feat(context): expose a _context_phase context variable (fix #1883)

copier/main.py

@@ -59,7 +59,14 @@
     scantree,
     set_git_alternates,
 )
-from .types import MISSING, AnyByStrDict, JSONSerializable, RelativePath, StrOrPath
+from .types import (
+    MISSING,
+    AnyByStrDict,
+    JSONSerializable,
+    Phase,
+    RelativePath,
+    StrOrPath,
+)
 from .user_data import DEFAULT_DATA, AnswersMap, Question
 from .vcs import get_git
 
@@ -202,6 +209,7 @@ class Worker:
     unsafe: bool = False
     skip_answered: bool = False
     skip_tasks: bool = False
+    phase: Phase = Phase.PROMPT
 
     answers: AnswersMap = field(default_factory=AnswersMap, init=False)
     _cleanup_hooks: list[Callable[[], None]] = field(default_factory=list, init=False)
@@ -350,6 +358,7 @@ def _render_context(self) -> Mapping[str, Any]:
             _copier_conf=conf,
             _folder_name=self.subproject.local_abspath.name,
             _copier_python=sys.executable,
+            _copier_phase=self.phase.value,
         )
 
     def _path_matcher(self, patterns: Iterable[str]) -> Callable[[Path], bool]:
@@ -452,6 +461,7 @@ def _render_allowed(
 
     def _ask(self) -> None:  # noqa: C901
         """Ask the questions of the questionnaire and record their answers."""
+        self.phase = Phase.PROMPT
         result = AnswersMap(
             user_defaults=self.user_defaults,
             init=self.data,
@@ -531,7 +541,12 @@ def answers_relpath(self) -> Path:
         """
         path = self.answers_file or self.template.answers_relpath
         template = self.jinja_env.from_string(str(path))
-        return Path(template.render(**self.answers.combined))
+        return Path(
+            template.render(
+                **self.answers.combined,
+                _copier_phase=self.phase.value,
+            )
+        )
 
     @cached_property
     def all_exclusions(self) -> Sequence[str]:
@@ -598,6 +613,7 @@ def match_skip(self) -> Callable[[Path], bool]:
 
     def _render_template(self) -> None:
         """Render the template in the subproject root."""
+        self.phase = Phase.RENDER
         follow_symlinks = not self.template.preserve_symlinks
         for src in scantree(str(self.template_copy_root), follow_symlinks):
             src_abspath = Path(src.path)
@@ -913,6 +929,7 @@ def run_copy(self) -> None:
                 # TODO Unify printing tools
                 print("")  # padding space
             if not self.skip_tasks:
+                self.phase = Phase.TASKS
                 self._execute_tasks(self.template.tasks)
         except Exception:
             if not was_existing and self.cleanup_on_error:
@@ -1015,6 +1032,7 @@ def _apply_update(self) -> None:  # noqa: C901
             ) as old_worker:
                 old_worker.run_copy()
             # Run pre-migration tasks
+            self.phase = Phase.MIGRATE
             self._execute_tasks(
                 self.template.migration_tasks("before", self.subproject.template)  # type: ignore[arg-type]
             )
@@ -1090,7 +1108,7 @@ def _apply_update(self) -> None:  # noqa: C901
                 self._git_initialize_repo()
                 new_copy_head = git("rev-parse", "HEAD").strip()
             # Extract diff between temporary destination and real destination
-            # with some special handling of newly added files in both the poject
+            # with some special handling of newly added files in both the project
             # and the template.
             with local.cwd(old_copy):
                 # Configure borrowing Git objects from the real destination and

copier/types.py

@@ -1,5 +1,6 @@
 """Complex types, annotations, validators."""
 
+from enum import Enum
 from pathlib import Path
 from typing import (
     Annotated,
@@ -58,3 +59,12 @@ def path_is_relative(value: Path) -> Path:
 
 AbsolutePath = Annotated[Path, AfterValidator(path_is_absolute)]
 RelativePath = Annotated[Path, AfterValidator(path_is_relative)]
+
+
+class Phase(str, Enum):
+    """The known execution phases."""
+
+    PROMPT = "prompt"
+    TASKS = "tasks"
+    MIGRATE = "migrate"
+    RENDER = "render"

copier/user_data.py

@@ -27,7 +27,7 @@
 
 from .errors import InvalidTypeError, UserMessageError
 from .tools import cast_to_bool, cast_to_str, force_str_end
-from .types import MISSING, AnyByStrDict, MissingType, OptStrOrPath, StrOrPath
+from .types import MISSING, AnyByStrDict, MissingType, OptStrOrPath, Phase, StrOrPath
 
 
 # TODO Remove these two functions as well as DEFAULT_DATA in a future release
@@ -446,7 +446,13 @@ def render_value(
                 else value
             )
         try:
-            return template.render({**self.answers.combined, **(extra_answers or {})})
+            return template.render(
+                {
+                    **self.answers.combined,
+                    **(extra_answers or {}),
+                    "_copier_phase": Phase.PROMPT.value,
+                }
+            )
         except UndefinedError as error:
             raise UserMessageError(str(error)) from error
 

docs/creating.md

@@ -125,6 +125,10 @@ The absolute path of the Python interpreter running Copier.
 
 The name of the project root directory.
 
+### `_copier_phase`
+
+The current phase, one of `"prompt"`,`"tasks"`, `"migrate"` or `"render"`.
+
 ## Variables (context-specific)
 
 Some rendering contexts provide variables unique to them:

tests/test_copy.py

@@ -1042,3 +1042,10 @@ def test_templated_choices(tmp_path_factory: pytest.TempPathFactory, spec: str)
     )
     copier.run_copy(str(src), dst, data={"q": "two"})
     assert yaml.safe_load((dst / "q.txt").read_text()) == "two"
+
+
+def test_copier_phase_variable(tmp_path_factory: pytest.TempPathFactory) -> None:
+    src, dst = map(tmp_path_factory.mktemp, ("src", "dst"))
+    build_file_tree({src / "{{ _copier_phase }}": ""})
+    copier.run_copy(str(src), dst)
+    assert (dst / "render").exists()

tests/test_migrations.py

@@ -521,3 +521,32 @@ def test_migration_jinja_variables(
             assert f"{variable}={value}" in vars
         else:
             assert f"{variable}=" in vars
+
+
+def test_copier_phase_variable(tmp_path_factory: pytest.TempPathFactory) -> None:
+    """Test that the Phase variable is properly set."""
+    src, dst = map(tmp_path_factory.mktemp, ("src", "dst"))
+
+    with local.cwd(src):
+        build_file_tree(
+            {
+                **COPIER_ANSWERS_FILE,
+                "copier.yml": (
+                    """\
+                    _migrations:
+                        - touch {{ _copier_phase }}
+                    """
+                ),
+            }
+        )
+        git_save(tag="v1")
+    with local.cwd(dst):
+        run_copy(src_path=str(src))
+        git_save()
+
+    with local.cwd(src):
+        git("tag", "v2")
+    with local.cwd(dst):
+        run_update(defaults=True, overwrite=True, unsafe=True)
+
+    assert (dst / "migrate").is_file()

tests/test_tasks.py

@@ -164,3 +164,19 @@ def test_os_specific_tasks(
     monkeypatch.setattr("copier.main.OS", os)
     copier.run_copy(str(src), dst, unsafe=True)
     assert (dst / filename).exists()
+
+
+def test_copier_phase_variable(tmp_path_factory: pytest.TempPathFactory) -> None:
+    src, dst = map(tmp_path_factory.mktemp, ("src", "dst"))
+    build_file_tree(
+        {
+            (src / "copier.yml"): (
+                """
+                _tasks:
+                    - touch {{ _copier_phase }}
+                """
+            )
+        }
+    )
+    copier.run_copy(str(src), dst, unsafe=True)
+    assert (dst / "tasks").exists()

tests/test_templated_prompt.py

@@ -563,3 +563,22 @@ def test_multiselect_choices_with_templated_default_value(
         "python_version": "3.11",
         "github_runner_python_version": ["3.11"],
     }
+
+
+def test_copier_phase_variable(
+    tmp_path_factory: pytest.TempPathFactory,
+    spawn: Spawn,
+) -> None:
+    src, dst = map(tmp_path_factory.mktemp, ("src", "dst"))
+    build_file_tree(
+        {
+            (src / "copier.yml"): """\
+                phase:
+                    type: str
+                    default: "{{ _copier_phase }}"
+            """
+        }
+    )
+    tui = spawn(COPIER_PATH + ("copy", str(src), str(dst)), timeout=10)
+    expect_prompt(tui, "phase", "str")
+    tui.expect_exact("prompt")