Make Home/End jump to a selected branch's first and last changesets

src/renderer/src/components/graph/GraphCanvas.tsx

@@ -9,6 +9,7 @@ import { stripCoAuthorTrailers } from '@/lib/coauthors'
 import { reflowMessage } from '@/lib/reflow'
 import { subscribeAvatars } from './avatars'
 import {
+  branchEndpoint,
   captionAlpha,
   captionCenterOffset,
   contentSize,
@@ -819,13 +820,24 @@ export function GraphCanvas({
     }
     if (e.key === 'Home' || e.key === 'End') {
       e.preventDefault()
+      const edge = e.key === 'Home' ? 'first' : 'last'
       const current = s.selectedHash ? s.layout.nodeByHash.get(s.selectedHash) : null
+      const branchRow = current
+        ? null
+        : s.layout.rows.find((r) => rowMatchesSelection(r, s.selectedBranch))
       if (current) {
         // Within the selected commit's branch: Home → its oldest commit,
         // End → its newest.
-        const target = rowEndpoint(s.layout, current, e.key === 'Home' ? 'first' : 'last')
+        const target = rowEndpoint(s.layout, current, edge)
         onSelectNode(target)
         reveal(target.commit.hash)
+      } else if (branchRow) {
+        // A branch is selected: same edges, walked from its own chain.
+        const target = branchEndpoint(s.layout, branchRow, edge)
+        if (target) {
+          onSelectNode(target)
+          reveal(target.commit.hash)
+        }
       } else if (e.key === 'Home') {
         // Nothing selected: Home keeps its classic meaning — frame the
         // home changeset.

src/renderer/src/components/graph/geometry.test.ts

@@ -1,6 +1,7 @@
 import { describe, expect, test } from 'bun:test'
 import type { Commit } from '@shared/types'
 import {
+  branchEndpoint,
   CAPSULE_HALF_H,
   CAPTION_FULL_ZOOM,
   CAPTION_GAP_WORLD,
@@ -231,6 +232,43 @@ describe('graph geometry', () => {
     expect(f1.row).toBe(g2.row)
     expect(rowEndpoint(layout, g2, 'first').commit.hash).toBe('g1')
     expect(rowEndpoint(layout, f1, 'last').commit.hash).toBe('f2')
+
+    // The branch-selected targets walk the same edges from the row itself,
+    // and a lane shared by two chains never leaks into the neighbor.
+    const feat1 = layout.rows.find((r) => r.name === 'feat1')
+    const feat2 = layout.rows.find((r) => r.name === 'feat2')
+    if (!feat1 || !feat2) throw new Error('missing row')
+    expect(branchEndpoint(layout, feat1, 'first')?.commit.hash).toBe('f1')
+    expect(branchEndpoint(layout, feat1, 'last')?.commit.hash).toBe('f2')
+    expect(branchEndpoint(layout, feat2, 'first')?.commit.hash).toBe('g1')
+    expect(branchEndpoint(layout, feat2, 'last')?.commit.hash).toBe('g2')
+  })
+
+  test('Home/End targets when the branch is selected: its oldest and newest commit', () => {
+    const layout = sampleLayout()
+    const main = layout.rows.find((r) => r.name === 'main')
+    const feature = layout.rows.find((r) => r.name === 'feature')
+    if (!main || !feature) throw new Error('missing row')
+    expect(branchEndpoint(layout, main, 'first')?.commit.hash).toBe('a')
+    expect(branchEndpoint(layout, main, 'last')?.commit.hash).toBe('m')
+    // A single-commit branch: both edges are that commit.
+    expect(branchEndpoint(layout, feature, 'first')?.commit.hash).toBe('f')
+    expect(branchEndpoint(layout, feature, 'last')?.commit.hash).toBe('f')
+  })
+
+  test('an empty branch resolves both Home/End edges to its anchor commit', () => {
+    // 'fresh' points at the HEAD tip: zero commits of its own.
+    const layout = layoutGraph({
+      commits: [commit('b', ['a'], 'HEAD -> main, fresh'), commit('a', [])],
+      remotes: [],
+      headBranch: 'main',
+      detached: false,
+      defaultBranch: 'main'
+    })
+    const fresh = layout.rows.find((r) => r.name === 'fresh')
+    if (!fresh) throw new Error('missing empty row')
+    expect(branchEndpoint(layout, fresh, 'first')?.commit.hash).toBe('b')
+    expect(branchEndpoint(layout, fresh, 'last')?.commit.hash).toBe('b')
   })
 
   describe('revealRowDy — keep the clicked row clear of the diff pane', () => {

src/renderer/src/components/graph/geometry.ts

@@ -297,6 +297,24 @@ export function rowEndpoint(
   return best
 }
 
+/** The oldest ('first') or newest ('last') commit of a BRANCH row — the
+ *  Home/End keyboard targets when the branch itself is selected. Walks the
+ *  row's own chain, so a lane shared with another chain never leaks in. An
+ *  empty branch owns no commits; both edges resolve to its anchor commit
+ *  (the tip it points at). */
+export function branchEndpoint(
+  layout: GraphLayout,
+  row: GraphRow,
+  edge: 'first' | 'last'
+): GraphNode | null {
+  let best: GraphNode | null = null
+  for (const n of layout.nodes) {
+    if (n.chain !== row.chain) continue
+    if (!best || (edge === 'first' ? n.column < best.column : n.column > best.column)) best = n
+  }
+  return best ?? layout.nodeByHash.get(row.tipHash) ?? null
+}
+
 /**
  * Keyboard navigation target from `node`: left/right walk the same row (older/
  * newer), up/down jump to the column-nearest node one row away.