fix(proxy): degrade to default dispatcher when proxy agent init fails instead of crashing startup

Author: Andy00L

src/lib/proxy.test.ts

@@ -31,4 +31,29 @@ describe('maybeInstallProxyAgent', () => {
     expect(maybeInstallProxyAgent({ env: { HTTPS_PROXY: '' }, install })).toBe(false);
     expect(install).not.toHaveBeenCalled();
   });
+
+  it('falls back (returns false, warns, never throws) when installing the agent fails', () => {
+    // A malformed/unsupported proxy value makes the agent throw at startup; the
+    // CLI must degrade to a proxy-less dispatcher, not crash every command.
+    const errs: string[] = [];
+    const installed = maybeInstallProxyAgent({
+      env: { HTTPS_PROXY: 'http://proxy.corp.example.com:8080' },
+      install: () => {
+        throw new Error('unsupported proxy scheme');
+      },
+      stderr: line => errs.push(line),
+    });
+    expect(installed).toBe(false);
+    expect(errs.join('\n')).toContain('ignoring proxy environment');
+  });
+
+  it('still installs when NO_PROXY is set (exemptions are applied per request by undici)', () => {
+    const install = vi.fn();
+    const installed = maybeInstallProxyAgent({
+      env: { HTTPS_PROXY: 'http://proxy.corp.example.com:8080', NO_PROXY: 'localhost,127.0.0.1' },
+      install,
+    });
+    expect(installed).toBe(true);
+    expect(install).toHaveBeenCalledTimes(1);
+  });
 });

src/lib/proxy.ts

@@ -20,6 +20,8 @@ export interface ProxyDeps {
   env?: NodeJS.ProcessEnv;
   /** Dispatcher installer. Defaults to undici's setGlobalDispatcher. */
   install?: (agent: Dispatcher) => void;
+  /** Warning sink. Defaults to `process.stderr`. */
+  stderr?: (line: string) => void;
 }
 
 /**
@@ -36,6 +38,21 @@ export function maybeInstallProxyAgent(deps: ProxyDeps = {}): boolean {
   const install = deps.install ?? setGlobalDispatcher;
   // EnvHttpProxyAgent reads HTTPS_PROXY/HTTP_PROXY/NO_PROXY itself, per
   // request, so NO_PROXY exemptions apply without extra plumbing here.
-  install(new EnvHttpProxyAgent());
-  return true;
+  //
+  // A malformed or unsupported proxy value (e.g. `socks5://...`) makes the
+  // agent throw. Because this runs at startup, an unguarded throw would abort
+  // every command before the CLI's own error handling — so fall back to the
+  // default (proxy-less) dispatcher and warn instead of crashing.
+  try {
+    install(new EnvHttpProxyAgent());
+    return true;
+  } catch (error) {
+    const stderr = deps.stderr ?? ((line: string) => process.stderr.write(`${line}\n`));
+    stderr(
+      `warning: ignoring proxy environment (could not initialize proxy agent): ${
+        error instanceof Error ? error.message : String(error)
+      }`,
+    );
+    return false;
+  }
 }