From 4cde0c20863bba65f4316ee5fb60b97cd8e3176a Mon Sep 17 00:00:00 2001
From: Chris Wanstrath <chris@ozmm.org>
Date: Sun, 22 Feb 2026 07:31:30 -0800
Subject: [PATCH] Use inherited stdio for git diff/show to support external
 diff tools and native paging

---
 src/commands/diff.ts | 32 +++++++++++++++-----------------
 src/commands/show.ts | 27 ++++++++++++++-------------
 2 files changed, 29 insertions(+), 30 deletions(-)

diff --git a/src/commands/diff.ts b/src/commands/diff.ts
index b372585..ba03a6e 100644
--- a/src/commands/diff.ts
+++ b/src/commands/diff.ts
@@ -1,6 +1,5 @@
 import { $ } from "bun"
 import * as git from "../git.ts"
-import { pager } from "../fmt.ts"
 import { requireSession } from "./helpers.ts"
 
 export async function action(branch: string) {
@@ -13,27 +12,26 @@ export async function action(branch: string) {
     process.exit(1)
   }
 
-  let diff: string
+  let args: string[]
   if (status.text().trim().length > 0) {
     // Show uncommitted changes (both staged and unstaged)
-    const result = await $`git -C ${session.worktree} diff --color=always HEAD`.nothrow().quiet()
-    if (result.exitCode !== 0) {
-      // HEAD may not exist yet (no commits); fall back to showing all tracked + untracked
-      const fallback = await $`git -C ${session.worktree} diff --color=always`.nothrow().quiet()
-      diff = fallback.text()
-    } else {
-      diff = result.text()
-    }
+    const hasHead = await $`git -C ${session.worktree} rev-parse --verify HEAD`.nothrow().quiet()
+    args = hasHead.exitCode === 0 ? ["diff", "HEAD"] : ["diff"]
   } else {
     // No uncommitted changes — show full branch diff vs main
     const main = await git.mainBranch(session.worktree)
-    const result = await $`git -C ${session.worktree} diff --color=always ${main}...${branch}`.nothrow().quiet()
-    if (result.exitCode !== 0) {
-      console.error("✖ git diff failed")
-      process.exit(1)
-    }
-    diff = result.text()
+    args = ["diff", `${main}...${branch}`]
   }
 
-  await pager(diff)
+  // Run git diff with inherited stdio so external diff tools (e.g. difftastic)
+  // see a real TTY and git can use its own pager
+  const proc = Bun.spawn(["git", "-C", session.worktree, ...args], {
+    stdin: "inherit",
+    stdout: "inherit",
+    stderr: "inherit",
+  })
+  const exitCode = await proc.exited
+  if (exitCode !== 0) {
+    process.exit(exitCode)
+  }
 }
diff --git a/src/commands/show.ts b/src/commands/show.ts
index 68ec167..1d7e7c6 100644
--- a/src/commands/show.ts
+++ b/src/commands/show.ts
@@ -1,23 +1,24 @@
-import { $ } from "bun"
 import * as git from "../git.ts"
-import { pager } from "../fmt.ts"
 import { requireSession } from "./helpers.ts"
 
 export async function action(branch: string) {
   const { session } = await requireSession(branch)
 
-  const main = await git.mainBranch(session.worktree)
-  const result = await $`git -C ${session.worktree} diff --color=always ${main}...${branch}`.nothrow().quiet()
-  if (result.exitCode !== 0) {
-    console.error("git diff failed")
-    process.exit(1)
-  }
-
-  let output = ""
   if (session.prompt) {
-    output += `PROMPT: ${session.prompt}\n\n`
+    process.stderr.write(`PROMPT: ${session.prompt}\n\n`)
   }
-  output += result.text()
 
-  await pager(output)
+  const main = await git.mainBranch(session.worktree)
+
+  // Run git diff with inherited stdio so external diff tools (e.g. difftastic)
+  // see a real TTY and git can use its own pager
+  const proc = Bun.spawn(["git", "-C", session.worktree, "diff", `${main}...${branch}`], {
+    stdin: "inherit",
+    stdout: "inherit",
+    stderr: "inherit",
+  })
+  const exitCode = await proc.exited
+  if (exitCode !== 0) {
+    process.exit(exitCode)
+  }
 }