Fix bug with reimporting test cases

When re-importing a test database, if the source archive for that
database is not in the workspace, then old source code will be seen when
inspected.

To reproduce:

1. Run a ql test file with a failure (I'm using a javascript DB).
2. Right click and import on the db that sticks around.
3. Change the JS source file for the test.
4. Re-run and still have a failure.
5. Re-import the database
6. Run the query under test
7. Click on a result item
8. **BUG:** The source code is old

The problem is that the source archive cache is not being flushed in
this case. I added a case to flush the source archive when the archive
was imported into the workspace as a folder, but not when the archive is
external.

The fix is to listen for database remove events in the archive
filesystem provider and flush the associated database source
archive.

There is a complication:

The database remove event didn't emit the removed database. This is
because the only place that consumed the event didn't need it.

To get around this, I changed the structure of the events. I added a
new `fullRefresh` boolean. If true, then the original database change
handler will ensure the entire tree is refreshed. If false, only the
selected database.

extensions/ql-vscode/src/common/vscode/archive-filesystem-provider.ts

@@ -26,6 +26,8 @@ import {
 // All path operations in this file must be on paths *within* the zip
 // archive.
 import { posix } from "path";
+import { DatabaseEventKind } from "../../databases/local-databases/database-events";
+import type { DatabaseManager } from "../../databases/local-databases/database-manager";
 
 const path = posix;
 
@@ -242,15 +244,10 @@ export class ArchiveFileSystemProvider implements FileSystemProvider {
 
   root = new Directory("");
 
-  constructor() {
-    // When a file system archive is removed from the workspace, we should
-    // also remove it from our cache.
-    workspace.onDidChangeWorkspaceFolders((event) => {
-      for (const removed of event.removed) {
-        const zipPath = removed.uri.fsPath;
-        this.archives.delete(zipPath);
-      }
-    });
+  constructor() {}
+
+  flushCache(zipPath: string) {
+    this.archives.delete(zipPath);
   }
 
   // metadata
@@ -366,15 +363,33 @@ export class ArchiveFileSystemProvider implements FileSystemProvider {
  */
 export const zipArchiveScheme = "codeql-zip-archive";
 
-export function activate(ctx: ExtensionContext) {
+export function activate(ctx: ExtensionContext, dbm: DatabaseManager) {
+  const afsp = new ArchiveFileSystemProvider();
   ctx.subscriptions.push(
-    workspace.registerFileSystemProvider(
-      zipArchiveScheme,
-      new ArchiveFileSystemProvider(),
-      {
-        isCaseSensitive: true,
-        isReadonly: true,
-      },
-    ),
+    dbm.onDidChangeDatabaseItem(async ({ kind, item: db }) => {
+      if (kind === DatabaseEventKind.Remove) {
+        if (db?.sourceArchive) {
+          afsp.flushCache(db.sourceArchive.fsPath);
+        }
+      }
+    }),
+  );
+
+  ctx.subscriptions.push(
+    // When a file system archive is removed from the workspace, we should
+    // also remove it from our cache.
+    workspace.onDidChangeWorkspaceFolders((event) => {
+      for (const removed of event.removed) {
+        const zipPath = removed.uri.fsPath;
+        afsp.flushCache(zipPath);
+      }
+    }),
+  );
+
+  ctx.subscriptions.push(
+    workspace.registerFileSystemProvider(zipArchiveScheme, afsp, {
+      isCaseSensitive: true,
+      isReadonly: true,
+    }),
   );
 }

extensions/ql-vscode/src/databases/local-databases-ui.ts

@@ -109,9 +109,8 @@ class DatabaseTreeDataProvider
     // Note that events from the database manager are instances of DatabaseChangedEvent
     // and events fired by the UI are instances of DatabaseItem
 
-    // When event.item is undefined, then the entire tree is refreshed.
-    // When event.item is a db item, then only that item is refreshed.
-    this._onDidChangeTreeData.fire(event.item);
+    // When a full refresh has occurred, then all items are refreshed by passing undefined.
+    this._onDidChangeTreeData.fire(event.fullRefresh ? undefined : event.item);
   }
 
   private handleDidChangeCurrentDatabaseItem(

extensions/ql-vscode/src/databases/local-databases/database-events.ts

@@ -16,4 +16,8 @@ export enum DatabaseEventKind {
 export interface DatabaseChangedEvent {
   kind: DatabaseEventKind;
   item: DatabaseItem | undefined;
+  // If true, event handlers should consider the database manager
+  // to have been fully refreshed. Any state managed by the
+  /// event handler shouuld be fully refreshed as well.
+  fullRefresh: boolean;
 }

extensions/ql-vscode/src/databases/local-databases/database-manager.ts

@@ -613,6 +613,7 @@ export class DatabaseManager extends DisposableObject {
       this._onDidChangeCurrentDatabaseItem.fire({
         item,
         kind: DatabaseEventKind.Change,
+        fullRefresh: false,
       });
     }
   }
@@ -662,8 +663,9 @@ export class DatabaseManager extends DisposableObject {
     }
     // note that we use undefined as the item in order to reset the entire tree
     this._onDidChangeDatabaseItem.fire({
-      item: undefined,
+      item,
       kind: DatabaseEventKind.Add,
+      fullRefresh: true,
     });
   }
 
@@ -671,9 +673,9 @@ export class DatabaseManager extends DisposableObject {
     item.name = newName;
     await this.updatePersistedDatabaseList();
     this._onDidChangeDatabaseItem.fire({
-      // pass undefined so that the entire tree is rebuilt in order to re-sort
-      item: undefined,
+      item,
       kind: DatabaseEventKind.Rename,
+      fullRefresh: true,
     });
   }
 
@@ -722,8 +724,9 @@ export class DatabaseManager extends DisposableObject {
 
     // note that we use undefined as the item in order to reset the entire tree
     this._onDidChangeDatabaseItem.fire({
-      item: undefined,
+      item,
       kind: DatabaseEventKind.Remove,
+      fullRefresh: true,
     });
   }
 
@@ -776,6 +779,7 @@ export class DatabaseManager extends DisposableObject {
       this._onDidChangeDatabaseItem.fire({
         kind: DatabaseEventKind.Refresh,
         item: databaseItem,
+        fullRefresh: false,
       });
     }
   }

extensions/ql-vscode/src/extension.ts

@@ -947,7 +947,7 @@ async function activateWithInstalledDistribution(
   ctx.subscriptions.push(compareView);
 
   void extLogger.log("Initializing source archive filesystem provider.");
-  archiveFilesystemProvider_activate(ctx);
+  archiveFilesystemProvider_activate(ctx, dbm);
 
   const qhelpTmpDir = dirSync({
     prefix: "qhelp_",