Beta 20: preserve saved Undo/Redo per project scene

.github/workflows/publish-unsigned-preview.yml

@@ -7,12 +7,12 @@ on:
         description: New prerelease tag; an existing release is never overwritten
         required: true
         type: string
-        default: v0.5.0-beta.19
+        default: v0.5.0-beta.20
       preview_title:
         description: Public prerelease title
         required: true
         type: string
-        default: Parlyn Engine v0.5.0 Beta 19 (unsigned)
+        default: Parlyn Engine v0.5.0 Beta 20 (unsigned)
 
 permissions:
   contents: write
@@ -24,8 +24,8 @@ jobs:
     env:
       CSC_IDENTITY_AUTO_DISCOVERY: false
       GH_TOKEN: ${{ github.token }}
-      PREVIEW_TAG: ${{ inputs.preview_tag || 'v0.5.0-beta.19' }}
-      PREVIEW_TITLE: ${{ inputs.preview_title || 'Parlyn Engine v0.5.0 Beta 19 (unsigned)' }}
+      PREVIEW_TAG: ${{ inputs.preview_tag || 'v0.5.0-beta.20' }}
+      PREVIEW_TITLE: ${{ inputs.preview_title || 'Parlyn Engine v0.5.0 Beta 20 (unsigned)' }}
 
     steps:
       - name: Checkout
@@ -55,7 +55,7 @@ jobs:
             throw "Expected exactly one Parlyn installer."
           }
 
-          $portable = "release/Parlyn-Engine-Portable-0.5.0-beta.19-x64.zip"
+          $portable = "release/Parlyn-Engine-Portable-0.5.0-beta.20-x64.zip"
           if (-not (Test-Path -LiteralPath "release/win-unpacked/Parlyn Engine.exe")) {
             throw "Packaged Parlyn executable was not found for the portable build."
           }
@@ -72,14 +72,14 @@ jobs:
         shell: pwsh
         run: |
           @"
-          # Parlyn Engine v0.5.0 Beta 19
-
-          This unsigned Windows beta adds optional scene and world bounds as
-          world-space authoring guides through the Bounds command. Scene bounds
-          use normal saving and Undo/Redo; world bounds are explicitly saved.
-          Bounds do not constrain objects, cameras or runtime physics.
-          Beta 18 passed the maintainer's full editor regression test; Beta 19
-          awaits human Windows acceptance. Older editors discard bounds on save.
+          # Parlyn Engine v0.5.0 Beta 20
+
+          This unsigned Windows beta fixes saved Undo/Redo disappearing after
+          switching project scenes. History is stored independently per scene.
+          It retains Beta 19's optional scene and world authoring bounds.
+          Beta 19 was not accepted due to the history defect; Beta 20 awaits
+          human Windows acceptance. Previously overwritten history cannot be
+          reconstructed. Older editors discard bounds on save.
           The portable ZIP creates no Windows installation or uninstall entry and
           remains the preferred unsigned test path.
 
@@ -96,7 +96,7 @@ jobs:
           other public certificate provider.
 
           Maintainer acceptance instructions:
-          https://github.com/WebCrew/Parlyn-Engine/blob/main/docs/MAINTAINER-ACCEPTANCE-v0.5.0-beta.19.md
+          https://github.com/WebCrew/Parlyn-Engine/blob/main/docs/MAINTAINER-ACCEPTANCE-v0.5.0-beta.20.md
           "@ | Set-Content -LiteralPath release/PREVIEW-NOTES.md -Encoding utf8
 
       - name: Publish GitHub pre-release
@@ -114,6 +114,6 @@ jobs:
             --notes-file release/PREVIEW-NOTES.md `
             --prerelease `
             "$($installer[0].FullName)" `
-            "release/Parlyn-Engine-Portable-0.5.0-beta.19-x64.zip" `
+            "release/Parlyn-Engine-Portable-0.5.0-beta.20-x64.zip" `
             "release/latest.yml" `
             "release/SHA256SUMS.txt"

CHANGES.md

@@ -2,6 +2,14 @@
 
 ## Unreleased — Foundation Stabilization
 
+- Beta 20: fixed project scenes overwriting one shared history file. Saved
+  Undo/Redo now uses a separate hashed path per scene, with read-only legacy
+  fallback and unchanged stale-snapshot/size validation.
+- Added a real file-system regression test for A/B switching, same-name scenes
+  in different folders, saved Redo, legacy history and corrupt/stale rejection.
+- Beta 19 remains unaccepted following the maintainer's history defect report;
+  Beta 20 awaits re-testing. Already overwritten history cannot be recovered.
+
 - Beta 19: added optional validated scene/world authoring bounds, independent
   of viewport size, with separate blue/amber guides and explicit world saving.
 - Added scene bounds Undo/Redo and round-trip/validation/helper-lifecycle tests.

README.md

@@ -6,11 +6,13 @@
 
 # Parlyn Engine
 
-Beta 19 adds optional scene/world bounds through **Bounds** in the View command
+Beta 20 fixes saved per-scene Undo/Redo history after a scene switch. It retains
+Beta 19's optional scene/world bounds through **Bounds** in the View command
 group: blue scene guides and amber world guides in world coordinates. They do
 not restrict camera movement, objects or physics. Scene edits use Undo/Redo and
-normal Save; world edits use explicit Save World Bounds. Human Beta 19 Windows
-acceptance is pending. Beta 18 passed the full maintainer editor regression test.
+normal Save; world edits use explicit Save World Bounds. Beta 19 was not accepted
+due to the history defect; Beta 20 human Windows acceptance is pending.
+Beta 18 passed the full maintainer editor regression test.
 
 **Parlyn Engine** is a free and open-source game engine designed primarily for **modern 2.5D development**, while keeping real 3D available wherever a project benefits from it.
 
@@ -235,7 +237,7 @@ See [`docs/WINDOWS-DISTRIBUTION.md`](docs/WINDOWS-DISTRIBUTION.md) for signing,
 verification and the maintainer acceptance test.
 
 Phase 1 acceptance is complete. The current Phase 2 editor candidate uses the
-repeatable [`v0.5.0-beta.19 maintainer checklist`](docs/MAINTAINER-ACCEPTANCE-v0.5.0-beta.19.md).
+repeatable [`v0.5.0-beta.20 maintainer checklist`](docs/MAINTAINER-ACCEPTANCE-v0.5.0-beta.20.md).
 
 ### Windows release integrity
 

docs/MAINTAINER-ACCEPTANCE-v0.5.0-beta.19.md

@@ -3,6 +3,10 @@
 Status: pending human Windows acceptance. Beta 18 passed the maintainer's full
 editor regression test on 2026-09-12.
 
+Beta 19 was not accepted: the maintainer found saved Undo history disappearing
+after switching project scenes. Beta 20 addresses the shared-history-file cause
+and requires the dedicated per-scene history re-test before acceptance.
+
 1. Open an existing project. Bounds are initially absent. Open **Bounds** in
    the View command group; check tooltips, keyboard focus and readable labels.
 2. Enable Current Scene bounds, enter Min (-10,-3,-10), Max (10,8,10), and

docs/MAINTAINER-ACCEPTANCE-v0.5.0-beta.20.md

@@ -0,0 +1,27 @@
+# Parlyn Engine v0.5.0 Beta 20 — Maintainer Acceptance
+
+Status: pending human Windows acceptance. Beta 19 was not accepted because
+saving a second project scene overwrote the first scene's local history.
+Beta 20 separates saved history by project-relative scene path.
+
+Use a disposable copy of a project with two scenes.
+
+1. In scene A enable/change Bounds, Apply and Save. Undo must remain enabled.
+2. Switch to B, enable different Bounds, Apply and Save.
+3. Switch back to A. Undo must still be enabled and undo A's Bounds edit only.
+4. Redo restores A's exact values. Save A, switch to B: B's Undo must still work
+   independently. Repeat A/B switching several times.
+5. Undo an edit, Save, switch away and return: Redo must remain available if no
+   new edit was made. A new edit after Undo must clear only that scene's Redo.
+6. Save both scenes, close the project and Engine, restart and reopen. Each
+   saved scene must retain its own Undo/Redo state. Include transform edits.
+7. Test scene names that are identical but live in different subfolders.
+8. Repeat the Bounds checks in [Beta 19's checklist](MAINTAINER-ACCEPTANCE-v0.5.0-beta.19.md), including loose-scene persistence and World Bounds.
+9. Re-test unsaved Cancel/Discard/Save & Continue, snapping, Ground/End,
+   Frame Selected/F, multi-selection and panel restoration.
+
+History reflects its last successful save, not unsaved actions intentionally
+discarded during switching. Already overwritten Beta 19 history cannot be
+reconstructed by this fix. A matching legacy history remains readable until
+the next save writes a separate per-scene file. Renamed/moved scene paths
+have separate history identities; stale history is never attached blindly.

docs/PROJECT-FORMAT.md

@@ -58,8 +58,13 @@ Contains source assets imported by the developer. External asset formats are not
 ## `.parlyn/`
 
 Reserved for generated caches, import metadata and other project-local internal
-data. Beta 5 stores the validated startup Scene History here as
-`startup-scene.parlyn-history.json`. Developers should not rely on internal
+data. Beta 20 stores validated per-scene History under
+`scene-history/<sha256-of-project-relative-scene-path>.parlyn-history.json`.
+The previous shared `startup-scene.parlyn-history.json` is read-only legacy
+fallback, accepted only for its matching scene and snapshot. New saves never
+overwrite that legacy file. History remains limited to 100 entries and the
+existing size limits. Renamed/moved paths have separate history identities.
+Developers should not rely on internal
 paths as a public API; the history document itself remains explicitly versioned.
 
 ## Compatibility contract v1

docs/ROADMAP.md

@@ -49,6 +49,7 @@ Completion evidence:
 
 - duplication and reparenting — initial editor commands complete;
 - durable, validated local Scene History — initial foundation complete;
+  Beta 20 corrects saved per-scene history isolation; human re-test pending;
 - multi-selection where appropriate — initial hierarchy and viewport selection complete;
 - multi-scene project browser — validated listing, switching, creation, rename and move complete;
 - rename and move project assets — initial safe editor workflow complete;

docs/TESTING-v0.5.0.md

@@ -1,7 +1,7 @@
 # Parlyn Engine v0.5.0 Test Guide
 
 For the current Phase 2 editor acceptance pass, use the shorter artifact-specific
-[`MAINTAINER-ACCEPTANCE-v0.5.0-beta.19.md`](MAINTAINER-ACCEPTANCE-v0.5.0-beta.19.md)
+[`MAINTAINER-ACCEPTANCE-v0.5.0-beta.20.md`](MAINTAINER-ACCEPTANCE-v0.5.0-beta.20.md)
 The guide below remains the detailed feature reference.
 
 This test focuses on the two new foundations introduced in v0.5.0: viewport transform gizmos and the module lifecycle.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "parlyn-engine",
-  "version": "0.5.0-beta.19",
+  "version": "0.5.0-beta.20",
   "private": true,
   "description": "Parlyn Engine - open-source 2.5D-first game engine editor",
   "author": "Parlyn Engine contributors",

scripts/check-desktop-boundaries.cjs

@@ -100,7 +100,11 @@ const { resolveExistingProjectPath, resolveWritableProjectPath, resolveWritableP
   assert.match(main, /secureHandle\('parlyn:project:move-asset'/);
   assert.match(main, /secureHandle\('parlyn:project:close'/);
   assert.match(main, /secureHandle\('parlyn:project:delete'/);
-  assert.match(main, /parlyn-scene-history/);
+  const sceneHistoryFiles = await fs.readFile(path.join(__dirname, '../src/main/sceneHistoryFiles.mjs'), 'utf8');
+  assert.match(main, /import\('\.\/sceneHistoryFiles\.mjs'\)/);
+  assert.match(main, /\.loadSceneHistory\(projectRoot, sceneRelativePath, currentScene\)/);
+  assert.match(main, /\.saveSceneHistory\(activeProjectRoot, relativePath, payload\.scene, payload\.history\)/);
+  assert.match(sceneHistoryFiles, /parlyn-scene-history/);
   assert.match(renderer, /history\.exportState\(/);
   assert.match(renderer, /history\.restoreState\(result\.history\)/);
   assert.match(renderer, /normalizeWorkspaceLayout/);

scripts/check-scene-history-files.mjs

@@ -0,0 +1,65 @@
+import assert from 'node:assert/strict';
+import fs from 'node:fs/promises';
+import os from 'node:os';
+import path from 'node:path';
+import { SceneDocument } from '../src/engine/scene/SceneDocument.mjs';
+import { History } from '../src/engine/history/History.mjs';
+import { sceneHistoryRelativePath, saveSceneHistory, loadSceneHistory } from '../src/main/sceneHistoryFiles.mjs';
+import { readDocumentFile, writeDocumentFileAtomic } from '../src/main/documentFiles.mjs';
+
+const root = await fs.mkdtemp(path.join(os.tmpdir(), 'parlyn-per-scene-history-'));
+try {
+  const emptyRoot = path.join(root, 'empty');
+  await fs.mkdir(emptyRoot);
+  assert.deepEqual(await loadSceneHistory(emptyRoot, 'scenes/new.json', new SceneDocument().toJSON()), { history:null, warning:null });
+  const entries = ['scenes/first/Demo.parlyn-scene.json', 'scenes/second/Demo.parlyn-scene.json'].map((scenePath, index) => {
+    const scene = new SceneDocument(`Demo ${index}`);
+    const before = scene.toJSON();
+    scene.bounds = { min:{ x:-10-index, y:-3, z:-10 }, max:{ x:10+index, y:8, z:10 } };
+    const history = new History(); history.push(before, 'Change Scene Bounds');
+    return { scenePath, scene, before, history };
+  });
+  assert.notEqual(sceneHistoryRelativePath(entries[0].scenePath), sceneHistoryRelativePath(entries[1].scenePath));
+  for (const entry of entries) {
+    const file = path.join(root, entry.scenePath);
+    await fs.mkdir(path.dirname(file), { recursive:true });
+    await writeDocumentFileAtomic(file, entry.scene.toJSON(), 'parlyn-scene');
+    await saveSceneHistory(root, entry.scenePath, entry.scene.toJSON(), entry.history.exportState());
+  }
+  // Save A, save B, reopen A, reopen B: each scene retains its own Undo.
+  for (const entry of entries) {
+    const scene = await readDocumentFile(path.join(root, entry.scenePath), 'parlyn-scene');
+    const result = await loadSceneHistory(root, entry.scenePath, scene);
+    assert.equal(result.warning, null);
+    const restored = new History(); restored.restoreState(result.history);
+    assert.equal(restored.canUndo, true);
+    assert.deepEqual(restored.undo(scene).snapshot, entry.before);
+    assert.deepEqual(restored.redo(entry.before).snapshot, scene);
+  }
+  // Persist an Undo followed by a switch/reopen: Redo is retained too.
+  const first = entries[0];
+  first.history.undo(first.scene.toJSON());
+  await saveSceneHistory(root, first.scenePath, first.before, first.history.exportState());
+  const redoResult = await loadSceneHistory(root, first.scenePath, first.before);
+  const redoHistory = new History(); redoHistory.restoreState(redoResult.history);
+  assert.equal(redoHistory.canRedo, true);
+  assert.deepEqual(redoHistory.redo(first.before).snapshot, first.scene.toJSON());
+  assert.equal((await loadSceneHistory(root, first.scenePath, first.scene.toJSON())).history, null, 'Stale history remains rejected.');
+  assert.throws(() => sceneHistoryRelativePath('../outside.json'));
+
+  // Legacy history is read-only, accepted only when path and snapshot match.
+  const legacy = path.join(root, '.parlyn/startup-scene.parlyn-history.json');
+  await writeDocumentFileAtomic(legacy, { format:'parlyn-scene-history', version:1,
+    scenePath:'scenes/legacy.json', currentScene:first.before, history:new History().exportState(), updatedAt:new Date().toISOString() }, 'parlyn-scene-history');
+  assert.notEqual((await loadSceneHistory(root, 'scenes/legacy.json', first.before)).history, null);
+  assert.equal((await loadSceneHistory(root, 'scenes/other.json', first.before)).history, null);
+  const legacyBefore = await fs.readFile(legacy, 'utf8');
+  await saveSceneHistory(root, 'scenes/legacy.json', first.before, new History().exportState());
+  assert.equal(await fs.readFile(legacy, 'utf8'), legacyBefore, 'New saves must not overwrite legacy history.');
+  const primary = path.join(root, sceneHistoryRelativePath('scenes/legacy.json'));
+  await fs.writeFile(primary, '{broken', 'utf8');
+  assert.equal((await loadSceneHistory(root, 'scenes/legacy.json', first.before)).history, null, 'Corrupt primary must not fall back to an older legacy snapshot.');
+} finally {
+  await fs.rm(root, { recursive:true, force:true });
+}
+console.log('Per-scene saved Undo/Redo history regression check passed.');

scripts/check-windows-distribution.cjs

@@ -37,7 +37,7 @@ requireValue(workflow.includes('Verify signed Windows artifacts'), 'Signed outpu
 requireValue(workflow.includes('require_signing'), 'Windows workflow must distinguish signed and unsigned preflight builds.');
 requireValue(!workflow.includes('BEGIN PRIVATE KEY'), 'Signing material must never be embedded in the workflow.');
 requireValue(previewWorkflow.includes('Compress-Archive'), 'Unsigned previews must create a portable ZIP test artifact.');
-requireValue(previewWorkflow.includes('Parlyn-Engine-Portable-0.5.0-beta.19-x64.zip'), 'Portable preview artifact has an unexpected name.');
+requireValue(previewWorkflow.includes('Parlyn-Engine-Portable-0.5.0-beta.20-x64.zip'), 'Portable preview artifact has an unexpected name.');
 requireValue(previewWorkflow.includes('release/win-unpacked/Parlyn Engine.exe'), 'Portable preview must verify its packaged executable.');
 
 const gitignore = fs.readFileSync(path.join(root, '.gitignore'), 'utf8');

scripts/check.cjs

@@ -64,6 +64,9 @@ const required = [
   'scripts/check-transform-space.mjs',
   'scripts/check-frame-selected.mjs',
   'scripts/check-document-bounds.mjs',
+  'scripts/check-scene-history-files.mjs',
+  'src/main/sceneHistoryFiles.mjs',
+  'docs/MAINTAINER-ACCEPTANCE-v0.5.0-beta.20.md',
   'src/engine/core/DocumentBounds.mjs',
   'docs/MAINTAINER-ACCEPTANCE-v0.5.0-beta.19.md',
   'scripts/check-asset-files.cjs',
@@ -78,7 +81,7 @@ for (const rel of required) {
 
 const pkg = JSON.parse(fs.readFileSync(path.join(root, 'package.json'), 'utf8'));
 if (pkg.name !== 'parlyn-engine') throw new Error('Unexpected package name.');
-if (pkg.version !== '0.5.0-beta.19') throw new Error(`Unexpected package version: ${pkg.version}`);
+if (pkg.version !== '0.5.0-beta.20') throw new Error(`Unexpected package version: ${pkg.version}`);
 
 function walk(dir) {
   return fs.readdirSync(dir, { withFileTypes: true }).flatMap((entry) => {
@@ -105,6 +108,7 @@ cp.execFileSync(process.execPath, [path.join(root, 'scripts/check-transform-snap
 cp.execFileSync(process.execPath, [path.join(root, 'scripts/check-transform-space.mjs')], { stdio: 'inherit' });
 cp.execFileSync(process.execPath, [path.join(root, 'scripts/check-frame-selected.mjs')], { stdio: 'inherit' });
 cp.execFileSync(process.execPath, [path.join(root, 'scripts/check-document-bounds.mjs')], { stdio: 'inherit' });
+cp.execFileSync(process.execPath, [path.join(root, 'scripts/check-scene-history-files.mjs')], { stdio: 'inherit' });
 cp.execFileSync(process.execPath, [path.join(root, 'scripts/check-asset-files.cjs')], { stdio: 'inherit' });
 cp.execFileSync(process.execPath, [path.join(root, 'scripts/check-windows-distribution.cjs')], { stdio: 'inherit' });