fix: ralpi-plan properly loads task-manager prompt

src/task-manager-prompt.ts

@@ -0,0 +1,104 @@
+import * as fs from "node:fs";
+import * as path from "node:path";
+import { stripFrontmatter } from "@earendil-works/pi-coding-agent";
+
+const TEMPLATE_REL = path.join("prompts", "task-manager.md");
+
+/**
+ * Parse command arguments respecting quoted strings (bash-style).
+ * Ported from pi's core/prompt-templates.js so the task-manager template
+ * receives the same arg-splitting a real `/task-manager` invocation would.
+ */
+function parseCommandArgs(argsString: string): string[] {
+  const args: string[] = [];
+  let current = "";
+  let inQuote: string | null = null;
+  for (let i = 0; i < argsString.length; i++) {
+    const char = argsString[i];
+    if (inQuote) {
+      if (char === inQuote) {
+        inQuote = null;
+      } else {
+        current += char;
+      }
+    } else if (char === '"' || char === "'") {
+      inQuote = char;
+    } else if (/\s/.test(char)) {
+      if (current) {
+        args.push(current);
+        current = "";
+      }
+    } else {
+      current += char;
+    }
+  }
+  if (current) args.push(current);
+  return args;
+}
+
+/**
+ * Substitute argument placeholders in template content.
+ * Faithful port of pi's substituteArgs (core/prompt-templates.js):
+ *   - $1, $2, ...        positional args
+ *   - $@ / $ARGUMENTS    all args joined
+ *   - ${N:-default}      positional N with default when missing/empty
+ *   - ${@:-default}      all args with default when empty
+ *   - ${@:N} / ${@:N:L}  bash-style slicing
+ *
+ * Replacement runs once over the template only; argument/default values
+ * containing patterns like $1 or $@ are NOT recursively substituted.
+ */
+function substituteArgs(content: string, args: string[]): string {
+  const allArgs = args.join(" ");
+  return content.replace(
+    /\$\{(\d+|ARGUMENTS|@):-([^}]*)\}|\$\{@:(\d+)(?::(\d+))?\}|\$(ARGUMENTS|@|\d+)/g,
+    (_match, defaultTarget, defaultValue, sliceStart, sliceLength, simple) => {
+      if (defaultTarget) {
+        const value =
+          defaultTarget === "@" || defaultTarget === "ARGUMENTS"
+            ? allArgs
+            : args[parseInt(defaultTarget, 10) - 1];
+        return value ? value : defaultValue;
+      }
+      if (sliceStart) {
+        let start = parseInt(sliceStart, 10) - 1; // 1-indexed → 0-indexed
+        if (start < 0) start = 0;
+        if (sliceLength) {
+          const length = parseInt(sliceLength, 10);
+          return args.slice(start, start + length).join(" ");
+        }
+        return args.slice(start).join(" ");
+      }
+      if (simple === "ARGUMENTS" || simple === "@") {
+        return allArgs;
+      }
+      const index = parseInt(simple, 10) - 1;
+      return args[index] ?? "";
+    },
+  );
+}
+
+/**
+ * Load and expand the task-manager prompt template bundled with the extension.
+ *
+ * `pi.sendUserMessage()` sends with `expandPromptTemplates: false`, so it will
+ * NOT expand a `/task-manager` invocation — and `@task-manager` is an
+ * @-mention, not a template invocation anyway. We therefore read the
+ * template ourselves, strip its frontmatter, substitute args ($@ etc.), and
+ * return the fully-expanded prompt body ready to send as a user message.
+ *
+ * @param extensionDir  Absolute path to the extension root (where index.ts
+ *                      lives), used to locate `prompts/task-manager.md`.
+ * @param argsString    Raw argument string from the slash command (may be "").
+ * @throws if the template file is missing or unreadable.
+ */
+export function loadTaskManagerPrompt(
+  extensionDir: string,
+  argsString: string,
+): string {
+  const templatePath = path.join(extensionDir, TEMPLATE_REL);
+  const raw = fs.readFileSync(templatePath, "utf-8");
+  const body = stripFrontmatter(raw);
+  const args = parseCommandArgs(argsString);
+  return substituteArgs(body, args).trim();
+}

src/worktree.ts

@@ -172,6 +172,23 @@ export function createWorktree(
 	if (existing && existing.includes(`worktree ${wtDir}`)) {
 		// The worktree is registered — sanity-check it's a valid checkout.
 		if (getGitHead(wtDir)) {
+			// Return the branch the worktree is ACTUALLY checked out on, NOT the
+			// slug recomputed from the (possibly changed) task title. Mismatch
+			// happens routinely on resume: the task agent may have created its
+			// own feature branch (e.g. `proctored-exam-delivery-mode-10-exam-...`)
+			// once it saw the convention in the git log, the title may have been
+			// edited between runs, or an older ralpi version used a different
+			// naming scheme. Returning the slug here makes `git merge <slug>`
+			// fail with "not something we can merge" because no such ref exists —
+			// exactly the spurious merge-conflict we see on resumes.
+			const actual = getCurrentBranch(wtDir);
+			if (actual && actual !== "HEAD" && actual !== "detached") {
+				return { dir: wtDir, branch: actual, mainDir };
+			}
+			// Detached-HEAD worktree (e.g. left by a prior `--detach` fallback).
+			// The slug ref doesn't exist as a branch — create one matching the
+			// slug from the worktree's current HEAD so the merge step resolves.
+			git(`branch "${branch}" HEAD`, mainDir);
 			return { dir: wtDir, branch, mainDir };
 		}
 		// Registered but broken (dir gone / checkout corrupt) — drop its