Fix the --system without --deploy flag bug (#6297)

* Fix the --system without --deploy flag bug
* add news fragment

news/6295.bugfix.rst

@@ -0,0 +1 @@
+Fix regression of ``2024.3.0`` when using the ``--system`` flag without ``--deploy`` flag.

pipenv/routines/install.py

@@ -158,18 +158,19 @@ def handle_lockfile(
                     style="red",
                 )
                 raise exceptions.DeployException
-            handle_outdated_lockfile(
-                project,
-                packages,
-                old_hash=old_hash,
-                new_hash=new_hash,
-                system=system,
-                allow_global=allow_global,
-                skip_lock=skip_lock,
-                pre=pre,
-                pypi_mirror=pypi_mirror,
-                categories=categories,
-            )
+            elif not system:
+                handle_outdated_lockfile(
+                    project,
+                    packages,
+                    old_hash=old_hash,
+                    new_hash=new_hash,
+                    system=system,
+                    allow_global=allow_global,
+                    skip_lock=skip_lock,
+                    pre=pre,
+                    pypi_mirror=pypi_mirror,
+                    categories=categories,
+                )
     elif not project.lockfile_exists and not skip_lock:
         handle_missing_lockfile(project, system, allow_global, pre, pypi_mirror)
 
@@ -305,7 +306,7 @@ def do_install(
         categories=pipfile_categories,
         skip_lock=skip_lock,
     )
-    if not deploy:
+    if not (deploy or system):
         new_packages, _ = handle_new_packages(
             project,
             packages,

tests/integration/test_install_basic.py

@@ -376,6 +376,22 @@ def test_system_and_deploy_work(pipenv_instance_private_pypi):
         assert c.returncode == 0
 
 
+
+@pytest.mark.cli
+@pytest.mark.deploy
+@pytest.mark.system
+def test_system_works(pipenv_instance_pypi):
+    with pipenv_instance_pypi() as p:
+        c = p.pipenv("install urllib3")
+        assert c.returncode == 0
+        c = p.pipenv("--rm")
+        assert c.returncode == 0
+        c = subprocess_run(["virtualenv", ".venv"])
+        assert c.returncode == 0
+        c = p.pipenv("install --system")
+        assert c.returncode == 0
+
+
 @pytest.mark.basic
 @pytest.mark.install
 def test_install_creates_pipfile(pipenv_instance_pypi):