office: worktrees when the folder is a repository, ask before making one, refuse a folder agents cannot see

bin/lib/repo.py

@@ -0,0 +1,69 @@
+"""What a folder needs to be before Paperclip can give a task its own worktree.
+
+A worktree is a git feature: Paperclip makes a directory and a branch per task
+from the project's repository. A folder that is not a repository cannot have
+one, and a repository with no commit has no branch to cut from. Both cases are
+checked here, and neither is repaired without being asked.
+"""
+
+import os
+import subprocess
+
+
+def git(folder, *args, timeout=60):
+    return subprocess.run(["git", "-C", folder] + list(args),
+                          capture_output=True, text=True, timeout=timeout)
+
+
+def is_repo(folder):
+    if not os.path.isdir(folder):
+        return False
+    return git(folder, "rev-parse", "--is-inside-work-tree").stdout.strip() == "true"
+
+
+def has_commit(folder):
+    return git(folder, "rev-parse", "--verify", "HEAD").returncode == 0
+
+
+def branch(folder):
+    """The branch to cut task branches from: what is checked out, else main, else master."""
+    out = git(folder, "symbolic-ref", "--short", "HEAD").stdout.strip()
+    if out:
+        return out
+    for name in ("main", "master"):
+        if git(folder, "rev-parse", "--verify", name).returncode == 0:
+            return name
+    return "main"
+
+
+def untracked_and_modified(folder):
+    out = git(folder, "status", "--porcelain").stdout.splitlines()
+    return len([ln for ln in out if ln.strip()])
+
+
+def has_ignored(folder):
+    return os.path.isfile(os.path.join(folder, ".gitignore"))
+
+
+def make_repo(folder, quiet=False):
+    """git init, add everything, and one commit. Returns (ok, message)."""
+    say = (lambda *_: None) if quiet else print
+    steps = [
+        ("init", ["init", "-b", "main"]),
+    ]
+    for label, args in steps:
+        r = git(folder, *args)
+        if r.returncode != 0:
+            return False, "git %s failed: %s" % (label, (r.stderr or r.stdout).strip()[:200])
+    if git(folder, "add", "-A").returncode != 0:
+        return False, "git add failed"
+    r = git(folder, "-c", "user.name=Paperclip Harness",
+            "-c", "user.email=harness@localhost",
+            "commit", "-q", "-m", "Initial commit, before any Paperclip task")
+    if r.returncode != 0:
+        detail = (r.stderr or r.stdout).strip()
+        if "nothing to commit" in detail:
+            return False, "the folder has no files to commit"
+        return False, "git commit failed: %s" % detail[:200]
+    say("  made a repository on branch %s, one commit" % branch(folder))
+    return True, ""