fix(studio): survive damaged package meta; clean up OPFS write husks

lp-app/lpa-fs-opfs/src/opfs_write.rs

@@ -25,6 +25,12 @@ fn split_parent(path: &LpPath) -> (String, String) {
 
 /// Write `bytes` to `path` (absolute lp-style) below `root`, creating parent
 /// directories as needed. Atomic per file (commit happens at close).
+///
+/// The atomic swap only protects *content* — `getFileHandle(create)` makes
+/// the entry itself immediately. A write that fails after creation would
+/// otherwise leave a persistent empty husk (seen on iOS Safari, where a
+/// jetsammed tab can abandon a flush mid-file), so a failed write to a file
+/// that did not previously exist removes the husk best-effort.
 pub async fn write_file(
     root: &FileSystemDirectoryHandle,
     path: &LpPath,
@@ -33,6 +39,8 @@ pub async fn write_file(
     let (parent_path, name) = split_parent(path);
     let parent = open_dir(root, &parent_path, true).await?;
 
+    let existed = JsFuture::from(parent.get_file_handle(&name)).await.is_ok();
+
     let options = FileSystemGetFileOptions::new();
     options.set_create(true);
     let handle = JsFuture::from(parent.get_file_handle_with_options(&name, &options))
@@ -42,6 +50,20 @@ pub async fn write_file(
         .dyn_into()
         .map_err(|e| OpfsError::new("get_file_handle", path.as_str().to_string(), e))?;
 
+    let result = write_via_writable(&handle, path, bytes).await;
+    if result.is_err() && !existed {
+        let _ = JsFuture::from(parent.remove_entry(&name)).await;
+    }
+    result
+}
+
+/// The stage-and-swap half of [`write_file`]: create a writable, write,
+/// close (the commit point).
+async fn write_via_writable(
+    handle: &FileSystemFileHandle,
+    path: &LpPath,
+    bytes: &[u8],
+) -> Result<(), OpfsError> {
     let stream = JsFuture::from(handle.create_writable())
         .await
         .map_err(|e| OpfsError::new("create_writable", path.as_str().to_string(), e))?;

lp-app/lpa-studio-core/src/app/library/package_meta.rs

@@ -54,9 +54,17 @@ pub fn read_meta(fs: &dyn LpFs) -> Result<Option<PackageMeta>, LibraryError> {
     let bytes = fs
         .read_file(META_PATH.as_path())
         .map_err(|e| LibraryError::Meta(format!("read meta: {e}")))?;
-    serde_json::from_slice(&bytes)
-        .map(Some)
-        .map_err(|e| LibraryError::Meta(format!("parse meta: {e}")))
+    // Lenient parse: provenance is a best-effort sidecar, and browser
+    // storage can leave it torn or zero-filled (an iOS Safari tab killed
+    // mid-flush). Treating damage as "absent" keeps it from bricking
+    // project open — the origin event falls back to `Created`.
+    match serde_json::from_slice(&bytes) {
+        Ok(meta) => Ok(Some(meta)),
+        Err(e) => {
+            log::warn!("package meta unreadable (treating as absent): parse meta: {e}");
+            Ok(None)
+        }
+    }
 }
 
 pub fn write_meta(fs: &dyn LpFs, meta: &PackageMeta) -> Result<(), LibraryError> {
@@ -84,4 +92,17 @@ mod tests {
         write_meta(&fs, &meta).unwrap();
         assert_eq!(read_meta(&fs).unwrap().unwrap(), meta);
     }
+
+    #[test]
+    fn damaged_meta_reads_as_absent() {
+        use lpc_model::AsLpPath;
+        let fs = LpFsMemory::new();
+        // Zero-filled sidecar: the signature of a browser tab killed
+        // mid-flush (size persisted, content lost).
+        fs.write_file(META_PATH.as_path(), &[0u8; 64]).unwrap();
+        assert!(read_meta(&fs).unwrap().is_none());
+        // Empty husk (created, never committed).
+        fs.write_file(META_PATH.as_path(), &[]).unwrap();
+        assert!(read_meta(&fs).unwrap().is_none());
+    }
 }