Native surfaces migration — evolve the extension onto VS Code's native review surfaces (9-task plan, spec v0.2.1) (#72)

src/baselineStore.ts

@@ -7,11 +7,19 @@
  * key is a hash of the document URI (the controller derives it), not a
  * workspace-relative path; an untitled buffer has no durable identity and is
  * never persisted here (in-memory only — see DiffViewController).
+ *
+ * INV-7 (native-surfaces migration, spec §6.4): the baseline is now either the
+ * git-HEAD blob (never persisted — see GitBaselineAdapter/DiffViewController)
+ * or a snapshot captured on coediting-entry / re-pinned by "Mark Changes as
+ * Reviewed". `"opened"`/`"machine-landing"` are legacy reasons from the
+ * shipped #17/#48 baseline; `normalizeReason` migrates them on load so old
+ * on-disk baselines keep round-tripping under the new vocabulary.
  */
 import * as fs from "node:fs";
 import * as path from "node:path";
 
-export type BaselineReason = "opened" | "machine-landing" | "pinned";
+export type BaselineReason = "entered" | "pinned" | "head";
+type LegacyBaselineReason = BaselineReason | "opened" | "machine-landing";
 
 export interface Baseline {
   /** the document URI (the identity the key is derived from) — for round-trip/debug. */
@@ -22,6 +30,12 @@ export interface Baseline {
   reason: BaselineReason;
 }
 
+/** Migrate legacy on-disk reasons to the current vocabulary (§6.4 INV-7). */
+export function normalizeReason(reason: LegacyBaselineReason): BaselineReason {
+  if (reason === "opened" || reason === "machine-landing") return "entered";
+  return reason;
+}
+
 export class BaselineStore {
   /** @param storageDir absolute VS Code GLOBAL-storage dir (context.globalStorageUri.fsPath). */
   constructor(private readonly storageDir: string) {}
@@ -34,7 +48,8 @@ export class BaselineStore {
   load(key: string): Baseline | null {
     const p = this.baselinePath(key);
     if (!fs.existsSync(p)) return null;
-    return JSON.parse(fs.readFileSync(p, "utf8")) as Baseline;
+    const raw = JSON.parse(fs.readFileSync(p, "utf8")) as Baseline;
+    return { ...raw, reason: normalizeReason(raw.reason) };
   }
 
   /** Newest epoch wins — overwrite in place, no history (state-not-history, the F3/F4 precedent). */