Fix search of python3 binary on macOS. Closes #247.

Allow search of multiple CLI names for a package manager.

Author: kdeldycke

changelog.rst

@@ -9,6 +9,8 @@ Changelog
 
 * [xbar] Add new ``Submenu layout`` boolean option in xbar plugin UI.
 * [xbar] Rename ``XBAR_MPM_SUBMENU`` environment variable to ``VAR_SUBMENU_lAYOUT``.
+* [mpm] Allow search of multiple CLI names for a package manager.
+* [pip] Fix search of `python3` binary on macOS. Closes #247.
 
 
 `4.0.0 (2021-04-27) <https://github.com/kdeldycke/meta-package-manager/compare/v3.6.0...v4.0.0>`_

meta_package_manager/base.py

@@ -116,12 +116,16 @@ def name(cls):
         return cls.__name__
 
     @classproperty
-    def cli_name(cls):
-        """Package manager's CLI name.
+    def cli_names(cls):
+        """List of CLI names the package manager is known as.
+
+        The supported CLI names are ordered by priority. This is used for example to
+        help out the search of the right binary in the case of the python3/python2
+        transition.
 
         Is derived by default from the manager's ID.
         """
-        return cls.id
+        return [cls.id]
 
     @classproperty
     def virtual(cls):
@@ -130,23 +134,31 @@ def virtual(cls):
         Virtual package manager are just skeleton classes used to factorize
         code among managers of the same family.
         """
-        return cls.__name__ == "PackageManager" or not cls.cli_name
+        return cls.__name__ == "PackageManager" or not cls.cli_names
 
     @cachedproperty
     def cli_path(self):
         """Fully qualified path to the package manager CLI.
 
-        Automaticaly search the location of the CLI in the system. Only checks
-        if the file exists. Its executability will be assessed later. See the
-        ``self.executable`` method below.
+        Automaticaly search the location of the CLI in the system. Try multiple CLI
+        names within several system path.
+
+        Only checks if the file exists. Its executability will be assessed later. See
+        the ``self.executable`` method below.
 
-        Returns `None` if CLI is not found or is not a file.
+        Returns `None` if no CLI was found or those found were not a file.
         """
         # Check if the path exist in any of the environment locations.
         env_path = ":".join(self.cli_search_path + [os.getenv("PATH")])
-        cli_path = which(self.cli_name, mode=os.F_OK, path=env_path)
+
+        # Search for multiple CLI names.
+        for name in self.cli_names:
+            cli_path = which(name, mode=os.F_OK, path=env_path)
+            if cli_path:
+                break
+            logger.debug(f"{name!r} CLI not found.")
+
         if not cli_path:
-            logger.debug(f"{self.cli_name} CLI not found.")
             return
 
         # Check if path exist and is a file.
@@ -158,7 +170,7 @@ def cli_path(self):
         elif not cli_path.is_file():
             logger.warning(f"{cli_path} is not a file.")
         else:
-            logger.debug(f"CLI found at {cli_path}")
+            logger.debug(f"{name!r} CLI found at {cli_path}")
 
         return cli_path
 

meta_package_manager/cli.py

@@ -375,7 +375,9 @@ def managers(ctx):
         # Build up the CLI path column content.
         cli_infos = "{}  {}".format(
             OK if manager.cli_path else KO,
-            manager.cli_path if manager.cli_path else f"{manager.cli_name!r} not found",
+            manager.cli_path
+            if manager.cli_path
+            else f"no {', '.join(manager.cli_names)} found",
         )
 
         # Build up the version column content.

meta_package_manager/managers/__init__.py

@@ -37,7 +37,7 @@ def pool():
     Is considered valid package manager, definitions classes which:
         1 - are sub-classes of PackageManager, and
         2 - are located in files at the same level or below this one, and
-        3 - are not virtual (i.e. have a non null cli_name property).
+        3 - are not virtual (i.e. have a non null `cli_names` property).
 
     Returns an `OrderedDict` sorted by manager's ID.
     """

meta_package_manager/managers/homebrew.py

@@ -44,7 +44,7 @@ class Homebrew(PackageManager):
     requirement = "2.7.0"
 
     # Declare this manager as virtual, i.e. not tied to a real CLI.
-    cli_name = None
+    cli_names = None
 
     def get_version(self):
         """Fetch version from ``brew --version`` output.
@@ -472,7 +472,7 @@ def cleanup(self):
 class Brew(Homebrew):
 
     name = "Homebrew Formulae"
-    cli_name = "brew"
+    cli_names = ["brew"]
 
     global_args = ["--formula"]
 
@@ -482,6 +482,6 @@ class Cask(Homebrew):
     # Casks are only available on macOS, not Linux.
     platforms = frozenset([MACOS])
     name = "Homebrew Cask"
-    cli_name = "brew"
+    cli_names = ["brew"]
 
     global_args = ["--cask"]

meta_package_manager/managers/pip.py

@@ -26,19 +26,20 @@
 
 class Pip(PackageManager):
 
-    """We will use system's default Python to call out ``pip`` as a module.
+    """We will use the Python binary to call out ``pip`` as a module instead of a CLI.
 
     This is a more robust way of managing packages: "if you're on Windows there
-    is an added benefit to using python -m pip as it lets pip update itself."
+    is an added benefit to using `python -m pip` as it lets `pip` update itself."
     Source: https://snarky.ca/why-you-should-use-python-m-pip/
     """
 
     platforms = frozenset([MACOS, LINUX, WINDOWS])
 
     requirement = "10.0.0"
 
-    # We will use system's default python to call out pip as a module.
-    cli_name = "python"
+    # Targets `python3` CLI first to allow for some systems (like macOS) to keep the
+    # default `python` CLI tied to the Python 2.x ecosystem.
+    cli_names = ["python3", "python"]
 
     global_args = [
         "-m",

meta_package_manager/tests/test_managers.py

@@ -73,13 +73,15 @@ def test_platforms():
         assert manager.platforms.issubset(OS_DEFINITIONS)
 
 
-def test_cli_name_type():
+def test_cli_names_type():
     """Check the pointed CLI name and path are file-system compatible."""
     for manager in pool().values():
-        assert manager.cli_name
-        assert isinstance(manager.cli_name, str)
-        assert manager.cli_name.isalnum()
-        assert PurePath(manager.cli_name).name == manager.cli_name
+        assert manager.cli_names
+        assert isinstance(manager.cli_names, list)
+        for name in manager.cli_names:
+            assert isinstance(name, str)
+            assert name.isalnum()
+            assert PurePath(name).name == name
 
 
 def test_virtual():