main.py

Main functions and classes, used to generate or update projects.

Worker

Copier process state manager.

This class represents the state of a copier work, and contains methods to actually produce the desired work.

To use it properly, use it as a context manager and fill all dataclass fields.

Then, execute one of its main methods, which are prefixed with run_:

• run_copy to copy a subproject.
• run_recopy to recopy a subproject.
• run_update to update a subproject.

Example

with Worker(
    src_path="https://github.com/copier-org/autopretty.git", "output"
) as worker:
    worker.run_copy()

Attributes:

Name	Type	Description
src_path	Optional[str]	String that can be resolved to a template path, be it local or remote. See copier.vcs.get_repo. If it is None, then it means that you are updating a project, and the original src_path will be obtained from the answers file.
dst_path	Path	Destination path where to render the subproject.
answers_file	Optional[RelativePath]	Indicates the path for the answers file. The path must be relative to dst_path. If it is None, the default value will be obtained from copier.template.Template.answers_relpath.
vcs_ref	OptStr	Specify the VCS tag/commit to use in the template.
data	AnyByStrDict	Answers to the questionary defined in the template.
exclude	StrSeq	User-chosen additional file exclusion patterns.
use_prereleases	bool	Consider prereleases when detecting the latest one? See use_prereleases. Useless if specifying a vcs_ref.
skip_if_exists	StrSeq	User-chosen additional file skip patterns.
cleanup_on_error	bool	Delete dst_path if there's an error? See cleanup_on_error.
defaults	bool	When True, use default answers to questions, which might be null if not specified. See defaults.
user_defaults	AnyByStrDict	Specify user defaults that may override a template's defaults during question prompts.
overwrite	bool	When True, Overwrite files that already exist, without asking. See overwrite.
pretend	bool	When True, produce no real rendering. See pretend.
quiet	bool	When True, disable all output. See quiet.
conflict	Literal['inline', 'rej']	One of "inline" (default), "rej".
context_lines	PositiveInt	Lines of context to consider when solving conflicts in updates. With more lines, context resolution is more accurate, but it will also produce more conflicts if your subproject has evolved. With less lines, context resolution is less accurate, but it will respect better the evolution of your subproject.
unsafe	bool	When True, allow usage of unsafe templates. See unsafe

Source code in copier/main.py

@dataclass(config=ConfigDict(extra="forbid"))
class Worker:
    """Copier process state manager.

    This class represents the state of a copier work, and contains methods to
    actually produce the desired work.

    To use it properly, use it as a context manager and fill all dataclass fields.

    Then, execute one of its main methods, which are prefixed with `run_`:

    -   [run_copy][copier.main.Worker.run_copy] to copy a subproject.
    -   [run_recopy][copier.main.Worker.run_recopy] to recopy a subproject.
    -   [run_update][copier.main.Worker.run_update] to update a subproject.

    Example:
        ```python
        with Worker(
            src_path="https://github.com/copier-org/autopretty.git", "output"
        ) as worker:
            worker.run_copy()
        ```

    Attributes:
        src_path:
            String that can be resolved to a template path, be it local or remote.

            See [copier.vcs.get_repo][].

            If it is `None`, then it means that you are
            [updating a project][updating-a-project], and the original
            `src_path` will be obtained from
            [the answers file][the-copier-answersyml-file].

        dst_path:
            Destination path where to render the subproject.

        answers_file:
            Indicates the path for [the answers file][the-copier-answersyml-file].

            The path must be relative to `dst_path`.

            If it is `None`, the default value will be obtained from
            [copier.template.Template.answers_relpath][].

        vcs_ref:
            Specify the VCS tag/commit to use in the template.

        data:
            Answers to the questionary defined in the template.

        exclude:
            User-chosen additional [file exclusion patterns][exclude].

        use_prereleases:
            Consider prereleases when detecting the *latest* one?

            See [use_prereleases][].

            Useless if specifying a [vcs_ref][].

        skip_if_exists:
            User-chosen additional [file skip patterns][skip_if_exists].

        cleanup_on_error:
            Delete `dst_path` if there's an error?

            See [cleanup_on_error][].

        defaults:
            When `True`, use default answers to questions, which might be null if not specified.

            See [defaults][].

        user_defaults:
            Specify user defaults that may override a template's defaults during question prompts.

        overwrite:
            When `True`, Overwrite files that already exist, without asking.

            See [overwrite][].

        pretend:
            When `True`, produce no real rendering.

            See [pretend][].

        quiet:
            When `True`, disable all output.

            See [quiet][].

        conflict:
            One of "inline" (default), "rej".

        context_lines:
            Lines of context to consider when solving conflicts in updates.

            With more lines, context resolution is more accurate, but it will
            also produce more conflicts if your subproject has evolved.

            With less lines, context resolution is less accurate, but it will
            respect better the evolution of your subproject.

        unsafe:
            When `True`, allow usage of unsafe templates.

            See [unsafe][]
    """

    src_path: Optional[str] = None
    dst_path: Path = Path(".")
    answers_file: Optional[RelativePath] = None
    vcs_ref: OptStr = None
    data: AnyByStrDict = field(default_factory=dict)
    exclude: StrSeq = ()
    use_prereleases: bool = False
    skip_if_exists: StrSeq = ()
    cleanup_on_error: bool = True
    defaults: bool = False
    user_defaults: AnyByStrDict = field(default_factory=dict)
    overwrite: bool = False
    pretend: bool = False
    quiet: bool = False
    conflict: Literal["inline", "rej"] = "inline"
    context_lines: PositiveInt = 3
    unsafe: bool = False
    skip_answered: bool = False

    answers: AnswersMap = field(default_factory=AnswersMap, init=False)
    _cleanup_hooks: List[Callable] = field(default_factory=list, init=False)

    def __enter__(self):
        """Allow using worker as a context manager."""
        return self

    def __exit__(self, type, value, traceback):
        """Clean up garbage files after worker usage ends."""
        if value is not None:
            # exception was raised from code inside context manager:
            # try to clean up, ignoring any exception, then re-raise
            with suppress(Exception):
                self._cleanup()
            raise value
        # otherwise clean up and let any exception bubble up
        self._cleanup()

    def _cleanup(self):
        """Execute all stored cleanup methods."""
        for method in self._cleanup_hooks:
            method()

    def _check_unsafe(self, mode: Literal["copy", "update"]) -> None:
        """Check whether a template uses unsafe features."""
        if self.unsafe:
            return
        features: Set[str] = set()
        if self.template.jinja_extensions:
            features.add("jinja_extensions")
        if self.template.tasks:
            features.add("tasks")
        if mode == "update" and self.subproject.template:
            if self.subproject.template.jinja_extensions:
                features.add("jinja_extensions")
            if self.subproject.template.tasks:
                features.add("tasks")
            for stage in get_args(Literal["before", "after"]):
                if self.template.migration_tasks(stage, self.subproject.template):
                    features.add("migrations")
                    break
        if features:
            raise UnsafeTemplateError(sorted(features))

    def _print_message(self, message: str) -> None:
        if message and not self.quiet:
            print(self._render_string(message), file=sys.stderr)

    def _answers_to_remember(self) -> Mapping:
        """Get only answers that will be remembered in the copier answers file."""
        # All internal values must appear first
        answers: AnyByStrDict = {}
        commit = self.template.commit
        src = self.template.url
        for key, value in (("_commit", commit), ("_src_path", src)):
            if value is not None:
                answers[key] = value
        # Other data goes next
        answers.update(
            (str(k), v)
            for (k, v) in self.answers.combined.items()
            if not k.startswith("_")
            and k not in self.answers.hidden
            and k not in self.template.secret_questions
            and k in self.template.questions_data
            and isinstance(k, JSONSerializable)
            and isinstance(v, JSONSerializable)
        )
        return answers

    def _execute_tasks(self, tasks: Sequence[Task]) -> None:
        """Run the given tasks.

        Arguments:
            tasks: The list of tasks to run.
        """
        for i, task in enumerate(tasks):
            task_cmd = task.cmd
            if isinstance(task_cmd, str):
                task_cmd = self._render_string(task_cmd)
                use_shell = True
            else:
                task_cmd = [self._render_string(str(part)) for part in task_cmd]
                use_shell = False
            if not self.quiet:
                print(
                    colors.info
                    | f" > Running task {i + 1} of {len(tasks)}: {task_cmd}",
                    file=sys.stderr,
                )
            if self.pretend:
                continue
            with local.cwd(self.subproject.local_abspath), local.env(**task.extra_env):
                subprocess.run(task_cmd, shell=use_shell, check=True, env=local.env)

    def _render_context(self) -> Mapping:
        """Produce render context for Jinja."""
        # Backwards compatibility
        # FIXME Remove it?
        conf = asdict(self)
        conf.pop("_cleanup_hooks")
        conf.update(
            {
                "answers_file": self.answers_relpath,
                "src_path": self.template.local_abspath,
                "vcs_ref_hash": self.template.commit_hash,
                "sep": os.sep,
                "os": OS,
            }
        )

        return dict(
            DEFAULT_DATA,
            **self.answers.combined,
            _copier_answers=self._answers_to_remember(),
            _copier_conf=conf,
            _folder_name=self.subproject.local_abspath.name,
            _copier_python=sys.executable,
        )

    def _path_matcher(self, patterns: Iterable[str]) -> Callable[[Path], bool]:
        """Produce a function that matches against specified patterns."""
        # TODO Is normalization really needed?
        normalized_patterns = (normalize("NFD", pattern) for pattern in patterns)
        spec = PathSpec.from_lines("gitwildmatch", normalized_patterns)
        return spec.match_file

    def _solve_render_conflict(self, dst_relpath: Path):
        """Properly solve render conflicts.

        It can ask the user if running in interactive mode.
        """
        assert not dst_relpath.is_absolute()
        printf(
            "conflict",
            dst_relpath,
            style=Style.DANGER,
            quiet=self.quiet,
            file_=sys.stderr,
        )
        if self.match_skip(dst_relpath):
            printf(
                "skip",
                dst_relpath,
                style=Style.OK,
                quiet=self.quiet,
                file_=sys.stderr,
            )
            return False
        if self.overwrite or dst_relpath == self.answers_relpath:
            printf(
                "overwrite",
                dst_relpath,
                style=Style.WARNING,
                quiet=self.quiet,
                file_=sys.stderr,
            )
            return True
        return bool(ask(f" Overwrite {dst_relpath}?", default=True))

    def _render_allowed(
        self,
        dst_relpath: Path,
        is_dir: bool = False,
        is_symlink: bool = False,
        expected_contents: Union[bytes, Path] = b"",
    ) -> bool:
        """Determine if a file or directory can be rendered.

        Args:
            dst_relpath:
                Relative path to destination.
            is_dir:
                Indicate if the path must be treated as a directory or not.
            is_symlink:
                Indicate if the path must be treated as a symlink or not.
            expected_contents:
                Used to compare existing file contents with them. Allows to know if
                rendering is needed.
        """
        assert not dst_relpath.is_absolute()
        assert not expected_contents or not is_dir, "Dirs cannot have expected content"
        dst_abspath = Path(self.subproject.local_abspath, dst_relpath)
        if dst_relpath != Path(".") and self.match_exclude(dst_relpath):
            return False
        try:
            previous_content: Union[bytes, Path]
            if is_symlink:
                previous_content = readlink(dst_abspath)
            else:
                previous_content = dst_abspath.read_bytes()
        except FileNotFoundError:
            printf(
                "create",
                dst_relpath,
                style=Style.OK,
                quiet=self.quiet,
                file_=sys.stderr,
            )
            return True
        except PermissionError as error:
            # HACK https://bugs.python.org/issue43095
            if not (error.errno == 13 and platform.system() == "Windows"):
                raise
        except IsADirectoryError:
            assert is_dir
        if is_dir or previous_content == expected_contents:
            printf(
                "identical",
                dst_relpath,
                style=Style.IGNORE,
                quiet=self.quiet,
                file_=sys.stderr,
            )
            return True
        return self._solve_render_conflict(dst_relpath)

    def _ask(self) -> None:
        """Ask the questions of the questionary and record their answers."""
        result = AnswersMap(
            user_defaults=self.user_defaults,
            init=self.data,
            last=self.subproject.last_answers,
            metadata=self.template.metadata,
        )

        for var_name, details in self.template.questions_data.items():
            question = Question(
                answers=result,
                jinja_env=self.jinja_env,
                var_name=var_name,
                **details,
            )
            if self.skip_answered and var_name in result.last:
                # Skip a question when the user already answered it.
                continue
            # Skip a question when the skip condition is met.
            if not question.get_when():
                # Omit its answer from the answers file.
                result.hide(var_name)
                # Skip immediately to the next question when it has no default
                # value.
                if question.default is MISSING:
                    continue
            if var_name in result.init:
                # Try to parse the answer value.
                answer = question.parse_answer(result.init[var_name])
                # Try to validate the answer value if the question has a
                # validator.
                question.validate_answer(answer)
                # At this point, the answer value is valid. Do not ask the
                # question again, but set answer as the user's answer instead.
                result.user[var_name] = answer
                continue

            # Display TUI and ask user interactively only without --defaults
            try:
                if self.defaults:
                    new_answer = question.get_default()
                    if new_answer is MISSING:
                        raise ValueError(f'Question "{var_name}" is required')
                else:
                    new_answer = unsafe_prompt(
                        [question.get_questionary_structure()],
                        answers={question.var_name: question.get_default()},
                    )[question.var_name]
            except KeyboardInterrupt as err:
                raise CopierAnswersInterrupt(result, question, self.template) from err
            result.user[var_name] = new_answer

        self.answers = result

    @cached_property
    def answers_relpath(self) -> Path:
        """Obtain the proper relative path for the answers file.

        It comes from:

        1. User choice.
        2. Template default.
        3. Copier default.
        """
        path = self.answers_file or self.template.answers_relpath
        template = self.jinja_env.from_string(str(path))
        return Path(template.render(**self.answers.combined))

    @cached_property
    def all_exclusions(self) -> StrSeq:
        """Combine default, template and user-chosen exclusions."""
        return self.template.exclude + tuple(self.exclude)

    @cached_property
    def jinja_env(self) -> SandboxedEnvironment:
        """Return a pre-configured Jinja environment.

        Respects template settings.
        """
        paths = [str(self.template.local_abspath)]
        loader = FileSystemLoader(paths)
        default_extensions = [
            "jinja2_ansible_filters.AnsibleCoreFiltersExtension",
        ]
        extensions = default_extensions + list(self.template.jinja_extensions)
        # We want to minimize the risk of hidden malware in the templates
        # so we use the SandboxedEnvironment instead of the regular one.
        # Of course we still have the post-copy tasks to worry about, but at least
        # they are more visible to the final user.
        try:
            env = SandboxedEnvironment(
                loader=loader, extensions=extensions, **self.template.envops
            )
        except ModuleNotFoundError as error:
            raise ExtensionNotFoundError(
                f"Copier could not load some Jinja extensions:\n{error}\n"
                "Make sure to install these extensions alongside Copier itself.\n"
                "See the docs at https://copier.readthedocs.io/en/latest/configuring/#jinja_extensions"
            )
        # patch the `to_json` filter to support Pydantic dataclasses
        env.filters["to_json"] = partial(
            env.filters["to_json"], default=to_jsonable_python
        )

        # Add a global function to join filesystem paths.
        separators = {
            "posix": "/",
            "windows": "\\",
            "native": os.path.sep,
        }

        def _pathjoin(
            *path: str, mode: Literal["posix", "windows", "native"] = "posix"
        ) -> str:
            return separators[mode].join(path)

        env.globals["pathjoin"] = _pathjoin
        return env

    @cached_property
    def match_exclude(self) -> Callable[[Path], bool]:
        """Get a callable to match paths against all exclusions."""
        return self._path_matcher(self.all_exclusions)

    @cached_property
    def match_skip(self) -> Callable[[Path], bool]:
        """Get a callable to match paths against all skip-if-exists patterns."""
        return self._path_matcher(
            map(
                self._render_string,
                tuple(chain(self.skip_if_exists, self.template.skip_if_exists)),
            )
        )

    def _render_file(self, src_abspath: Path) -> None:
        """Render one file.

        Args:
            src_abspath:
                The absolute path to the file that will be rendered.
        """
        # TODO Get from main.render_file()
        assert src_abspath.is_absolute()
        src_relpath = src_abspath.relative_to(self.template.local_abspath).as_posix()
        src_renderpath = src_abspath.relative_to(self.template_copy_root)
        dst_relpath = self._render_path(src_renderpath)
        if dst_relpath is None:
            return
        if src_abspath.name.endswith(self.template.templates_suffix):
            try:
                tpl = self.jinja_env.get_template(src_relpath)
            except UnicodeDecodeError:
                if self.template.templates_suffix:
                    # suffix is not empty, re-raise
                    raise
                # suffix is empty, fallback to copy
                new_content = src_abspath.read_bytes()
            else:
                new_content = tpl.render(**self._render_context()).encode()
        else:
            new_content = src_abspath.read_bytes()
        dst_abspath = Path(self.subproject.local_abspath, dst_relpath)
        src_mode = src_abspath.stat().st_mode
        if not self._render_allowed(dst_relpath, expected_contents=new_content):
            return
        if not self.pretend:
            dst_abspath.parent.mkdir(parents=True, exist_ok=True)
            dst_abspath.write_bytes(new_content)
            dst_abspath.chmod(src_mode)

    def _render_symlink(self, src_abspath: Path) -> None:
        """Render one symlink.

        Args:
            src_abspath:
                Symlink to be rendered. It must be an absolute path within
                the template.
        """
        assert src_abspath.is_absolute()
        src_relpath = src_abspath.relative_to(self.template_copy_root)
        dst_relpath = self._render_path(src_relpath)
        if dst_relpath is None:
            return
        dst_abspath = Path(self.subproject.local_abspath, dst_relpath)

        src_target = readlink(src_abspath)
        if src_abspath.name.endswith(self.template.templates_suffix):
            dst_target = Path(self._render_string(str(src_target)))
        else:
            dst_target = src_target

        if not self._render_allowed(
            dst_relpath,
            expected_contents=dst_target,
            is_symlink=True,
        ):
            return

        if not self.pretend:
            # symlink_to doesn't overwrite existing files, so delete it first
            if dst_abspath.is_symlink() or dst_abspath.exists():
                dst_abspath.unlink()
            dst_abspath.symlink_to(dst_target)
            if sys.platform == "darwin":
                # Only macOS supports permissions on symlinks.
                # Other platforms just copy the permission of the target
                src_mode = src_abspath.lstat().st_mode
                dst_abspath.lchmod(src_mode)

    def _render_folder(self, src_abspath: Path) -> None:
        """Recursively render a folder.

        Args:
            src_path:
                Folder to be rendered. It must be an absolute path within
                the template.
        """
        assert src_abspath.is_absolute()
        src_relpath = src_abspath.relative_to(self.template_copy_root)
        dst_relpath = self._render_path(src_relpath)
        if dst_relpath is None:
            return
        if not self._render_allowed(dst_relpath, is_dir=True):
            return
        dst_abspath = Path(self.subproject.local_abspath, dst_relpath)
        if not self.pretend:
            dst_abspath.mkdir(parents=True, exist_ok=True)
        for file in src_abspath.iterdir():
            if file.is_symlink() and self.template.preserve_symlinks:
                self._render_symlink(file)
            elif file.is_dir():
                self._render_folder(file)
            else:
                self._render_file(file)

    def _render_path(self, relpath: Path) -> Optional[Path]:
        """Render one relative path.

        Args:
            relpath:
                The relative path to be rendered. Obviously, it can be templated.
        """
        is_template = relpath.name.endswith(self.template.templates_suffix)
        templated_sibling = (
            self.template.local_abspath / f"{relpath}{self.template.templates_suffix}"
        )
        # With an empty suffix, the templated sibling always exists.
        if templated_sibling.exists() and self.template.templates_suffix:
            return None
        if self.template.templates_suffix and is_template:
            relpath = relpath.with_suffix("")
        rendered_parts = []
        for part in relpath.parts:
            # Skip folder if any part is rendered as an empty string
            part = self._render_string(part)
            if not part:
                return None
            # {{ _copier_conf.answers_file }} becomes the full path; in that case,
            # restore part to be just the end leaf
            if str(self.answers_relpath) == part:
                part = Path(part).name
            rendered_parts.append(part)
        result = Path(*rendered_parts)
        if not is_template:
            templated_sibling = (
                self.template.local_abspath
                / f"{result}{self.template.templates_suffix}"
            )
            if templated_sibling.exists():
                return None
        return result

    def _render_string(self, string: str) -> str:
        """Render one templated string.

        Args:
            string:
                The template source string.
        """
        tpl = self.jinja_env.from_string(string)
        return tpl.render(**self._render_context())

    @cached_property
    def subproject(self) -> Subproject:
        """Get related subproject."""
        result = Subproject(
            local_abspath=self.dst_path.absolute(),
            answers_relpath=self.answers_file or Path(".copier-answers.yml"),
        )
        self._cleanup_hooks.append(result._cleanup)
        return result

    @cached_property
    def template(self) -> Template:
        """Get related template."""
        url = self.src_path
        if not url:
            if self.subproject.template is None:
                raise TypeError("Template not found")
            url = str(self.subproject.template.url)
        result = Template(
            url=url, ref=self.vcs_ref, use_prereleases=self.use_prereleases
        )
        self._cleanup_hooks.append(result._cleanup)
        return result

    @cached_property
    def template_copy_root(self) -> Path:
        """Absolute path from where to start copying.

        It points to the cloned template local abspath + the rendered subdir, if any.
        """
        subdir = self._render_string(self.template.subdirectory) or ""
        return self.template.local_abspath / subdir

    # Main operations
    def run_copy(self) -> None:
        """Generate a subproject from zero, ignoring what was in the folder.

        If `dst_path` was missing, it will be
        created. Otherwise, `src_path` be rendered
        directly into it, without worrying about evolving what was there
        already.

        See [generating a project][generating-a-project].
        """
        self._check_unsafe("copy")
        self._print_message(self.template.message_before_copy)
        self._ask()
        was_existing = self.subproject.local_abspath.exists()
        src_abspath = self.template_copy_root
        try:
            if not self.quiet:
                # TODO Unify printing tools
                print(
                    f"\nCopying from template version {self.template.version}",
                    file=sys.stderr,
                )
            self._render_folder(src_abspath)
            if not self.quiet:
                # TODO Unify printing tools
                print("")  # padding space
            self._execute_tasks(self.template.tasks)
        except Exception:
            if not was_existing and self.cleanup_on_error:
                rmtree(self.subproject.local_abspath)
            raise
        self._print_message(self.template.message_after_copy)
        if not self.quiet:
            # TODO Unify printing tools
            print("")  # padding space

    def run_recopy(self) -> None:
        """Update a subproject, keeping answers but discarding evolution."""
        if self.subproject.template is None:
            raise UserMessageError(
                "Cannot recopy because cannot obtain old template references "
                f"from `{self.subproject.answers_relpath}`."
            )
        with replace(self, src_path=self.subproject.template.url) as new_worker:
            return new_worker.run_copy()

    def run_update(self) -> None:
        """Update a subproject that was already generated.

        See [updating a project][updating-a-project].
        """
        self._check_unsafe("update")
        # Check all you need is there
        if self.subproject.vcs != "git":
            raise UserMessageError(
                "Updating is only supported in git-tracked subprojects."
            )
        if self.subproject.is_dirty():
            raise UserMessageError(
                "Destination repository is dirty; cannot continue. "
                "Please commit or stash your local changes and retry."
            )
        if self.subproject.template is None or self.subproject.template.ref is None:
            raise UserMessageError(
                "Cannot update because cannot obtain old template references "
                f"from `{self.subproject.answers_relpath}`."
            )
        if self.template.commit is None:
            raise UserMessageError(
                "Updating is only supported in git-tracked templates."
            )
        if not self.subproject.template.version:
            raise UserMessageError(
                "Cannot update: version from last update not detected."
            )
        if not self.template.version:
            raise UserMessageError("Cannot update: version from template not detected.")
        if self.subproject.template.version > self.template.version:
            raise UserMessageError(
                f"You are downgrading from {self.subproject.template.version} to {self.template.version}. "
                "Downgrades are not supported."
            )
        if not self.overwrite:
            # Only git-tracked subprojects can be updated, so the user can
            # review the diff before committing; so we can safely avoid
            # asking for confirmation
            raise UserMessageError("Enable overwrite to update a subproject.")
        self._print_message(self.template.message_before_update)
        if not self.quiet:
            # TODO Unify printing tools
            print(
                f"Updating to template version {self.template.version}", file=sys.stderr
            )
        self._apply_update()
        self._print_message(self.template.message_after_update)

    def _apply_update(self):
        git = get_git()
        subproject_top = Path(
            git(
                "-C",
                self.subproject.local_abspath,
                "rev-parse",
                "--show-toplevel",
            ).strip()
        )
        subproject_subdir = self.subproject.local_abspath.relative_to(subproject_top)

        with TemporaryDirectory(
            prefix=f"{__name__}.old_copy."
        ) as old_copy, TemporaryDirectory(prefix=f"{__name__}.new_copy.") as new_copy:
            # Copy old template into a temporary destination
            with replace(
                self,
                dst_path=old_copy / subproject_subdir,
                data=self.subproject.last_answers,
                defaults=True,
                quiet=True,
                src_path=self.subproject.template.url,
                vcs_ref=self.subproject.template.commit,
            ) as old_worker:
                old_worker.run_copy()
            # Extract diff between temporary destination and real destination
            with local.cwd(old_copy):
                self._git_initialize_repo()
                git("remote", "add", "real_dst", "file://" + str(subproject_top))
                git("fetch", "--depth=1", "real_dst", "HEAD")
                diff_cmd = git[
                    "diff-tree", f"--unified={self.context_lines}", "HEAD...FETCH_HEAD"
                ]
                try:
                    diff = diff_cmd("--inter-hunk-context=-1")
                except ProcessExecutionError:
                    print(
                        colors.warn
                        | "Make sure Git >= 2.24 is installed to improve updates.",
                        file=sys.stderr,
                    )
                    diff = diff_cmd("--inter-hunk-context=0")
            # Run pre-migration tasks
            self._execute_tasks(
                self.template.migration_tasks("before", self.subproject.template)
            )
            # Clear last answers cache to load possible answers migration, if skip_answered flag is not set
            if self.skip_answered is False:
                self.answers = AnswersMap()
                with suppress(AttributeError):
                    del self.subproject.last_answers
            # Do a normal update in final destination
            with replace(
                self,
                # Files can change due to the historical diff, and those
                # changes are not detected in this process, so it's better to
                # say nothing than lie.
                # TODO
                quiet=True,
            ) as current_worker:
                current_worker.run_copy()
                self.answers = current_worker.answers
            # Render with the same answers in an empty dir to avoid pollution
            with replace(
                self,
                dst_path=new_copy / subproject_subdir,
                data=self.answers.combined,
                defaults=True,
                quiet=True,
                src_path=self.subproject.template.url,
            ) as new_worker:
                new_worker.run_copy()
            compared = dircmp(old_copy, new_copy)
            # Try to apply cached diff into final destination
            with local.cwd(subproject_top):
                apply_cmd = git["apply", "--reject", "--exclude", self.answers_relpath]
                for skip_pattern in chain(
                    self.skip_if_exists, self.template.skip_if_exists
                ):
                    apply_cmd = apply_cmd["--exclude", skip_pattern]
                (apply_cmd << diff)(retcode=None)
                if self.conflict == "inline":
                    status = git("status", "--porcelain").strip().splitlines()
                    for line in status:
                        # Find merge rejections
                        if not (line.startswith("?? ") and line.endswith(".rej")):
                            continue
                        # FIXME Test with a file named '`â ñ"', see it fail, fix it
                        fname = line[3:-4]
                        # Undo possible non-rejected chunks
                        git("checkout", "--", fname)
                        # 3-way-merge the file directly
                        git(
                            "merge-file",
                            "-L",
                            "before updating",
                            "-L",
                            "last update",
                            "-L",
                            "after updating",
                            fname,
                            Path(old_copy) / fname,
                            Path(new_copy) / fname,
                            retcode=None,
                        )
                        # Remove rejection witness
                        Path(f"{fname}.rej").unlink()
            # Trigger recursive removal of deleted files in last template version
            _remove_old_files(subproject_top, compared)

        # Run post-migration tasks
        self._execute_tasks(
            self.template.migration_tasks("after", self.subproject.template)
        )

    def _git_initialize_repo(self):
        """Initialize a git repository in the current directory."""
        git = get_git()
        git("init", retcode=None)
        git("add", ".")
        git("config", "user.name", "Copier")
        git("config", "user.email", "copier@copier")
        # 1st commit could fail if any pre-commit hook reformats code
        # 2nd commit uses --no-verify to disable pre-commit-like checks
        git(
            "commit",
            "--allow-empty",
            "-am",
            "dumb commit 1",
            "--no-gpg-sign",
            retcode=None,
        )
        git(
            "commit",
            "--allow-empty",
            "-am",
            "dumb commit 2",
            "--no-gpg-sign",
            "--no-verify",
        )
        git("config", "--unset", "user.name")
        git("config", "--unset", "user.email")

all_exclusions: StrSeq cached property

Combine default, template and user-chosen exclusions.

answers_relpath: Path cached property

Obtain the proper relative path for the answers file.

It comes from:

1. User choice.
2. Template default.
3. Copier default.

jinja_env: SandboxedEnvironment cached property

Return a pre-configured Jinja environment.

Respects template settings.

match_exclude: Callable[[Path], bool] cached property

Get a callable to match paths against all exclusions.

match_skip: Callable[[Path], bool] cached property

Get a callable to match paths against all skip-if-exists patterns.

subproject: Subproject cached property

Get related subproject.

template: Template cached property

Get related template.

template_copy_root: Path cached property

Absolute path from where to start copying.

It points to the cloned template local abspath + the rendered subdir, if any.

__enter__()

Allow using worker as a context manager.

Source code in copier/main.py

def __enter__(self):
    """Allow using worker as a context manager."""
    return self

__exit__(type, value, traceback)

Clean up garbage files after worker usage ends.

Source code in copier/main.py

def __exit__(self, type, value, traceback):
    """Clean up garbage files after worker usage ends."""
    if value is not None:
        # exception was raised from code inside context manager:
        # try to clean up, ignoring any exception, then re-raise
        with suppress(Exception):
            self._cleanup()
        raise value
    # otherwise clean up and let any exception bubble up
    self._cleanup()

run_copy()

Generate a subproject from zero, ignoring what was in the folder.

If dst_path was missing, it will be created. Otherwise, src_path be rendered directly into it, without worrying about evolving what was there already.

See generating a project.

Source code in copier/main.py

def run_copy(self) -> None:
    """Generate a subproject from zero, ignoring what was in the folder.

    If `dst_path` was missing, it will be
    created. Otherwise, `src_path` be rendered
    directly into it, without worrying about evolving what was there
    already.

    See [generating a project][generating-a-project].
    """
    self._check_unsafe("copy")
    self._print_message(self.template.message_before_copy)
    self._ask()
    was_existing = self.subproject.local_abspath.exists()
    src_abspath = self.template_copy_root
    try:
        if not self.quiet:
            # TODO Unify printing tools
            print(
                f"\nCopying from template version {self.template.version}",
                file=sys.stderr,
            )
        self._render_folder(src_abspath)
        if not self.quiet:
            # TODO Unify printing tools
            print("")  # padding space
        self._execute_tasks(self.template.tasks)
    except Exception:
        if not was_existing and self.cleanup_on_error:
            rmtree(self.subproject.local_abspath)
        raise
    self._print_message(self.template.message_after_copy)
    if not self.quiet:
        # TODO Unify printing tools
        print("")  # padding space

run_recopy()

Update a subproject, keeping answers but discarding evolution.

Source code in copier/main.py

def run_recopy(self) -> None:
    """Update a subproject, keeping answers but discarding evolution."""
    if self.subproject.template is None:
        raise UserMessageError(
            "Cannot recopy because cannot obtain old template references "
            f"from `{self.subproject.answers_relpath}`."
        )
    with replace(self, src_path=self.subproject.template.url) as new_worker:
        return new_worker.run_copy()

run_update()

Update a subproject that was already generated.

See updating a project.

Source code in copier/main.py

def run_update(self) -> None:
    """Update a subproject that was already generated.

    See [updating a project][updating-a-project].
    """
    self._check_unsafe("update")
    # Check all you need is there
    if self.subproject.vcs != "git":
        raise UserMessageError(
            "Updating is only supported in git-tracked subprojects."
        )
    if self.subproject.is_dirty():
        raise UserMessageError(
            "Destination repository is dirty; cannot continue. "
            "Please commit or stash your local changes and retry."
        )
    if self.subproject.template is None or self.subproject.template.ref is None:
        raise UserMessageError(
            "Cannot update because cannot obtain old template references "
            f"from `{self.subproject.answers_relpath}`."
        )
    if self.template.commit is None:
        raise UserMessageError(
            "Updating is only supported in git-tracked templates."
        )
    if not self.subproject.template.version:
        raise UserMessageError(
            "Cannot update: version from last update not detected."
        )
    if not self.template.version:
        raise UserMessageError("Cannot update: version from template not detected.")
    if self.subproject.template.version > self.template.version:
        raise UserMessageError(
            f"You are downgrading from {self.subproject.template.version} to {self.template.version}. "
            "Downgrades are not supported."
        )
    if not self.overwrite:
        # Only git-tracked subprojects can be updated, so the user can
        # review the diff before committing; so we can safely avoid
        # asking for confirmation
        raise UserMessageError("Enable overwrite to update a subproject.")
    self._print_message(self.template.message_before_update)
    if not self.quiet:
        # TODO Unify printing tools
        print(
            f"Updating to template version {self.template.version}", file=sys.stderr
        )
    self._apply_update()
    self._print_message(self.template.message_after_update)

run_copy(src_path, dst_path='.', data=None, **kwargs)

Copy a template to a destination, from zero.

This is a shortcut for run_copy.

See Worker fields to understand this function's args.

Source code in copier/main.py

def run_copy(
    src_path: str,
    dst_path: StrOrPath = ".",
    data: Optional[AnyByStrDict] = None,
    **kwargs,
) -> Worker:
    """Copy a template to a destination, from zero.

    This is a shortcut for [run_copy][copier.main.Worker.run_copy].

    See [Worker][copier.main.Worker] fields to understand this function's args.
    """
    if data is not None:
        kwargs["data"] = data
    with Worker(src_path=src_path, dst_path=Path(dst_path), **kwargs) as worker:
        worker.run_copy()
    return worker

run_recopy(dst_path='.', data=None, **kwargs)

Update a subproject from its template, discarding subproject evolution.

This is a shortcut for run_recopy.

See Worker fields to understand this function's args.

Source code in copier/main.py

def run_recopy(
    dst_path: StrOrPath = ".", data: Optional[AnyByStrDict] = None, **kwargs
) -> Worker:
    """Update a subproject from its template, discarding subproject evolution.

    This is a shortcut for [run_recopy][copier.main.Worker.run_recopy].

    See [Worker][copier.main.Worker] fields to understand this function's args.
    """
    if data is not None:
        kwargs["data"] = data
    with Worker(dst_path=Path(dst_path), **kwargs) as worker:
        worker.run_recopy()
    return worker

run_update(dst_path='.', data=None, **kwargs)

Update a subproject, from its template.

This is a shortcut for run_update.

See Worker fields to understand this function's args.

Source code in copier/main.py

def run_update(
    dst_path: StrOrPath = ".",
    data: Optional[AnyByStrDict] = None,
    **kwargs,
) -> Worker:
    """Update a subproject, from its template.

    This is a shortcut for [run_update][copier.main.Worker.run_update].

    See [Worker][copier.main.Worker] fields to understand this function's args.
    """
    if data is not None:
        kwargs["data"] = data
    with Worker(dst_path=Path(dst_path), **kwargs) as worker:
        worker.run_update()
    return worker