1 files changed, 20 insertions, 3 deletions
diff --git a/modules/core/virtual-fs.js b/modules/core/virtual-fs.js
index 3a3e119..57c6578 100644
--- a/modules/core/virtual-fs.js
+++ b/modules/core/virtual-fs.js
@@ -510,6 +510,19 @@ class VirtualFileSystem {
         }
         return { dir, name: segs[segs.length - 1] };
     }
+    // newOS4 patch: _resolvePath() validates intermediate segments only, so it returns a
+    // result for a leaf that does not exist. Mutating callers then acted on a phantom
+    // path and reported success (deleteCheckpoint printed 'Deleted checkpoint' and
+    // deleted nothing). _requireLeaf() refuses any resolved path whose leaf is absent.
+    _requireLeaf(resolved) {
+        if (!resolved) return null;
+        if (resolved.name) {
+            const node = (resolved.dir && resolved.dir.content) ? resolved.dir.content[resolved.name] : null;
+            if (!node) return null;
+        }
+        return resolved;
+    }
+
     _resolveDir(path) {
         if (this._isVirtualPath(path)) {
             const r = this._resolveVirtualPath(path);
@@ -579,7 +592,7 @@ class VirtualFileSystem {
     }
     deleteFile(path) {
         if (this._isVirtualPath(path)) return false;
-        const resolved = this._resolvePath(path);
+        const resolved = this._requireLeaf(this._resolvePath(path));
         if (!resolved || !resolved.name) return false;
         const node = resolved.dir.content[resolved.name];
         if (node && node.type === 'file') {
@@ -966,6 +979,10 @@ class VirtualFileSystem {
             delete rootClone.content['_sessions'];
             delete rootClone.content['_snapshots'];
             delete rootClone.content['.trash'];
+            // newOS4 patch: module originals and the semantic index dominated every
+            // snapshot (one checkpoint reached 4.13MB) and grew on each new checkpoint.
+            delete rootClone.content['_mods'];
+            delete rootClone.content['.semantic_index'];
         }
         const data = {
             version: 1,
@@ -1000,7 +1017,7 @@ class VirtualFileSystem {
         // clone verbatim deletes every checkpoint, every agent session and the trash, so keep the
         // live copies and re-attach them after the root swap.
         const keep = {};
-        for (const dir of ['_snapshots', '_sessions', '.trash']) {
+        for (const dir of ['_snapshots', '_sessions', '.trash', '_mods', '.semantic_index']) {
             const node = this.root && this.root.content ? this.root.content[dir] : null;
             if (node) keep[dir] = node;
         }
@@ -1020,7 +1037,7 @@ class VirtualFileSystem {
     }
     deleteCheckpoint(name) {
         const path = '/_snapshots/checkpoint-' + name + '.json';
-        const resolved = this._resolvePath(path);
+        const resolved = this._requireLeaf(this._resolvePath(path));
         if (resolved && resolved.name) {
             delete resolved.dir.content[resolved.name];
             this.saveToStorage();