Fix for issue microsoft#11396

* During notebook cell debugging, apply path normalization on the path of the dumped tmp file only if the kernel runs on a Windows machine.

news/2 Fixes/11396.md

@@ -0,0 +1,2 @@
+Fixed a bug that introduced a cross-OS interworking issue, making the notebook cell debugger skip breakpoints when VSCode is run on Windows but the kernel is run on Unix
+(thanks [Adam Zlatniczki](https://github.com/adam-zlatniczki))

src/interactive-window/debugger/jupyter/kernelDebugAdapter.ts

@@ -90,7 +90,7 @@ export class KernelDebugAdapter extends KernelDebugAdapterBase {
             const response = await this.session.customRequest('dumpCell', { code });
 
             // We know jupyter will strip out leading white spaces, hence take that into account.
-            const norm = path.normalize((response as IDumpCellResponse).sourcePath);
+            const norm = KernelDebugAdapterBase.extractDumpFilePathOnKernelSide(response as IDumpCellResponse);
             this.fileToCell.set(norm, Uri.parse(metadata.interactive.uristring));
 
             // If this cell doesn't have a cell marker, then
@@ -131,8 +131,10 @@ export class KernelDebugAdapter extends KernelDebugAdapterBase {
         if (!cell) {
             return;
         }
+
         source.name = path.basename(cell.interactiveWindow.path);
-        source.path = cell.interactiveWindow.toString();
+        source.path = cell.interactiveWindow.path;
+
         if (typeof lines?.endLine === 'number') {
             lines.endLine = lines.endLine + (cell.lineOffset || 0);
         }

src/notebooks/debugger/kernelDebugAdapter.ts

@@ -3,11 +3,10 @@
 
 'use strict';
 
-import * as path from '../../platform/vscode-path/path';
-import { IDumpCellResponse } from './debuggingTypes';
 import { traceError } from '../../platform/logging';
 import { KernelDebugAdapterBase } from './kernelDebugAdapterBase';
 import { DebugProtocol } from 'vscode-debugprotocol';
+import { IDumpCellResponse } from './debuggingTypes';
 
 /**
  * Concrete implementation of the KernelDebugAdapterBase class that will dump cells
@@ -22,7 +21,7 @@ export class KernelDebugAdapter extends KernelDebugAdapterBase {
             const response = await this.session.customRequest('dumpCell', {
                 code: cell.document.getText().replace(/\r\n/g, '\n')
             });
-            const norm = path.normalize((response as IDumpCellResponse).sourcePath);
+            const norm = KernelDebugAdapterBase.extractDumpFilePathOnKernelSide(response as IDumpCellResponse);
             this.fileToCell.set(norm, cell.document.uri);
             this.cellToFile.set(cell.document.uri.toString(), norm);
         } catch (err) {

src/notebooks/debugger/kernelDebugAdapterBase.ts

@@ -21,6 +21,7 @@ import {
     Uri,
     workspace
 } from 'vscode';
+import { IDumpCellResponse } from './debuggingTypes';
 import { DebugProtocol } from 'vscode-debugprotocol';
 import { executeSilently } from '../../kernels/helpers';
 import { IKernel, IKernelConnectionSession } from '../../kernels/types';
@@ -264,6 +265,20 @@ export abstract class KernelDebugAdapterBase implements DebugAdapter, IKernelDeb
         });
     }
 
+    static extractDumpFilePathOnKernelSide(dumpCellResponse: IDumpCellResponse) {
+        // Based on the response, check if the kernel runs on a Unix or Windows machine.
+        // If it runs on Windows, then path windows-style normalization might be necessary
+        // (see https://github.com/ipython/ipykernel/issues/995).
+        const dumpFilePathOnKernelSide = dumpCellResponse.sourcePath;
+        let norm = '';
+        if (dumpFilePathOnKernelSide.match(/^[A-Za-z]:/)) {
+            norm = path.win32.normalize(dumpFilePathOnKernelSide);
+        } else {
+            norm = dumpFilePathOnKernelSide;
+        }
+        return norm;
+    }
+
     private lookupCellByLongName(sourcePath: string) {
         if (!this.platformService.isWindows) {
             return undefined;

src/test/debugger/jupyter/kernelDebugAdapter.unit.test.ts

@@ -0,0 +1,28 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+import { expect } from 'chai';
+import { KernelDebugAdapterBase } from '../../../notebooks/debugger/kernelDebugAdapterBase';
+import { IDumpCellResponse } from '../../../notebooks/debugger/debuggingTypes';
+
+suite('Debugging - KernelDebugAdapterBase', () => {
+    suite('extractDumpFilePathOnKernelSide', async () => {
+        test('Kernel runs on Windows backend', () => {
+            const mockResponseFromKernel = { sourcePath: 'c:\\tmp\\1.py' } as IDumpCellResponse;
+            const path = KernelDebugAdapterBase.extractDumpFilePathOnKernelSide(mockResponseFromKernel);
+            expect(path).to.equal('c:\\tmp\\1.py');
+        });
+
+        test('Kernel runs on Windows backend with ipykernel issue', () => {
+            const mockResponseFromKernel = { sourcePath: 'c:\\tmp/1.py' } as IDumpCellResponse;
+            const path = KernelDebugAdapterBase.extractDumpFilePathOnKernelSide(mockResponseFromKernel);
+            expect(path).to.equal('c:\\tmp\\1.py');
+        });
+
+        test('Kernel runs on Unix backend', () => {
+            const mockResponseFromKernel = { sourcePath: '/tmp/1.py' } as IDumpCellResponse;
+            const path = KernelDebugAdapterBase.extractDumpFilePathOnKernelSide(mockResponseFromKernel);
+            expect(path).to.equal('/tmp/1.py');
+        });
+    });
+});