fix system executable discovery

docs/changelog/1552.bugfix.rst

@@ -0,0 +1 @@
+Virtual environments created via relative path on Windows creates bad console executables - by :user:`gaborbernat`.

docs/changelog/1553.bugfix.rst

@@ -0,0 +1,2 @@
+Seems sometimes venvs created set their base executable to themselves; we accept these without question, so we handle
+virtual environments as system pythons causing issues - by :user:`gaborbernat`.

src/virtualenv/create/creator.py

@@ -131,7 +131,7 @@ def non_write_able(dest, value):
             # pre 3.6 resolve is always strict, aka must exists, sidestep by using os.path operation
             dest = Path(os.path.realpath(raw_value))
         else:
-            dest = value.resolve()
+            dest = value.resolve().absolute()  # on Windows absolute does not imply resolve so use both
         value = dest
         while dest:
             if dest.exists():

src/virtualenv/discovery/py_info.py

@@ -96,7 +96,8 @@ def _fast_get_system_executable(self):
             if self.real_prefix is None:
                 base_executable = getattr(sys, "_base_executable", None)  # some platforms may set this to help us
                 if base_executable is not None:  # use the saved system executable if present
-                    return base_executable
+                    if sys.executable != base_executable:  # we know we're in a virtual environment, cannot be us
+                        return base_executable
             return None  # in this case we just can't tell easily without poking around FS and calling them, bail
         # if we're not in a virtual environment, this is already a system python, so return the original executable
         # note we must choose the original and not the pure executable as shim scripts might throw us off

tests/unit/create/test_creator.py

@@ -14,7 +14,7 @@
 import six
 
 from virtualenv.__main__ import run
-from virtualenv.create.creator import DEBUG_SCRIPT, get_env_debug_info
+from virtualenv.create.creator import DEBUG_SCRIPT, Creator, get_env_debug_info
 from virtualenv.discovery.builtin import get_interpreter
 from virtualenv.discovery.py_info import PythonInfo
 from virtualenv.info import IS_PYPY, fs_supports_symlink
@@ -291,3 +291,9 @@ def create(count):
         thread.start()
     for thread in threads:
         thread.join()
+
+
+def test_creator_input_passed_is_abs(tmp_path, monkeypatch):
+    monkeypatch.chdir(tmp_path)
+    result = Creator.validate_dest("venv")
+    assert str(result) == str(tmp_path / "venv")