fix(diagnostics): prevent startup request deadlocks

Author: hongjr03

crates/vfs/src/loader.rs

@@ -44,7 +44,18 @@ pub struct Config {
 /// Messages sent by a loader generation back to the main loop.
 pub enum Message {
     Progress { n_total: usize, n_done: usize, config_version: u32 },
-    Loaded { files: Vec<(AbsPathBuf, LoadResult)>, config_version: u32 },
+    Loaded { files: Vec<(AbsPathBuf, LoadResult)>, config_version: u32, origin: LoadOrigin },
+}
+
+/// The boundary that caused a batch of file contents to be loaded.
+///
+/// Keeping this explicit prevents an initial configuration scan from being
+/// mistaken for an external file-system change by downstream consumers.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum LoadOrigin {
+    ConfigScan,
+    ExplicitInvalidate,
+    FileWatcher,
 }
 
 pub type Sender = crossbeam_channel::Sender<Message>;
@@ -126,10 +137,11 @@ impl Directories {
 impl fmt::Debug for Message {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
-            Message::Loaded { files, config_version } => f
+            Message::Loaded { files, config_version, origin } => f
                 .debug_struct("Loaded")
                 .field("n_files", &files.len())
                 .field("config_version", config_version)
+                .field("origin", origin)
                 .finish(),
             Message::Progress { n_total, n_done, config_version } => f
                 .debug_struct("Progress")