feat: honor ADR_TEMPLATE env var for decree new

CHANGELOG.md

@@ -1,6 +1,13 @@
 
 # changelog
 
+## Unreleased
+
+### Added
+
+* Allow configuring `decree new` templates via `ADR_TEMPLATE`, still overridable by
+  the `--template` flag.
+
 ## 0.1.0
 
 * Initial CLI and API with `init`, `new`, `link`, `list`, `generate toc`,

README.md

@@ -33,7 +33,15 @@ decree generate graph  # exits non-zero, not implemented
 
 * `ADR_DATE`: if set, used verbatim as the ADR date
 * `DECREE_TZ`: IANA timezone for date formatting (default: `UTC`)
-* `ADR_TEMPLATE`: path to a custom template file
+* `ADR_TEMPLATE`: path to a custom template file used by `decree new` when
+  `--template` is not provided
+
+`decree new --template` overrides `ADR_TEMPLATE`, which overrides the built-in template.
+
+```
+ADR_TEMPLATE=/path/to/template.md decree new "Use beartype"
+decree new --template /other/path.md "Use beartype"
+```
 
 ## license
 

src/decree/cli.py

@@ -11,6 +11,23 @@
 app = typer.Typer(add_completion=False, help="Decree: typed Python reimplementation of adr-tools")
 
 
+def _resolve_template_option(template: Path | None) -> Path | None:
+    if template is None:
+        return None
+    candidate = template.expanduser().resolve()
+    if not candidate.exists():
+        raise typer.BadParameter(f"Template file not found: {candidate}")
+    if not candidate.is_file():
+        raise typer.BadParameter(f"Template path is not a file: {candidate}")
+    try:
+        with candidate.open("r", encoding="utf-8"):
+            pass
+    except OSError as exc:
+        detail = exc.strerror or str(exc)
+        raise typer.BadParameter(f"Could not read template file {candidate}: {detail}") from exc
+    return candidate
+
+
 @app.command()
 def init(
     dir: Annotated[
@@ -28,11 +45,21 @@ def new(
     status: Annotated[
         AdrStatus, typer.Option("--status", case_sensitive=False)
     ] = AdrStatus.Accepted,
-    template: Annotated[Path | None, typer.Option("--template", help="Path to template")] = None,
+    template: Annotated[
+        Path | None,
+        typer.Option(
+            "--template",
+            help="Path to template (can also be set via ADR_TEMPLATE)",
+            envvar="ADR_TEMPLATE",
+        ),
+    ] = None,
     dir: Annotated[Path | None, typer.Option("--dir", help="ADR directory")] = None,
 ) -> None:
     """Create a new ADR."""
-    rec = AdrLog(dir or Path("doc/adr")).new(" ".join(title), status=status, template=template)
+    template_path = _resolve_template_option(template)
+    rec = AdrLog(dir or Path("doc/adr")).new(
+        " ".join(title), status=status, template=template_path
+    )
     typer.echo(str(rec.path))
 
 

tests/test_new_template_env.py

@@ -0,0 +1,99 @@
+from __future__ import annotations
+
+from pathlib import Path
+
+import pytest
+from typer.testing import CliRunner
+
+from decree.cli import app
+
+runner = CliRunner()
+
+
+def _ensure_adr_dir(base: Path) -> Path:
+    target = base / "doc" / "adr"
+    target.mkdir(parents=True, exist_ok=True)
+    return target
+
+
+def _read_created_path(result_stdout: str) -> Path:
+    created = Path(result_stdout.strip())
+    assert created.exists()
+    return created
+
+
+def test_new_uses_template_from_env(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    target_dir = _ensure_adr_dir(tmp_path)
+    template_path = tmp_path / "template-env.md"
+    sentinel = "__ENV_SENTINEL__"
+    template_path.write_text(f"{sentinel}\n", encoding="utf-8")
+    monkeypatch.setenv("ADR_TEMPLATE", str(template_path))
+
+    result = runner.invoke(app, ["new", "--dir", str(target_dir), "Env", "First"])
+
+    assert result.exit_code == 0, result.stderr
+    created_path = _read_created_path(result.stdout)
+    content = created_path.read_text(encoding="utf-8")
+    assert sentinel in content
+
+
+def test_cli_template_overrides_env(tmp_path: Path, monkeypatch: pytest.MonkeyPatch) -> None:
+    target_dir = _ensure_adr_dir(tmp_path)
+    env_template = tmp_path / "template-env.md"
+    env_template.write_text("__ENV_ONLY__\n", encoding="utf-8")
+    cli_template = tmp_path / "template-cli.md"
+    cli_sentinel = "__CLI_SENTINEL__"
+    cli_template.write_text(f"{cli_sentinel}\n", encoding="utf-8")
+    monkeypatch.setenv("ADR_TEMPLATE", str(env_template))
+
+    result = runner.invoke(
+        app,
+        [
+            "new",
+            "--dir",
+            str(target_dir),
+            "--template",
+            str(cli_template),
+            "Cli",
+            "Wins",
+        ],
+    )
+
+    assert result.exit_code == 0, result.stderr
+    created_path = _read_created_path(result.stdout)
+    content = created_path.read_text(encoding="utf-8")
+    assert cli_sentinel in content
+    assert "__ENV_ONLY__" not in content
+
+
+def test_new_uses_default_template_when_not_overridden(tmp_path: Path) -> None:
+    target_dir = _ensure_adr_dir(tmp_path)
+
+    result = runner.invoke(
+        app,
+        ["new", "--dir", str(target_dir), "Default", "Template"],
+    )
+
+    assert result.exit_code == 0, result.stderr
+    created_path = _read_created_path(result.stdout)
+    content = created_path.read_text(encoding="utf-8")
+    assert "__ENV_SENTINEL__" not in content
+    assert "__CLI_SENTINEL__" not in content
+
+
+def test_new_errors_on_missing_template_from_env(
+    tmp_path: Path, monkeypatch: pytest.MonkeyPatch
+) -> None:
+    target_dir = _ensure_adr_dir(tmp_path)
+    missing = tmp_path / "missing-template.md"
+    monkeypatch.setenv("ADR_TEMPLATE", str(missing))
+
+    result = runner.invoke(
+        app,
+        ["new", "--dir", str(target_dir), "Missing", "Template"],
+    )
+
+    assert result.exit_code != 0
+    output = result.stderr
+    assert str(missing.resolve()) in output
+    assert "Template" in output