fix: preserve workspace gitignore entries

pythonlings/core/curriculum.py

@@ -59,10 +59,22 @@ def _copy_path(src: Path, dst: Path, *, overwrite: bool) -> None:
 
 
 def _write_workspace_gitignore(root: Path) -> None:
-    (root / ".gitignore").write_text(
-        "\n".join(GITIGNORE_LINES) + "\n",
-        encoding="utf-8",
-    )
+    gitignore = root / ".gitignore"
+    if gitignore.exists():
+        with gitignore.open(encoding="utf-8", newline="") as file:
+            existing = file.read()
+    else:
+        existing = ""
+
+    existing_lines = set(existing.splitlines())
+    missing_lines = [line for line in GITIGNORE_LINES if line not in existing_lines]
+    if not missing_lines:
+        return
+
+    with gitignore.open("a", encoding="utf-8", newline="") as file:
+        if existing and not existing.endswith(("\n", "\r")):
+            file.write("\n")
+        file.write("\n".join(missing_lines) + "\n")
 
 
 def _sync_originals(root: Path, src_root: Path) -> None:

tests/integration/test_cli_workspace.py

@@ -12,6 +12,12 @@ def test_init_command_creates_workspace(tmp_path: Path) -> None:
     assert (target / "info.toml").exists()
     assert (target / "exercises").is_dir()
     assert (target / "checks").is_dir()
+    assert (target / ".gitignore").read_text(encoding="utf-8").splitlines() == [
+        ".pythonlings/state.json",
+        ".pythonlings_debug.log",
+        "__pycache__/",
+        "*.pyc",
+    ]
 
 
 def test_init_rejects_non_empty_non_workspace_dir(tmp_path: Path, capsys) -> None:
@@ -39,10 +45,21 @@ def test_init_on_existing_workspace_is_friendly_noop(tmp_path: Path, capsys) ->
 
 def test_init_force_overwrites_existing_workspace(tmp_path: Path) -> None:
     target = tmp_path / "ws"
-    assert main(["init", "--path", str(target)]) == 0
+    target.mkdir()
+    gitignore = target / ".gitignore"
+    gitignore.write_text("# Local ignores\n.venv/\n", encoding="utf-8")
+
     code = main(["init", "--path", str(target), "--force"])
+
     assert code == 0
     assert (target / "info.toml").exists()
+    assert gitignore.read_text(encoding="utf-8") == (
+        "# Local ignores\n.venv/\n"
+        ".pythonlings/state.json\n"
+        ".pythonlings_debug.log\n"
+        "__pycache__/\n"
+        "*.pyc\n"
+    )
 
 
 def test_update_via_path_migrates_legacy_state_dir(tmp_path: Path) -> None:
@@ -70,9 +87,18 @@ def test_update_command_preserves_user_exercises(tmp_path: Path) -> None:
     assert main(["init", "--path", str(target)]) == 0
     exercise = next((target / "exercises").rglob("*.py"))
     exercise.write_text("# edited\n", encoding="utf-8")
+    gitignore = target / ".gitignore"
+    gitignore.write_text("# Team rules\n.coverage\n", encoding="utf-8")
 
     code = main(["update", "--path", str(target)])
 
     assert code == 0
     assert exercise.read_text(encoding="utf-8") == "# edited\n"
     assert (target / ".pythonlings" / "originals").is_dir()
+    assert gitignore.read_text(encoding="utf-8") == (
+        "# Team rules\n.coverage\n"
+        ".pythonlings/state.json\n"
+        ".pythonlings_debug.log\n"
+        "__pycache__/\n"
+        "*.pyc\n"
+    )

tests/unit/test_curriculum.py

@@ -43,6 +43,37 @@ def test_init_workspace_refuses_non_empty_directory(tmp_path: Path) -> None:
         raise AssertionError("expected WorkspaceError")
 
 
+def test_force_init_preserves_existing_gitignore_entries(tmp_path: Path) -> None:
+    target = tmp_path / "workspace"
+    target.mkdir()
+    gitignore = target / ".gitignore"
+    original = "# Local ignores\n.env\n\n*.pyc"
+    gitignore.write_text(original, encoding="utf-8")
+
+    curriculum.init_workspace(target, force=True)
+
+    expected = (
+        original
+        + "\n.pythonlings/state.json\n.pythonlings_debug.log\n__pycache__/\n"
+    )
+    assert gitignore.read_text(encoding="utf-8") == expected
+
+    curriculum.init_workspace(target, force=True)
+
+    assert gitignore.read_text(encoding="utf-8") == expected
+
+
+def test_force_init_populates_empty_gitignore(tmp_path: Path) -> None:
+    target = tmp_path / "workspace"
+    target.mkdir()
+    gitignore = target / ".gitignore"
+    gitignore.touch()
+
+    curriculum.init_workspace(target, force=True)
+
+    assert gitignore.read_text(encoding="utf-8").splitlines() == curriculum.GITIGNORE_LINES
+
+
 def test_update_workspace_preserves_user_exercise_edit(tmp_path: Path) -> None:
     target = curriculum.init_workspace(tmp_path / "workspace")
     exercise = next((target / "exercises").rglob("*.py"))
@@ -54,3 +85,19 @@ def test_update_workspace_preserves_user_exercise_edit(tmp_path: Path) -> None:
     original = target / ".pythonlings" / "originals" / exercise.relative_to(target / "exercises")
     assert original.exists()
     assert (target / "solutions" / "_answers.py").exists()
+
+
+def test_update_workspace_preserves_existing_gitignore_entries(tmp_path: Path) -> None:
+    target = curriculum.init_workspace(tmp_path / "workspace")
+    gitignore = target / ".gitignore"
+    original = "# Team rules\n.coverage\n"
+    gitignore.write_text(original, encoding="utf-8")
+
+    curriculum.update_workspace(target)
+
+    expected = original + "\n".join(curriculum.GITIGNORE_LINES) + "\n"
+    assert gitignore.read_text(encoding="utf-8") == expected
+
+    curriculum.update_workspace(target)
+
+    assert gitignore.read_text(encoding="utf-8") == expected