Fix relative discovery (#1734)

Signed-off-by: Bernat Gabor <bgabor8@bloomberg.net>

docs/changelog/1734.bugfix.rst

@@ -0,0 +1 @@
+Fix relative path discovery of interpreters - by :user:`gaborbernat`.

src/virtualenv/discovery/py_info.py

@@ -229,8 +229,8 @@ def clear_cache(cls, app_data):
 
     def satisfies(self, spec, impl_must_match):
         """check if a given specification can be satisfied by the this python interpreter instance"""
-        if self.executable == spec.path:  # if the path is a our own executable path we're done
-            return True
+        if spec.path and self.executable == os.path.abspath(spec.path):
+            return True  # if the path is a our own executable path we're done
 
         if spec.path is not None:  # if path set, and is not our original executable name, this does not match
             root, _ = os.path.splitext(os.path.basename(self.original_executable))

tests/unit/discovery/test_discovery.py

@@ -44,3 +44,12 @@ def test_discovery_via_path_not_found(tmp_path, monkeypatch):
     monkeypatch.setenv(str("PATH"), str(tmp_path))
     interpreter = get_interpreter(uuid4().hex)
     assert interpreter is None
+
+
+def test_relative_path(tmp_path, session_app_data, monkeypatch):
+    sys_executable = Path(PythonInfo.current_system(app_data=session_app_data).system_executable)
+    cwd = sys_executable.parents[1]
+    monkeypatch.chdir(str(cwd))
+    relative = str(sys_executable.relative_to(cwd))
+    result = get_interpreter(relative, session_app_data)
+    assert result is not None