fix: improve mrt init UX — fix db_url quoting bug, clearer prompts and next steps (#54)

* docs: update pre-commit section with args example, fix stale v1.3.0 refs

- pre-commit section: add args example for Alembic and Django, note on
  pre-commit autoupdate, update rev from v1.3.0 to v1.2.0
- Remove (v1.3.0) version labels from section headers for unreleased features
- Update 'What's new' section to reflect v1.2.0 accurately

Closes #35

* fix: improve mrt init UX — fix db_url quoting bug, clearer prompts and next steps

Three issues fixed:

1. db_url quoting bug: when a user typed a literal URL (e.g. sqlite:///test.db),
   it was written as db_url=sqlite:///test.db without quotes — invalid Python.
   Now correctly written as db_url="sqlite:///test.db".

2. Confusing default prompt: the old default was the raw Python expression
   os.environ.get("TEST_DATABASE_URL", "sqlite:///test.db") which is unclear
   for first-time users. Default is now simply sqlite:///test.db with a tip
   explaining the env var pattern for CI.

3. Weak next steps: the completion message now shows numbered steps, static
   analysis command, and a docs link — so users know exactly what to do next.

Also removes unnecessary 'import os' from generated conftest when a literal
URL is used (os is only imported when the url expr references os.environ).

Author: croc100

README.md

@@ -137,7 +137,7 @@ pip install pytest-mrt[oracle]   # python-oracledb
 pip install pytest-mrt[mssql]    # pymssql
 ```
 
-## Auto-fix missing reverse operations (v1.3.0)
+## Auto-fix missing reverse operations
 
 `mrt fix` generates missing reverse operations for both Alembic and Django migrations.
 
@@ -158,18 +158,29 @@ mrt clean-backups --db $DATABASE_URL
 mrt clean-backups --db $DATABASE_URL --label 0042_remove_user_phone --yes
 ```
 
-## pre-commit integration (v1.3.0)
+## pre-commit integration
 
 Add to `.pre-commit-config.yaml` to run `mrt check` automatically before every push:
 
 ```yaml
+# Alembic
 - repo: https://github.com/croc100/pytest-mrt
-  rev: v1.3.0
+  rev: v1.2.0
   hooks:
     - id: mrt-check
+      args: [alembic/versions/]
+
+# Django
+- repo: https://github.com/croc100/pytest-mrt
+  rev: v1.2.0
+  hooks:
+    - id: mrt-check
+      args: [myapp/migrations/]
 ```
 
-## Incremental CI — `--since` (v1.3.0)
+Update `rev` to the latest release tag. Run `pre-commit autoupdate` to keep it current.
+
+## Incremental CI — `--since`
 
 Check only migrations added since a given revision. Keeps CI fast on large codebases:
 
@@ -247,12 +258,13 @@ To suppress all MRT warnings on a line:
 
 Legacy syntax `# mrt: ignore` is still supported for backward compatibility.
 
-## What's new in v1.3.0
+## What's new in v1.2.0
 
-- **Django-aware `mrt fix`** — auto-generates reverse operations and data-safe backup/restore code for `RemoveField` and `DeleteModel`
-- **`mrt clean-backups`** — removes `_mrt_backups` rows after a deployment is confirmed stable
-- **`mrt check --since <revision>`** — incremental scan; only checks migrations added since a given git ref
-- **pre-commit hook** — add two lines to `.pre-commit-config.yaml` and `mrt check` runs automatically before every push
+- **MRT rule codes** (MRT101-MRT902) on all 44 patterns
+- **`# noqa: MRTxxx` suppression** — ruff/flake8-compatible per-line suppression syntax
+- **CLI refactored** into `commands/` subpackage
+- **`mrt check --since <revision>`** — incremental scan; only checks migrations added since a given revision
+- **pre-commit hook** — add to `.pre-commit-config.yaml` and `mrt check` runs automatically before every push
 
 ## Changelog
 

pytest_mrt/commands/init.py

@@ -17,28 +17,47 @@ def _detect_django_project() -> tuple[bool, str | None]:
     return False, None
 
 
+def _db_url_expr(db_url: str) -> str:
+    """Return db_url as a valid Python expression for conftest.py.
+
+    If the value looks like a Python expression (e.g. os.environ.get(...))
+    write it as-is. Otherwise wrap it in quotes so it becomes a string literal.
+    """
+    stripped = db_url.strip()
+    if stripped.startswith("os.") or stripped.startswith('"') or stripped.startswith("'"):
+        return stripped
+    return f'"{stripped}"'
+
+
 def _write_conftest(path: Path, alembic_ini: str, db_url: str) -> None:
+    url_expr = _db_url_expr(db_url)
+    needs_os = "os." in url_expr
+    imports = (
+        "import os\nfrom pytest_mrt import MRTConfig\n"
+        if needs_os
+        else "from pytest_mrt import MRTConfig\n"
+    )
     path.write_text(
-        f"import os\n"
-        f"from pytest_mrt import MRTConfig\n\n\n"
+        f"{imports}\n\n"
         f"def pytest_configure(config):\n"
         f"    config._mrt_config = MRTConfig(\n"
         f'        alembic_ini="{alembic_ini}",\n'
-        f"        db_url={db_url},\n"
-        f'        # skip={{"revision_id": "Reason this is a known issue"}},\n'
+        f"        db_url={url_expr},\n"
+        f'        # skip={{"revision_id": "Reason this migration is intentionally irreversible"}},\n'
         f"    )\n"
     )
 
 
 def _append_conftest(path: Path, alembic_ini: str, db_url: str) -> None:
+    url_expr = _db_url_expr(db_url)
     existing = path.read_text()
     addition = (
         f"\n\n# Added by mrt init\n"
         f"from pytest_mrt import MRTConfig\n\n\n"
         f"def pytest_configure(config):\n"
         f"    config._mrt_config = MRTConfig(\n"
         f'        alembic_ini="{alembic_ini}",\n'
-        f"        db_url={db_url},\n"
+        f"        db_url={url_expr},\n"
         f"    )\n"
     )
     path.write_text(existing + addition)
@@ -53,20 +72,30 @@ def _init_django(detected_settings: str | None) -> None:
         console.print("[yellow]Tip:[/yellow] Set DJANGO_SETTINGS_MODULE or provide it below.")
         settings = typer.prompt("Django settings module (e.g. myproject.settings_test)")
 
+    console.print(
+        "[dim]Tip: use sqlite:///test.db for local testing, "
+        "or set TEST_DATABASE_URL env var for CI.[/dim]"
+    )
     db_url = typer.prompt(
         "Test database URL",
-        default='os.environ.get("TEST_DATABASE_URL", "sqlite:///test.db")',
+        default="sqlite:///test.db",
     )
 
     test_dir = "tests" if Path("tests").exists() else "."
     conftest_path = Path(test_dir) / "conftest.py"
 
+    url_expr = _db_url_expr(db_url)
+    needs_os = "os." in url_expr
+    _imports = (
+        "import os\nfrom pytest_mrt import MRTConfig\n"
+        if needs_os
+        else "from pytest_mrt import MRTConfig\n"
+    )
     django_conftest = (
-        f"import os\n"
-        f"from pytest_mrt import MRTConfig\n\n\n"
+        f"{_imports}\n\n"
         f"def pytest_configure(config):\n"
         f"    config._mrt_config = MRTConfig(\n"
-        f"        db_url={db_url},\n"
+        f"        db_url={url_expr},\n"
         f'        django_settings="{settings}",\n'
         f'        # django_apps=["myapp", "otherapp"],  # restrict to specific apps\n'
         f"    )\n"
@@ -97,11 +126,16 @@ def _init_django(detected_settings: str | None) -> None:
         console.print(f"[green]✓[/green] Created [bold]{test_path}[/bold]")
 
     console.print()
-    console.print("[bold]Next steps:[/bold]")
-    console.print(f"  [cyan]pytest {test_dir}/test_migrations.py -s[/cyan]")
+    console.print("[bold]Setup complete. Next steps:[/bold]")
+    console.print()
+    console.print("  1. Run dynamic rollback tests (requires a test DB):")
+    console.print(f"     [cyan]pytest {test_dir}/test_migrations.py -s[/cyan]")
     console.print()
-    console.print("[dim]Static analysis (no DB needed):[/dim]")
-    console.print("  [cyan]mrt check yourapp/migrations/[/cyan]")
+    console.print("  2. Run static analysis (no DB needed):")
+    console.print("     [cyan]mrt check yourapp/migrations/[/cyan]")
+    console.print()
+    console.print("  [dim]If tests fail, run with -v for details or check docs:[/dim]")
+    console.print("  [dim]https://croc100.github.io/pytest-mrt[/dim]")
 
 
 def init() -> None:
@@ -124,9 +158,13 @@ def init() -> None:
     else:
         found_ini = typer.prompt("Path to alembic.ini", default="alembic.ini")
 
+    console.print(
+        "[dim]Tip: use sqlite:///test.db for local testing, "
+        "or set TEST_DATABASE_URL env var for CI.[/dim]"
+    )
     db_url = typer.prompt(
         "Test database URL",
-        default='os.environ.get("TEST_DATABASE_URL", "sqlite:///test.db")',
+        default="sqlite:///test.db",
     )
 
     test_dir = "tests" if Path("tests").exists() else "."
@@ -153,5 +191,13 @@ def init() -> None:
         console.print(f"[green]✓[/green] Created [bold]{test_path}[/bold]")
 
     console.print()
-    console.print("[bold]Next steps:[/bold]")
-    console.print(f"  [cyan]pytest {test_dir}/test_migrations.py -s[/cyan]")
+    console.print("[bold]Setup complete. Next steps:[/bold]")
+    console.print()
+    console.print("  1. Run dynamic rollback tests (requires a test DB):")
+    console.print(f"     [cyan]pytest {test_dir}/test_migrations.py -s[/cyan]")
+    console.print()
+    console.print("  2. Run static analysis (no DB needed):")
+    console.print(f"     [cyan]mrt check {found_ini.replace('alembic.ini', 'versions/')}[/cyan]")
+    console.print()
+    console.print("  [dim]If tests fail, run with -v for details or check docs:[/dim]")
+    console.print("  [dim]https://croc100.github.io/pytest-mrt[/dim]")