Fix truncated stdout when piping more than 64kb

.changeset/polite-gifts-judge.md

@@ -0,0 +1,5 @@
+---
+"@arethetypeswrong/cli": patch
+---
+
+Fix truncated stdout when piping more than 64kb to another process

packages/cli/src/index.ts

@@ -16,6 +16,8 @@ import * as render from "./render/index.js";
 import { major, minor } from "semver";
 import { getExitCode } from "./getExitCode.js";
 import { applyProfile, profiles } from "./profiles.js";
+import { write } from "./write.js";
+import { Writable } from "stream";
 
 const packageJson = createRequire(import.meta.url)("../package.json");
 const version = packageJson.version;
@@ -98,8 +100,13 @@ particularly ESM-related module resolution issues.`,
       applyProfile(opts.profile, opts);
     }
 
+    let out: Writable = process.stdout;
     if (opts.quiet) {
-      console.log = () => {};
+      out = new (class extends Writable {
+        _write(_chunk: any, _encoding: BufferEncoding, callback: (error?: Error | null) => void) {
+          callback();
+        }
+      })();
     }
 
     if (!opts.color) {
@@ -223,7 +230,7 @@ particularly ESM-related module resolution issues.`,
         result.problems = groupProblemsByKind(analysis.problems);
       }
 
-      console.log(JSON.stringify(result, undefined, 2));
+      await write(JSON.stringify(result, undefined, 2), out);
 
       if (deleteTgz) {
         await unlink(deleteTgz);
@@ -237,12 +244,12 @@ particularly ESM-related module resolution issues.`,
       return;
     }
 
-    console.log();
+    await write("", out);
     if (analysis.types) {
-      console.log(await render.typed(analysis, opts));
+      await write(await render.typed(analysis, opts), out);
       process.exitCode = getExitCode(analysis, opts);
     } else {
-      console.log(render.untyped(analysis as core.UntypedResult));
+      await write(render.untyped(analysis as core.UntypedResult), out);
     }
 
     if (deleteTgz) {

packages/cli/src/write.ts

@@ -0,0 +1,27 @@
+import { Readable, Writable } from "node:stream";
+
+// JSON output is often longer than 64 kb, so we need to use streams to write it to stdout
+// in order to avoid truncation when piping to other commands.
+export async function write(data: string, out: Writable): Promise<void> {
+  return new Promise((resolve, reject) => {
+    const stream = new Readable({
+      read() {
+        this.push(data);
+        this.push("\n");
+        this.push(null);
+      },
+    });
+
+    stream.on("data", (chunk) => {
+      out.write(chunk);
+    });
+
+    stream.on("end", () => {
+      resolve();
+    });
+
+    out.on("error", (err) => {
+      reject(err);
+    });
+  });
+}

packages/cli/test/snapshots.test.ts

@@ -1,5 +1,5 @@
+import { execFileSync, type SpawnSyncReturns } from "child_process";
 import { access, readFile, writeFile } from "fs/promises";
-import { execSync, type SpawnSyncReturns } from "child_process";
 import assert from "node:assert";
 import path from "node:path";
 import { after, describe, test } from "node:test";
@@ -10,7 +10,7 @@ function resolveFileRelativePath(relPath: string) {
   return path.resolve(directoryPath, relPath);
 }
 
-const attw = `node ${resolveFileRelativePath("../../dist/index.js")}`;
+const attw = resolveFileRelativePath("../../dist/index.js");
 const updateSnapshots = process.env.UPDATE_SNAPSHOTS || process.env.U;
 const testFilter = (process.env.TEST_FILTER || process.env.T)?.toLowerCase();
 
@@ -91,7 +91,8 @@ describe("snapshots", async () => {
       let stderr = "";
       let exitCode = 0;
       try {
-        stdout = execSync(`${attw} ${tarballPath} ${options ?? defaultOpts}`, {
+        stdout = execFileSync(process.execPath, [attw, tarballPath, ...(options ?? defaultOpts).split(" ")], {
+          maxBuffer: 1024 * 1024 * 1024,
           encoding: "utf8",
           env: { ...process.env, FORCE_COLOR: "0" },
         });