Refresh non-destructively on save and harden session lifecycle

Author: mguzmanm

src/views/solution-outline/commands/merge-command.test.ts

@@ -83,6 +83,7 @@ describe('MergeCommand', () => {
         mergeSessionCoordinator = {
             activate: jest.fn().mockResolvedValue(),
             startSession: jest.fn(),
+            cancelSession: jest.fn(),
             onMergeProcessExit: jest.fn().mockResolvedValue(),
         };
         command = new MergeCommand(commandsProvider, mergeSessionCoordinator);
@@ -361,6 +362,7 @@ describe('MergeCommand', () => {
             expect(warningSpy).toHaveBeenCalledWith('Merge exited with code 1. Conflicts may exist.');
             expect(mergeSessionCoordinator.startSession).toHaveBeenCalledTimes(1);
             expect(mergeSessionCoordinator.onMergeProcessExit).toHaveBeenCalledWith(1);
+            expect(mergeSessionCoordinator.cancelSession).not.toHaveBeenCalled();
         });
 
         it('handles merge errors gracefully', async () => {
@@ -377,6 +379,7 @@ describe('MergeCommand', () => {
             await command['runVSCodeMerge'](fileNode);
             expect(errorSpy).toHaveBeenCalledWith('Merge operations failed:', expect.any(Error));
             expect(showErrorMessageSpy).toHaveBeenCalledWith('Merge operation failed: unexpected');
+            expect(mergeSessionCoordinator.cancelSession).toHaveBeenCalledTimes(1);
         });
 
         it('shows a merge failure message when merge command validation throws', async () => {
@@ -402,6 +405,7 @@ describe('MergeCommand', () => {
             await command['runVSCodeMerge'](node);
 
             expect(showErrorMessageSpy).toHaveBeenCalledWith('Merge operation failed: Invalid update file: contains unsupported shell-sensitive characters.');
+            expect(mergeSessionCoordinator.cancelSession).toHaveBeenCalledTimes(1);
         });
 
         it('starts merge session and notifies coordinator when merge exits successfully', async () => {
@@ -435,6 +439,7 @@ describe('MergeCommand', () => {
                 mergedMTimeBefore: 1000,
             });
             expect(mergeSessionCoordinator.onMergeProcessExit).toHaveBeenCalledWith(0);
+            expect(mergeSessionCoordinator.cancelSession).not.toHaveBeenCalled();
         });
     });
 });

src/views/solution-outline/commands/merge-command.ts

@@ -108,6 +108,7 @@ export class MergeCommand {
 
         // get the modification time of the merged file before merge
         const mergedMTimeBefore = fsUtils.getFileModificationTime(merged);
+        let exitHandled = false;
 
         try {
             this.mergeSessionCoordinator.startSession({
@@ -120,6 +121,7 @@ export class MergeCommand {
             const command = this.buildMergeCommand(codePath, local, update, base, merged);
             const exitCode = await this.doOpen3WayMerge(command);
             await this.mergeSessionCoordinator.onMergeProcessExit(exitCode);
+            exitHandled = true;
 
             if (exitCode !== 0) {
                 console.warn(`Merge exited with code ${exitCode}. Conflicts may exist.`);
@@ -129,6 +131,10 @@ export class MergeCommand {
             console.error('Merge operations failed:', err);
             const details = err instanceof Error ? err.message : String(err);
             vscode.window.showErrorMessage(`Merge operation failed: ${details}`);
+        } finally {
+            if (!exitHandled) {
+                this.mergeSessionCoordinator.cancelSession();
+            }
         }
     }
 

src/views/solution-outline/commands/merge-session-coordinator.test.ts

@@ -52,7 +52,7 @@ describe('MergeSessionCoordinator', () => {
         testDataHandler.dispose();
     });
 
-    it('finalizes merge on save and refreshes solution', async () => {
+    it('refreshes on save without destructive file operations', async () => {
         const local = path.join(tmpDir, 'component.c');
         const update = path.join(tmpDir, 'component.c.update@1.0.0');
         const base = path.join(tmpDir, 'component.c.base@1.0.0');
@@ -69,12 +69,12 @@ describe('MergeSessionCoordinator', () => {
             handleDidSaveTextDocument: (document: vscode.TextDocument) => Promise<void>
         }).handleDidSaveTextDocument({ uri: { fsPath: merged } } as vscode.TextDocument);
 
-        const newBase = path.join(tmpDir, 'component.c.base@1.0.0');
-        expect(fsUtils.fileExists(`${local}.bak`)).toBeTruthy();
         expect(fsUtils.fileExists(local)).toBeTruthy();
-        expect(fsUtils.readTextFile(local)).toContain('// merged');
-        expect(fsUtils.fileExists(merged)).toBeFalsy();
-        expect(fsUtils.fileExists(newBase)).toBeTruthy();
+        expect(fsUtils.readTextFile(local)).toContain('// local');
+        expect(fsUtils.fileExists(merged)).toBeTruthy();
+        expect(fsUtils.fileExists(base)).toBeTruthy();
+        expect(fsUtils.fileExists(update)).toBeTruthy();
+        expect(fsUtils.fileExists(`${local}.bak`)).toBeFalsy();
 
         expect(solutionManager.refresh).toHaveBeenCalledTimes(1);
     });
@@ -100,6 +100,28 @@ describe('MergeSessionCoordinator', () => {
         expect(fsUtils.fileExists(merged)).toBeTruthy();
     });
 
+    it('does not refresh on save after session is canceled', async () => {
+        const local = path.join(tmpDir, 'component.c');
+        const update = path.join(tmpDir, 'component.c.update@1.0.0');
+        const base = path.join(tmpDir, 'component.c.base@1.0.0');
+        const merged = `${local}.merged`;
+
+        fsUtils.writeTextFile(local, '// local\n');
+        fsUtils.writeTextFile(update, '// update\n');
+        fsUtils.writeTextFile(base, '// base\n');
+        fsUtils.writeTextFile(merged, '// merged\n');
+
+        coordinator.startSession({ local, update, base, merged, mergedMTimeBefore: 0 });
+        coordinator.cancelSession();
+
+        await (coordinator as unknown as {
+            handleDidSaveTextDocument: (document: vscode.TextDocument) => Promise<void>
+        }).handleDidSaveTextDocument({ uri: { fsPath: merged } } as vscode.TextDocument);
+
+        expect(solutionManager.refresh).not.toHaveBeenCalled();
+        expect(fsUtils.fileExists(merged)).toBeTruthy();
+    });
+
     it('finalizes on merge process exit when save hook did not run', async () => {
         const local = path.join(tmpDir, 'component.c');
         const update = path.join(tmpDir, 'component.c.update@1.0.0');

src/views/solution-outline/commands/merge-session-coordinator.ts

@@ -31,6 +31,7 @@ export interface MergeSessionFiles {
 export interface MergeSessionCoordinator {
     activate(context: Pick<vscode.ExtensionContext, 'subscriptions'>): Promise<void>;
     startSession(files: MergeSessionFiles): void;
+    cancelSession(): void;
     onMergeProcessExit(exitCode: number): Promise<void>;
 }
 
@@ -53,11 +54,18 @@ export class MergeSessionCoordinatorImpl implements MergeSessionCoordinator {
         this.activeSession = files;
     }
 
+    public cancelSession(): void {
+        this.activeSession = undefined;
+    }
+
     public async onMergeProcessExit(exitCode: number): Promise<void> {
-        if (exitCode === 0) {
-            await this.tryFinalize();
+        try {
+            if (exitCode === 0) {
+                await this.tryFinalizeOnExit();
+            }
+        } finally {
+            this.activeSession = undefined;
         }
-        this.activeSession = undefined;
     }
 
     private async handleDidSaveTextDocument(document: vscode.TextDocument): Promise<void> {
@@ -67,10 +75,12 @@ export class MergeSessionCoordinatorImpl implements MergeSessionCoordinator {
         if (!pathsEqual(document.uri.fsPath, this.activeSession.merged)) {
             return;
         }
-        await this.tryFinalize();
+        // Keep save handling non-destructive while the merge editor is still open.
+        // The actual file rename/delete operations are performed on merge process exit.
+        await this.solutionManager.refresh();
     }
 
-    private async tryFinalize(): Promise<void> {
+    private async tryFinalizeOnExit(): Promise<void> {
         if (!this.activeSession || this.finalizing) {
             return;
         }