fix quoting for runInBackground (#849)

fixes microsoft/vscode-python#25448

Author: eleanorjboyd

src/features/execution/runInBackground.ts

@@ -12,11 +12,32 @@ export async function runInBackground(
         traceWarn('No Python executable found in environment; falling back to "python".');
         executable = 'python';
     }
-    // Check and quote the executable path if necessary
-    executable = quoteStringIfNecessary(executable);
+
+    // Don't quote the executable path for spawn - it handles spaces correctly on its own
+    // Remove any existing quotes that might cause issues
+    // see https://github.com/nodejs/node/issues/7367 for more details on cp.spawn and quoting
+    if (executable.startsWith('"') && executable.endsWith('"')) {
+        executable = executable.substring(1, executable.length - 1);
+    }
+
     const args = environment.execInfo?.activatedRun?.args ?? environment.execInfo?.run.args ?? [];
     const allArgs = [...args, ...options.args];
-    traceInfo(`Running in background: ${executable} ${allArgs.join(' ')}`);
+
+    // Log the command for debugging
+    traceInfo(`Running in background: "${executable}" ${allArgs.join(' ')}`);
+
+    // Check if the file exists before trying to spawn it
+    try {
+        const fs = require('fs');
+        if (!fs.existsSync(executable)) {
+            traceError(
+                `Python executable does not exist: ${executable}. Attempting to quote the path as a workaround...`,
+            );
+            executable = quoteStringIfNecessary(executable);
+        }
+    } catch (err) {
+        traceWarn(`Error checking if executable exists: ${err instanceof Error ? err.message : String(err)}`);
+    }
 
     const proc = cp.spawn(executable, allArgs, { stdio: 'pipe', cwd: options.cwd, env: options.env });