feat: better windows support

Author: saltenasl

DEEPNOTE_KERNEL_IMPLEMENTATION.md

@@ -43,9 +43,9 @@ This implementation adds automatic kernel selection and startup for `.deepnote`
 - Finds an available port (starting from 8888)
 - Starts the server with `python -m deepnote_toolkit server --jupyter-port <port>`
 - **Sets environment variables** so shell commands use the venv's Python:
-  - Prepends venv's bin directory to `PATH`
-  - Sets `VIRTUAL_ENV` to the venv path
-  - Removes `PYTHONHOME` to avoid conflicts
+  - Prepends venv's bin directory to `PATH` (POSIX: `<venv>/bin`, Windows: `<venv>\Scripts`)
+  - Sets `VIRTUAL_ENV` to the venv path (both platforms)
+  - Removes `PYTHONHOME` to avoid conflicts (both platforms)
 - Monitors server output and logs it
 - Waits for server to be ready before returning connection info
 - Reuses existing server for the same `.deepnote` file if already running
@@ -383,9 +383,9 @@ These changes ensure that Deepnote notebooks can execute cells reliably by:
 
 2. **Environment variable configuration** (ensures shell commands use venv Python):
    - When starting the Jupyter server, set environment variables:
-     - Prepend venv's `bin/` directory to `PATH`
-     - Set `VIRTUAL_ENV` to point to the venv
-     - Remove `PYTHONHOME` (can interfere with venv)
+     - Prepend venv's bin directory to `PATH` (POSIX: `<venv>/bin`, Windows: `<venv>\Scripts`)
+     - Set `VIRTUAL_ENV` to point to the venv (both platforms)
+     - Remove `PYTHONHOME` (can interfere with venv, both platforms)
    - This ensures `!pip install` and other shell commands use the venv's Python
 
 **Result**: Both the kernel and shell commands now use the same Python environment (the venv), so packages installed via `!pip install` or `%pip install` are immediately available for import.

src/kernels/deepnote/deepnoteServerStarter.node.ts

@@ -99,17 +99,32 @@ export class DeepnoteServerStarter implements IDeepnoteServerStarter {
         const processService = await this.processServiceFactory.create(interpreter.uri);
 
         // Set up environment to ensure the venv's Python is used for shell commands
-        const venvBinDir = interpreter.uri.fsPath.replace(/\/python$/, '').replace(/\\python\.exe$/, '');
         const env = { ...process.env };
 
+        // Get the virtual environment directory from the Python interpreter path
+        const interpreterPath = interpreter.uri.fsPath;
+        let venvPath: string;
+        let venvBinDir: string;
+
+        if (process.platform === 'win32') {
+            // Windows: Python executable is typically in <venv>\Scripts\python.exe
+            // Extract venv path by removing \Scripts\python.exe
+            venvPath = interpreterPath.replace(/[\\/]Scripts[\\/]python\.exe$/i, '');
+            venvBinDir = interpreterPath.replace(/[\\/]python\.exe$/i, '');
+        } else {
+            // POSIX: Python executable is typically in <venv>/bin/python
+            // Extract venv path by removing /bin/python
+            venvPath = interpreterPath.replace(/\/bin\/python$/, '');
+            venvBinDir = interpreterPath.replace(/\/python$/, '');
+        }
+
         // Prepend venv bin directory to PATH so shell commands use venv's Python
         env.PATH = `${venvBinDir}${process.platform === 'win32' ? ';' : ':'}${env.PATH || ''}`;
 
-        // Also set VIRTUAL_ENV to indicate we're in a venv
-        const venvPath = venvBinDir.replace(/\/bin$/, '').replace(/\\Scripts$/, '');
+        // Set VIRTUAL_ENV to indicate we're in a venv (both platforms)
         env.VIRTUAL_ENV = venvPath;
 
-        // Remove PYTHONHOME if it exists (can interfere with venv)
+        // Remove PYTHONHOME if it exists (can interfere with venv, both platforms)
         delete env.PYTHONHOME;
 
         // Get the directory containing the notebook file to set as working directory