fix(workspace-context): reconcile resumed baselines

packages/context/workspace-context/src/files.ts

@@ -46,12 +46,14 @@ interface DiscoverOptions {
   projectRootMarkers?: string[]
   instructionFileCandidates?: string[]
   localInstructionFileCandidates?: string[]
+  projectRoot?: string
   signal?: AbortSignal
 }
 
 interface LoadOptions extends DiscoverOptions {
   maxBytes: number
   maxSourceBytes?: number
+  replacePreviousBaseline?: boolean
 }
 
 /** Rendered baseline plus the files that survived byte budgeting. */
@@ -286,7 +288,8 @@ async function discoverInstructionFiles(
   }
 
   const cwd = resolve(options.cwd)
-  const projectRoot = await findProjectRoot(cwd, config.projectRootMarkers, fileSystem, options.signal)
+  const projectRoot = options.projectRoot
+    ?? await findProjectRoot(cwd, config.projectRootMarkers, fileSystem, options.signal)
   for (const dir of ancestorChain(projectRoot, cwd)) {
     for (const candidates of [config.instructionFileCandidates, config.localInstructionFileCandidates]) {
       for (const file of await allExistingInstructionFiles(dir, projectRoot, candidates, fileSystem, options.signal)) {
@@ -389,7 +392,7 @@ export async function loadBaselineInstructions(
  * Load a baseline together with the files retained after rendering.
  * @param options - discovery, source-size, byte-budget, and cancellation configuration.
  * @param fileSystem - optional provider used instead of host filesystem reads.
- * @returns rendered context and retained files, or undefined when empty or disabled.
+ * @returns rendered context and retained files, an explicit empty replacement set, or undefined when empty or disabled.
  */
 export async function loadBaselineInstructionSet(
   options: LoadOptions,
@@ -412,8 +415,22 @@ export async function loadBaselineInstructionSet(
     }
   }
   const deduped = dedupInstructionFilesByDirectory(loaded)
-  if (deduped.length === 0) return undefined
-  const rendered = renderWorkspaceContext(deduped, { maxBytes: config.maxBytes })
+  if (deduped.length === 0) {
+    if (options.replacePreviousBaseline !== true) return undefined
+    return {
+      rendered: renderWorkspaceContext([], {
+        maxBytes: config.maxBytes,
+        replacePreviousBaseline: true,
+      }),
+      included: [],
+    }
+  }
+  const rendered = renderWorkspaceContext(deduped, {
+    maxBytes: config.maxBytes,
+    ...options.replacePreviousBaseline === undefined
+      ? {}
+      : { replacePreviousBaseline: options.replacePreviousBaseline },
+  })
   const omitted = new Set(rendered.omitted.map(file => file.absolutePath))
   return { rendered, included: deduped.filter(file => !omitted.has(file.absolutePath)) }
 }