Merge pull request #1720 from EliahKagan/nopathmod

Never modify sys.path

Author: Byron

README.md

@@ -97,6 +97,20 @@ pip install -e ".[test]"
 
 In the less common case that you do not want to install test dependencies, `pip install -e .` can be used instead.
 
+#### With editable *dependencies* (not preferred, and rarely needed)
+
+In rare cases, you may want to work on GitPython and one or both of its [gitdb](https://github.com/gitpython-developers/gitdb) and [smmap](https://github.com/gitpython-developers/smmap) dependencies at the same time, with changes in your local working copy of gitdb or smmap immediatley reflected in the behavior of your local working copy of GitPython. This can be done by making editable installations of those dependencies in the same virtual environment where you install GitPython.
+
+If you want to do that *and* you want the versions in GitPython's git submodules to be used, then pass `-e git/ext/gitdb` and/or `-e git/ext/gitdb/gitdb/ext/smmap` to `pip install`. This can be done in any order, and in separate `pip install` commands or the same one, so long as `-e` appears before *each* path. For example, you can install GitPython, gitdb, and smmap editably in the currently active virtual environment this way:
+
+```bash
+pip install -e ".[test]" -e git/ext/gitdb -e git/ext/gitdb/gitdb/ext/smmap
+```
+
+The submodules must have been cloned for that to work, but that will already be the case if you have run `./init-tests-after-clone.sh`. You can use `pip list` to check which packages are installed editably and which are installed normally.
+
+To reiterate, this approach should only rarely be used. For most development it is preferable to allow the gitdb and smmap dependencices to be retrieved automatically from PyPI in their latest stable packaged versions.
+
 ### Limitations
 
 #### Leakage of System Resources

git/__init__.py

@@ -6,38 +6,11 @@
 # flake8: noqa
 # @PydevCodeAnalysisIgnore
 from git.exc import *  # @NoMove @IgnorePep8
-import os
-import os.path as osp
-import sys
-
 from typing import List, Optional, Sequence, Tuple, Union, TYPE_CHECKING
 from git.types import PathLike
 
 __version__ = "git"
 
-
-# { Initialization
-def _init_externals() -> None:
-    """Initialize external projects by putting them into the path"""
-    if __version__ == "git" and "PYOXIDIZER" not in os.environ:
-        sys.path.insert(1, osp.join(osp.dirname(__file__), "ext", "gitdb"))
-
-    try:
-        import gitdb
-    except ImportError as e:
-        raise ImportError("'gitdb' could not be found in your PYTHONPATH") from e
-    # END verify import
-
-
-# } END initialization
-
-
-#################
-_init_externals()
-#################
-
-# { Imports
-
 from gitdb.util import to_hex_sha
 
 try:
@@ -62,8 +35,6 @@ def _init_externals() -> None:
 except GitError as _exc:
     raise ImportError("%s: %s" % (_exc.__class__.__name__, _exc)) from _exc
 
-# } END imports
-
 # __all__ must be statically defined by py.typed support
 # __all__ = [name for name, obj in locals().items() if not (name.startswith("_") or inspect.ismodule(obj))]
 __all__ = [

test/test_installation.py

@@ -25,6 +25,7 @@ def setUp_venv(self, rw_dir):
     @with_rw_directory
     def test_installation(self, rw_dir):
         self.setUp_venv(rw_dir)
+
         result = subprocess.run(
             [self.pip, "install", "."],
             stdout=subprocess.PIPE,
@@ -35,12 +36,32 @@ def test_installation(self, rw_dir):
             result.returncode,
             msg=result.stderr or result.stdout or "Can't install project",
         )
-        result = subprocess.run([self.python, "-c", "import git"], stdout=subprocess.PIPE, cwd=self.sources)
+
+        result = subprocess.run(
+            [self.python, "-c", "import git"],
+            stdout=subprocess.PIPE,
+            cwd=self.sources,
+        )
         self.assertEqual(
             0,
             result.returncode,
             msg=result.stderr or result.stdout or "Selftest failed",
         )
+
+        result = subprocess.run(
+            [self.python, "-c", "import gitdb; import smmap"],
+            stdout=subprocess.PIPE,
+            cwd=self.sources,
+        )
+        self.assertEqual(
+            0,
+            result.returncode,
+            msg=result.stderr or result.stdout or "Dependencies not installed",
+        )
+
+        # Even IF gitdb or any other dependency is supplied during development
+        # by inserting its location into PYTHONPATH or otherwise patched into
+        # sys.path, make sure it is not wrongly inserted as the *first* entry.
         result = subprocess.run(
             [self.python, "-c", "import sys;import git; print(sys.path)"],
             stdout=subprocess.PIPE,
@@ -53,4 +74,3 @@ def test_installation(self, rw_dir):
             syspath[0],
             msg="Failed to follow the conventions for https://docs.python.org/3/library/sys.html#sys.path",
         )
-        self.assertTrue(syspath[1].endswith("gitdb"), msg="Failed to add gitdb to sys.path")