }, bounded)).flagged).toBe(true)
+})