From 376f918a66dce5094bc0e2fc9043f870b44b8034 Mon Sep 17 00:00:00 2001
From: Chris Wanstrath <chris@ozmm.org>
Date: Sat, 21 Feb 2026 08:36:44 -0800
Subject: [PATCH] refactor merge: extract lineCount helper, hoist preamble, and
 gracefully handle git errors

---
 src/commands/merge.ts | 43 +++++++++++++++++++++++++------------------
 src/git.ts            | 12 ++++--------
 2 files changed, 29 insertions(+), 26 deletions(-)

diff --git a/src/commands/merge.ts b/src/commands/merge.ts
index 26408e5..00f7ace 100644
--- a/src/commands/merge.ts
+++ b/src/commands/merge.ts
@@ -8,10 +8,15 @@ import { action as closeAction } from "./close.ts"
 
 const MAX_DIFF_LINES = 300
 
-function truncate(text: string, maxLines = 200): string {
-  const lines = text.split("\n")
-  if (lines.length <= maxLines) return text
-  return lines.slice(0, maxLines).join("\n") + `\n... (truncated, ${lines.length - maxLines} more lines)`
+function lineCount(text: string): number {
+  if (!text) return 0
+  return text.split("\n").length
+}
+
+function truncate(text: string, maxLines = MAX_DIFF_LINES): string {
+  const count = lineCount(text)
+  if (count <= maxLines) return text
+  return text.split("\n").slice(0, maxLines).join("\n") + `\n... (truncated, ${count - maxLines} more lines)`
 }
 
 export async function action(branch: string) {
@@ -59,9 +64,7 @@ export async function action(branch: string) {
     const resolvable: typeof fileDiffs = []
     const skipped: string[] = []
     for (const entry of fileDiffs) {
-      const oursLines = entry.oursDiff ? entry.oursDiff.split("\n").length : 0
-      const theirsLines = entry.theirsDiff ? entry.theirsDiff.split("\n").length : 0
-      if (oursLines > MAX_DIFF_LINES || theirsLines > MAX_DIFF_LINES) {
+      if (lineCount(entry.oursDiff) > MAX_DIFF_LINES || lineCount(entry.theirsDiff) > MAX_DIFF_LINES) {
         skipped.push(entry.file)
       } else {
         resolvable.push(entry)
@@ -69,27 +72,31 @@ export async function action(branch: string) {
     }
 
     if (resolvable.length === 0) {
-      await git.abortMerge(root)
       spin.fail("All conflicts are too complex for auto-resolution")
       console.log("\nThe following files need manual resolution:")
       for (const file of skipped) console.log(`  - ${file}`)
-      process.exit(1)
+      console.log("\nResolve them manually, then run: git add <files> && git commit --no-edit")
+      return
     }
 
+    const preamble = [
+      `## Merge Context`,
+      `Merging branch \`${branch}\` into \`${current}\``,
+      ``,
+      `### Commits on \`${branch}\`:`,
+      (branchLog && truncate(branchLog, 50)) || "(no commits)",
+      ``,
+      `### Overall changes on \`${branch}\`:`,
+      (branchDiffStat && truncate(branchDiffStat, 100)) || "(no changes)",
+    ].join("\n")
+
     for (const { file, oursDiff, theirsDiff } of resolvable) {
       spin.text = `Resolving ${file}`
 
       const content = await Bun.file(join(root, file)).text()
 
       const context = [
-        `## Merge Context`,
-        `Merging branch \`${branch}\` into \`${current}\``,
-        ``,
-        `### Commits on \`${branch}\`:`,
-        (branchLog && truncate(branchLog, 50)) || "(no commits)",
-        ``,
-        `### Overall changes on \`${branch}\`:`,
-        (branchDiffStat && truncate(branchDiffStat, 100)) || "(no changes)",
+        preamble,
         ``,
         `---`,
         `## Conflicted File: ${file}`,
@@ -121,7 +128,7 @@ export async function action(branch: string) {
       spin.succeed(`Resolved ${resolvable.length} of ${conflicts.length} conflict(s)`)
       console.log("\nThe following files are too complex for auto-resolution:")
       for (const file of skipped) console.log(`  - ${file}`)
-      console.log("\nResolve them manually, then run: git commit --no-edit")
+      console.log("\nResolve them manually, then run: git add <files> && git commit --no-edit")
       return
     }
 
diff --git a/src/git.ts b/src/git.ts
index 700a265..faee459 100644
--- a/src/git.ts
+++ b/src/git.ts
@@ -135,21 +135,17 @@ export async function mergeBase(ref1: string, ref2: string, cwd: string): Promis
   return result.text().trim()
 }
 
-/** Get a one-line-per-commit log for a revision range. */
+/** Get a one-line-per-commit log for a revision range. Returns empty string on failure. */
 export async function commitLog(range: string, cwd: string): Promise<string> {
   const result = await $`git log --oneline ${range}`.cwd(cwd).nothrow().quiet()
-  if (result.exitCode !== 0) {
-    throw new Error(`Failed to get log for range "${range}"`)
-  }
+  if (result.exitCode !== 0) return ""
   return result.text().trim()
 }
 
-/** Get a diff stat summary for a revision range. */
+/** Get a diff stat summary for a revision range. Returns empty string on failure. */
 export async function diffStat(range: string, cwd: string): Promise<string> {
   const result = await $`git diff --stat ${range}`.cwd(cwd).nothrow().quiet()
-  if (result.exitCode !== 0) {
-    throw new Error(`Failed to get diff stat for range "${range}"`)
-  }
+  if (result.exitCode !== 0) return ""
   return result.text().trim()
 }