From 045eabbbf95344cf29963eaf5b73fc5beb63b54d Mon Sep 17 00:00:00 2001
From: David Kay <dkay@fastmail.com>
Date: Fri, 20 Mar 2026 23:05:15 -0500
Subject: [PATCH] fix: use fs.writeSync for stdout to prevent pipe truncation

process.stdout.write() is async when stdout is a pipe. The
immediate process.exit(0) tears down the process before the
downstream reader (jq, python3, etc) consumes the buffer,
producing truncated JSON.

Replace with fs.writeSync(1, data) which blocks until the
kernel pipe buffer accepts the bytes, and drop process.exit(0)
on the success path so the event loop drains naturally.

Fixes #1275
Related: #493 (addressed >50KB case, this fixes <50KB)
---
 get-shit-done/bin/lib/core.cjs | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/get-shit-done/bin/lib/core.cjs b/get-shit-done/bin/lib/core.cjs
index a068d9ac6..1fba6f877 100644
--- a/get-shit-done/bin/lib/core.cjs
+++ b/get-shit-done/bin/lib/core.cjs
@@ -147,8 +147,9 @@ function reapStaleTempFiles(prefix = 'gsd-', { maxAgeMs = 5 * 60 * 1000, dirsOnl
 }
 
 function output(result, raw, rawValue) {
+  let data;
   if (raw && rawValue !== undefined) {
-    process.stdout.write(String(rawValue));
+    data = String(rawValue);
   } else {
     const json = JSON.stringify(result, null, 2);
     // Large payloads exceed Claude Code's Bash tool buffer (~50KB).
@@ -157,16 +158,20 @@ function output(result, raw, rawValue) {
       reapStaleTempFiles();
       const tmpPath = path.join(require('os').tmpdir(), `gsd-${Date.now()}.json`);
       fs.writeFileSync(tmpPath, json, 'utf-8');
-      process.stdout.write('@file:' + tmpPath);
+      data = '@file:' + tmpPath;
     } else {
-      process.stdout.write(json);
+      data = json;
     }
   }
-  process.exit(0);
+  // process.stdout.write() is async when stdout is a pipe — process.exit()
+  // can tear down the process before the reader consumes the buffer.
+  // fs.writeSync(1, ...) blocks until the kernel accepts the bytes, and
+  // skipping process.exit() lets the event loop drain naturally.
+  fs.writeSync(1, data);
 }
 
 function error(message) {
-  process.stderr.write('Error: ' + message + '\n');
+  fs.writeSync(2, 'Error: ' + message + '\n');
   process.exit(1);
 }