fix: do not immediately fail if git is not available

Copier has lots of git-related stuff, but it also has features that work without it. It is now a lazy requirement.

Fixes #312

Author: astrojuanlu

copier/main.py

@@ -31,7 +31,6 @@
 from pathspec import PathSpec
 from plumbum import ProcessExecutionError, colors
 from plumbum.cli.terminal import ask
-from plumbum.cmd import git
 from plumbum.machines import local
 from pydantic import ConfigDict, PositiveInt
 from pydantic.dataclasses import dataclass
@@ -57,6 +56,7 @@
     StrSeq,
 )
 from .user_data import DEFAULT_DATA, AnswersMap, Question
+from .vcs import get_git
 
 
 @dataclass(config=ConfigDict(extra="forbid"))
@@ -815,6 +815,7 @@ def run_update(self) -> None:
         self._print_message(self.template.message_after_update)
 
     def _apply_update(self):
+        git = get_git()
         subproject_top = Path(
             git(
                 "-C",
@@ -931,6 +932,7 @@ def _apply_update(self):
 
     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")

copier/subproject.py

@@ -9,13 +9,12 @@
 from typing import Callable, List, Optional
 
 import yaml
-from plumbum.cmd import git
 from plumbum.machines import local
 from pydantic.dataclasses import dataclass
 
 from .template import Template
 from .types import AbsolutePath, AnyByStrDict, VCSTypes
-from .vcs import is_in_git_repo
+from .vcs import get_git, is_in_git_repo
 
 
 @dataclass
@@ -42,7 +41,7 @@ def is_dirty(self) -> bool:
         """
         if self.vcs == "git":
             with local.cwd(self.local_abspath):
-                return bool(git("status", "--porcelain").strip())
+                return bool(get_git()("status", "--porcelain").strip())
         return False
 
     def _cleanup(self):

copier/template.py

@@ -14,7 +14,6 @@
 import yaml
 from funcy import lflatten
 from packaging.version import Version, parse
-from plumbum.cmd import git
 from plumbum.machines import local
 from pydantic.dataclasses import dataclass
 from yamlinclude import YamlIncludeConstructor
@@ -28,7 +27,7 @@
 )
 from .tools import copier_version, handle_remove_readonly
 from .types import AnyByStrDict, Env, OptStr, StrSeq, Union, VCSTypes
-from .vcs import checkout_latest_tag, clone, get_repo
+from .vcs import checkout_latest_tag, clone, get_git, get_repo
 
 # Default list of files in the template to exclude from the rendered project
 DEFAULT_EXCLUDE: Tuple[str, ...] = (
@@ -249,13 +248,13 @@ def commit(self) -> OptStr:
         """If the template is VCS-tracked, get its commit description."""
         if self.vcs == "git":
             with local.cwd(self.local_abspath):
-                return git("describe", "--tags", "--always").strip()
+                return get_git()("describe", "--tags", "--always").strip()
 
     @cached_property
     def commit_hash(self) -> OptStr:
         """If the template is VCS-tracked, get its commit full hash."""
         if self.vcs == "git":
-            return git("-C", self.local_abspath, "rev-parse", "HEAD").strip()
+            return get_git()("-C", self.local_abspath, "rev-parse", "HEAD").strip()
 
     @cached_property
     def config_data(self) -> AnyByStrDict:

copier/vcs.py

@@ -10,14 +10,24 @@
 from packaging import version
 from packaging.version import InvalidVersion, Version
 from plumbum import TF, ProcessExecutionError, colors, local
-from plumbum.cmd import git
 
 from .errors import DirtyLocalWarning, ShallowCloneWarning
 from .types import OptBool, OptStr, StrOrPath
 
+
+def get_git():
+    """Gets `git` command, or fails if it's not available"""
+    return local["git"]
+
+
+def get_git_version():
+    git = get_git()
+
+    return Version(re.findall(r"\d+\.\d+\.\d+", git("version"))[0])
+
+
 GIT_PREFIX = ("git@", "git://", "git+", "https://github.com/", "https://gitlab.com/")
 GIT_POSTFIX = ".git"
-GIT_VERSION = Version(re.findall(r"\d+\.\d+\.\d+", git("version"))[0])
 REPLACEMENTS = (
     (re.compile(r"^gh:/?(.*\.git)$"), r"https://github.com/\1"),
     (re.compile(r"^gh:/?(.*)$"), r"https://github.com/\1.git"),
@@ -30,15 +40,15 @@ def is_git_repo_root(path: StrOrPath) -> bool:
     """Indicate if a given path is a git repo root directory."""
     try:
         with local.cwd(Path(path, ".git")):
-            return git("rev-parse", "--is-inside-git-dir").strip() == "true"
+            return get_git()("rev-parse", "--is-inside-git-dir").strip() == "true"
     except OSError:
         return False
 
 
 def is_in_git_repo(path: StrOrPath) -> bool:
     """Indicate if a given path is in a git repo directory."""
     try:
-        git("-C", path, "rev-parse", "--show-toplevel")
+        get_git()("-C", path, "rev-parse", "--show-toplevel")
         return True
     except (OSError, ProcessExecutionError):
         return False
@@ -47,7 +57,10 @@ def is_in_git_repo(path: StrOrPath) -> bool:
 def is_git_shallow_repo(path: StrOrPath) -> bool:
     """Indicate if a given path is a git shallow repo directory."""
     try:
-        return git("-C", path, "rev-parse", "--is-shallow-repository").strip() == "true"
+        return (
+            get_git()("-C", path, "rev-parse", "--is-shallow-repository").strip()
+            == "true"
+        )
     except (OSError, ProcessExecutionError):
         return False
 
@@ -58,8 +71,8 @@ def is_git_bundle(path: Path) -> bool:
         path = path.resolve()
     with TemporaryDirectory(prefix=f"{__name__}.is_git_bundle.") as dirname:
         with local.cwd(dirname):
-            git("init")
-            return bool(git["bundle", "verify", path] & TF)
+            get_git()("init")
+            return bool(get_git()["bundle", "verify", path] & TF)
 
 
 def get_repo(url: str) -> OptStr:
@@ -107,6 +120,7 @@ def checkout_latest_tag(local_repo: StrOrPath, use_prereleases: OptBool = False)
         use_prereleases:
             If `False`, skip prerelease git tags.
     """
+    git = get_git()
     with local.cwd(local_repo):
         all_tags = filter(valid_version, git("tag").split())
         if not use_prereleases:
@@ -140,10 +154,12 @@ def clone(url: str, ref: OptStr = None) -> str:
         ref:
             Reference to checkout. For Git repos, defaults to `HEAD`.
     """
+    git = get_git()
+    git_version = get_git_version()
     location = mkdtemp(prefix=f"{__name__}.clone.")
     _clone = git["clone", "--no-checkout", url, location]
     # Faster clones if possible
-    if GIT_VERSION >= Version("2.27"):
+    if git_version >= Version("2.27"):
         url_match = re.match("(file://)?(.*)", url)
         if url_match is not None:
             file_url = url_match.groups()[-1]

tests/test_vcs.py

@@ -11,7 +11,7 @@
 
 from copier import Worker, run_copy, run_update
 from copier.errors import ShallowCloneWarning
-from copier.vcs import GIT_VERSION, checkout_latest_tag, clone, get_repo
+from copier.vcs import checkout_latest_tag, clone, get_git_version, get_repo
 
 
 def test_get_repo() -> None:
@@ -93,7 +93,7 @@ def test_shallow_clone(tmp_path: Path, recwarn: pytest.WarningsRecorder) -> None
     git("clone", "--depth=2", "https://github.com/copier-org/autopretty.git", src_path)
     assert Path(src_path, "README.md").exists()
 
-    if GIT_VERSION >= Version("2.27"):
+    if get_git_version() >= Version("2.27"):
         with pytest.warns(ShallowCloneWarning):
             local_tmp = clone(str(src_path))
     else: