Accept cookiecutter arguments on the command line for update

This commit adds support for providing cookiecutter arguments on the
command line for `cruft update`. If any arguments are provided on the
command line `cruft update` will always render the template regardless
of whether the user has requested to update to a new template version or
not.

Ideally this change will be applied after
cruft#159 as it's been developed on top
of that PR originally.

cruft/_cli.py

@@ -240,6 +240,12 @@ def update(
             " repository (but no other changes)"
         ),
     ),
+    extra_context: str = typer.Option(
+        "{}",
+        "--extra-context",
+        help="A JSON string describing any extra context to pass to cookiecutter.",
+        show_default=False,
+    ),
 ) -> None:
     if not _commands.update(
         project_dir=project_dir,
@@ -250,6 +256,7 @@ def update(
         checkout=checkout,
         strict=strict,
         allow_untracked_files=allow_untracked_files,
+        extra_context=json.loads(extra_context),
     ):
         raise typer.Exit(1)
 

cruft/_commands/update.py

@@ -1,7 +1,7 @@
 import json
 from pathlib import Path
 from subprocess import DEVNULL, PIPE, CalledProcessError, run  # nosec
-from typing import Optional, Set
+from typing import Any, Dict, Optional, Set
 
 import click
 import typer
@@ -22,6 +22,7 @@ def update(
     checkout: Optional[str] = None,
     strict: bool = True,
     allow_untracked_files: bool = False,
+    extra_context: Optional[Dict[str, Any]] = None,
 ) -> bool:
     """Update specified project's cruft to the latest and greatest release."""
     cruft_file = utils.cruft.get_cruft_file(project_dir)
@@ -53,15 +54,15 @@ def update(
 
             # Bail early if the repo is already up to date and no inputs are asked
             if not (
-                cookiecutter_input or refresh_private_variables
+                extra_content or cookiecutter_input or refresh_private_variables
             ) and utils.cruft.is_project_updated(repo, cruft_state["commit"], last_commit, strict):
                 typer.secho(
                     "Nothing to do, project's cruft is already up to date!", fg=typer.colors.GREEN
                 )
                 return True
 
             # Generate clean outputs via the cookiecutter
-            # from the current cruft state commit of the cookiectter and the updated
+            # from the current cruft state commit of the cookiecutter and the updated
             # cookiecutter.
             # For the current cruft state, we do not try to update the cookiecutter_input
             # because we want to keep the current context input intact.
@@ -79,6 +80,12 @@ def update(
             if refresh_private_variables:
                 _clean_cookiecutter_private_variables(cruft_state)
 
+            # Add new input data from command line to cookiecutter context
+            if extra_context:
+                extra = cruft_state["context"]["cookiecutter"]
+                for k, v in extra_context.items():
+                    extra[k] = v
+
             new_context = utils.generate.cookiecutter_template(
                 output_dir=new_template_dir,
                 repo=repo,

tests/test_cli.py

@@ -378,6 +378,34 @@ def test_update_refresh_private_variables_from_template(
     assert result.exit_code == 0
 
 
+@pytest.mark.parametrize(
+    "template_version",
+    [
+        "input",
+        "input-updated",
+    ],
+)
+def test_update_extra_context(
+    cruft_runner,
+    cookiecutter_dir_input,
+    capfd,
+    template_version,
+):
+    result = cruft_runner(
+        ["update", "--project-dir", cookiecutter_dir_input.as_posix()]
+        + ["-c", template_version, '--extra-context={"input":"extra-context"}'],
+        input="v\ny\n",
+    )
+    git_diff_captured = capfd.readouterr()
+    if template_version == "input_updated":
+        assert "-Initial" in git_diff_captured.out
+        assert "+Updated" in git_diff_captured.out
+    assert "-Input from cookiecutter: some-input" in git_diff_captured.out
+    assert "+Input from cookiecutter: extra-context" in git_diff_captured.out
+    assert "cruft has been updated" in result.stdout
+    assert result.exit_code == 0
+
+
 @pytest.mark.parametrize("args,expected_exit_code", [([], 0), (["--exit-code"], 1), (["-e"], 1)])
 def test_diff_has_diff(args, expected_exit_code, cruft_runner, cookiecutter_dir):
     (cookiecutter_dir / "README.md").write_text("changed content\n")