drop support for pip <19.0.0

src/poetry/installation/executor.py

@@ -696,15 +696,6 @@ def _install_directory_without_wheel_installer(
                 package_poetry = Factory().create_poetry(pyproject.file.path.parent)
 
         if package_poetry is not None:
-            # Even if there is a build system specified
-            # some versions of pip (< 19.0.0) don't understand it
-            # so we need to check the version of pip to know
-            # if we can rely on the build system
-            legacy_pip = (
-                self._env.pip_version
-                < self._env.pip_version.__class__.from_parts(19, 0, 0)
-            )
-
             builder: Builder
             if package.develop and not package_poetry.package.build_script:
                 from poetry.masonry.builders.editable import EditableBuilder
@@ -716,13 +707,10 @@ def _install_directory_without_wheel_installer(
                 builder.build()
 
                 return 0
-            elif legacy_pip or package_poetry.package.build_script:
+
+            if package_poetry.package.build_script:
                 from poetry.core.masonry.builders.sdist import SdistBuilder
 
-                # We need to rely on creating a temporary setup.py
-                # file since the version of pip does not support
-                # build-systems
-                # We also need it for non-PEP-517 packages
                 builder = SdistBuilder(package_poetry)
                 with builder.setup_py():
                     return self.pip_install(req, upgrade=True, editable=package.develop)

src/poetry/utils/env/base_env.py

@@ -21,7 +21,6 @@
 
 if TYPE_CHECKING:
     from packaging.tags import Tag
-    from poetry.core.constraints.version import Version
     from poetry.core.version.markers import BaseMarker
     from virtualenv.seed.wheels.util import Wheel
 
@@ -54,7 +53,6 @@ def __init__(self, path: Path, base: Path | None = None) -> None:
         self._base = base or path
 
         self._marker_env: dict[str, Any] | None = None
-        self._pip_version: Version | None = None
         self._site_packages: SitePackages | None = None
         self._paths: dict[str, str] | None = None
         self._supported_tags: list[Tag] | None = None
@@ -170,13 +168,6 @@ def platform(self) -> str:
     def os(self) -> str:
         return os.name
 
-    @property
-    def pip_version(self) -> Version:
-        if self._pip_version is None:
-            self._pip_version = self.get_pip_version()
-
-        return self._pip_version
-
     @property
     def site_packages(self) -> SitePackages:
         if self._site_packages is None:
@@ -288,9 +279,6 @@ def get_pip_command(self, embedded: bool = False) -> list[str]:
     def get_supported_tags(self) -> list[Tag]:
         raise NotImplementedError()
 
-    def get_pip_version(self) -> Version:
-        raise NotImplementedError()
-
     def get_paths(self) -> dict[str, str]:
         raise NotImplementedError()
 

src/poetry/utils/env/mock_env.py

@@ -3,8 +3,6 @@
 from typing import TYPE_CHECKING
 from typing import Any
 
-from poetry.core.constraints.version import Version
-
 from poetry.utils.env.null_env import NullEnv
 
 
@@ -22,7 +20,6 @@ def __init__(
         platform_machine: str = "amd64",
         os_name: str = "posix",
         is_venv: bool = False,
-        pip_version: str = "19.1",
         sys_path: list[str] | None = None,
         marker_env: dict[str, Any] | None = None,
         supported_tags: list[Tag] | None = None,
@@ -36,7 +33,6 @@ def __init__(
         self._platform_machine = platform_machine
         self._os_name = os_name
         self._is_venv = is_venv
-        self._pip_version: Version = Version.parse(pip_version)
         self._sys_path = sys_path
         self._mock_marker_env = marker_env
         self._supported_tags = supported_tags
@@ -53,10 +49,6 @@ def platform_machine(self) -> str:
     def os(self) -> str:
         return self._os_name
 
-    @property
-    def pip_version(self) -> Version:
-        return self._pip_version
-
     @property
     def sys_path(self) -> list[str]:
         if self._sys_path is None:

src/poetry/utils/env/system_env.py

@@ -13,7 +13,6 @@
 from packaging.tags import interpreter_name
 from packaging.tags import interpreter_version
 from packaging.tags import sys_tags
-from poetry.core.constraints.version import Version
 
 from poetry.utils.env.base_env import Env
 
@@ -81,11 +80,6 @@ def get_marker_env(self) -> dict[str, Any]:
             "interpreter_version": interpreter_version(),
         }
 
-    def get_pip_version(self) -> Version:
-        from pip import __version__
-
-        return Version.parse(__version__)
-
     def is_venv(self) -> bool:
         return self._path != self._base
 

src/poetry/utils/env/virtual_env.py

@@ -13,7 +13,6 @@
 from typing import Any
 
 from packaging.tags import Tag
-from poetry.core.constraints.version import Version
 
 from poetry.utils.env.base_env import Env
 from poetry.utils.env.script_strings import GET_BASE_PREFIX
@@ -72,16 +71,6 @@ def get_marker_env(self) -> dict[str, Any]:
         env: dict[str, Any] = json.loads(output)
         return env
 
-    def get_pip_version(self) -> Version:
-        output = self.run_pip("--version")
-        output = output.strip()
-
-        m = re.match("pip (.+?)(?: from .+)?$", output)
-        if not m:
-            return Version.parse("0.0")
-
-        return Version.parse(m.group(1))
-
     def get_paths(self) -> dict[str, str]:
         output = self.run_python_script(GET_PATHS)
         paths: dict[str, str] = json.loads(output)

tests/utils/env/test_env.py

@@ -2,6 +2,7 @@
 
 import contextlib
 import os
+import re
 import site
 import subprocess
 import sys
@@ -82,9 +83,8 @@ def test_env_commands_with_spaces_in_their_arg_work_as_expected(
     venv_path = tmp_path / "Virtual Env"
     manager.build_venv(venv_path)
     venv = VirtualEnv(venv_path)
-    assert venv.run("python", str(venv.pip), "--version").startswith(
-        f"pip {venv.pip_version} from "
-    )
+    output = venv.run("python", str(venv.pip), "--version")
+    assert re.match(r"pip \S+ from", output)
 
 
 def test_env_get_supported_tags_matches_inside_virtualenv(