[Bug]: Refresh in explorer doesn't see new files

[mattcasters]

Apache Hop version?

2.19.0-SNAPSHOT

Java version?

OpenJDK 21

Operating system

Windows

What happened?

Seen on windows/linux but now always.

If a workflow or pipeline creates files in the project, they are not found in the explorer panel. Even using the refresh button in the toolbar above it doesn't bring these new files/folders to light.

Issue Priority

Priority: 2

Issue Component

Component: Hop Gui

[mattcasters]

Root cause analysis

Hard to reproduce because several conditions must line up: selection elsewhere, folders already expanded once, and (sometimes) a stale VFS directory listing.

1. Scoped F5 only refreshed the last selected folder (primary)

After #7426 / #7364, toolbar refresh / F5 preferred scoped refresh of lastSelectedFolderPath whenever anything had been selected in the tree (folder, or parent of a selected file).

So if you were looking at pipelines/ while a pipeline wrote under output/, F5 only re-listed pipelines/. New folders/files elsewhere never entered the SWT tree.

refresh()
  → treeModel.clear()
  → if lastSelectedFolderPath set → refreshSelectedFolder()  // only one folder
  → else refreshEntireTree()

That matches “even the refresh button doesn’t bring them to light.”

2. Lazy loaded flag never re-scanned already-loaded folders

Once a folder had been expanded, TreeItemFolder.loaded = true and ensureFolderLoaded() returned without calling VFS again:

if (tif.loaded && !hasOnlyLazyDummyChild(item)) {
  return; // never re-lists from disk
}

Typical intermittent scenario:

1. Expand folder A once → children snapshotted in the tree.
2. Pipeline creates A/new-folder/ or new files under A.
3. Selection is elsewhere → F5 only refreshes the selected folder.
4. Looking at A again (or collapse/expand) does not re-read the filesystem.

Empty folders that were already loaded with zero children are worse: no expand icon, nothing ever reloads until that path is scoped-refreshed or the whole tree is rebuilt.

3. Commons VFS children cache (contributing)

Hop uses SoftRefFilesCache + CacheStrategy.ON_RESOLVE. AbstractFileObject.getChildren() caches child names until FileObject.refresh(). External writes (pipelines, other processes) that do not go through the same FileObject graph leave listings dependent on that cache/refresh path. Explorer never called refresh() before listing.

4. Filter index (ExplorerTreeModel) — secondary

The in-memory filter model (#7783) is cleared on refresh(); while filtering, F5 re-indexes. Secondary to the UI tree issue above, but the fix also forces fresh VFS lists when building that model.

Fix (PR)

• Toolbar F5 = hard refresh of the entire tree (filter index cleared; expand state restored via TreeMemory).
• listChildrenFresh(): HopVfs.getFileObject + FileObject.refresh() + getChildren() for tree and filter walks.
• Context menu Refresh folder keeps cheap scoped refresh for intentional single-folder updates.
• Path equality helper for mixed \// (Windows).

PR: will link shortly after open.

[mattcasters]

Fix PR: #7798