Add edit command to open session files in $EDITOR

src/cli.ts

@@ -18,6 +18,7 @@ import { action as diffAction } from "./commands/diff.ts"
 import { action as showAction } from "./commands/show.ts"
 import { action as logAction } from "./commands/log.ts"
 import { action as dirAction } from "./commands/dir.ts"
+import { action as editAction } from "./commands/edit.ts"
 import { action as cleanupAction } from "./commands/cleanup.ts"
 import { register as registerVmCommands } from "./commands/vm.ts"
 import { action as completionsAction } from "./commands/completions.ts"
@@ -139,6 +140,13 @@ program
   .description("Open a shell in the VM")
   .action(shellAction)
 
+program
+  .command("edit")
+  .argument("<branch>", "branch name")
+  .argument("<file>", "file path relative to worktree root")
+  .description("Open a file from a session in $EDITOR")
+  .action(editAction)
+
 program
   .command("dir")
   .argument("<branch>", "branch name")

src/commands/edit.ts

@@ -0,0 +1,35 @@
+import { resolve } from "path"
+import { existsSync } from "fs"
+import { die } from "../fmt.ts"
+import { requireSession } from "./helpers.ts"
+
+export async function action(branch: string, file: string) {
+  const editor = process.env.EDITOR
+  if (!editor) {
+    die("$EDITOR is not set.")
+  }
+
+  const { session } = await requireSession(branch)
+  const worktree = resolve(session.worktree)
+  const path = resolve(worktree, file)
+
+  if (!path.startsWith(worktree + "/") && path !== worktree) {
+    die("File path escapes the worktree.")
+  }
+
+  if (!existsSync(path)) {
+    die(`File not found: ${file}`)
+  }
+
+  const [cmd, ...args] = editor.split(/\s+/)
+  const proc = Bun.spawn([cmd, ...args, path], {
+    stdin: "inherit",
+    stdout: "inherit",
+    stderr: "inherit",
+  })
+
+  const exitCode = await proc.exited
+  if (exitCode !== 0) {
+    die(`Editor exited with code ${exitCode}.`)
+  }
+}