Fix issues with PATH override on Windows due to casing

Author: pimterry

src/interceptors/terminal/fresh-terminal-interceptor.ts

@@ -379,12 +379,21 @@ export class TerminalInterceptor implements Interceptor {
         // This gets reset on exit, and is behind a flag so it won't affect other shells anyway.
         if (!skipStartupScripts) await editShellStartupScripts();
 
+
+        const currentEnv = (process.platform === 'win32')
+            // Windows env var behaviour is very odd. Windows env vars are case-insensitive, and node
+            // simulates this for process.env accesses, but when used in an object they become
+            // case-*sensitive* object keys, and it's easy to end up with duplicates.
+            // To fix this, on Windows we enforce here that all env var input keys are uppercase.
+            ? _.mapKeys(process.env, (_value, key) => key.toUpperCase())
+            : process.env;
+
         const childProc = spawn(
             command,
             (args || []),
             _.assign(options || {}, {
-                env: _.assign({}, process.env, getTerminalEnvVars(proxyPort, this.config.https)),
-                cwd: process.env.HOME || process.env.USERPROFILE
+                env: _.assign({}, currentEnv, getTerminalEnvVars(proxyPort, this.config.https, currentEnv)),
+                cwd: currentEnv.HOME || currentEnv.USERPROFILE
             })
         );
 

src/interceptors/terminal/terminal-env-overrides.ts

@@ -12,7 +12,8 @@ export const OVERRIDE_BIN_PATH = path.join(OVERRIDES_DIR, 'path');
 
 export function getTerminalEnvVars(
     proxyPort: number,
-    httpsConfig: HttpsPathOptions
+    httpsConfig: HttpsPathOptions,
+    currentEnv: { [key: string]: string | undefined }
 ): { [key: string]: string } {
     return {
         'http_proxy': `http://localhost:${proxyPort}`,
@@ -44,16 +45,16 @@ export function getTerminalEnvVars(
         'HTTP_TOOLKIT_ACTIVE': 'true',
 
         // Prepend our bin overrides into $PATH
-        'PATH': `${OVERRIDE_BIN_PATH}${PATH_VAR_SEPARATOR}${process.env.PATH}`,
+        'PATH': `${OVERRIDE_BIN_PATH}${PATH_VAR_SEPARATOR}${currentEnv.PATH}`,
 
         // Prepend our Ruby gem overrides into $LOAD_PATH
-        'RUBYLIB': process.env.RUBYLIB
-            ? `${OVERRIDE_RUBYGEMS_PATH}:${process.env.RUBYLIB}`
+        'RUBYLIB': currentEnv.RUBYLIB
+            ? `${OVERRIDE_RUBYGEMS_PATH}:${currentEnv.RUBYLIB}`
             : OVERRIDE_RUBYGEMS_PATH,
 
         // Prepend our Python package overrides into $PYTHONPATH
-        'PYTHONPATH': process.env.PYTHONPATH
-            ? `${OVERRIDE_PYTHONPATH}:${process.env.PYTHONPATH}`
+        'PYTHONPATH': currentEnv.PYTHONPATH
+            ? `${OVERRIDE_PYTHONPATH}:${currentEnv.PYTHONPATH}`
             : OVERRIDE_PYTHONPATH
     };
 }

test/interceptors/fresh-terminal.spec.ts

@@ -48,7 +48,7 @@ describe('Terminal interceptor', function () {
             const stripeRule = await server.get('https://api.stripe.com/v1/customers').thenJson(200, {});
 
             // Spawn node, as if it was run inside an intercepted terminal
-            const terminalEnvOverrides = getTerminalEnvVars(server.port, httpsConfig);
+            const terminalEnvOverrides = getTerminalEnvVars(server.port, httpsConfig, process.env);
             const nodeScript = fork(require.resolve('./fresh-terminal-js-script'), [], {
                 execArgv: ['-r', require.resolve('../../overrides/path/prepend.js')],
                 env: Object.assign({}, process.env, terminalEnvOverrides)