Revert back to build isolation by default; support extra-pip-args on sync command.

pipenv/cli/options.py

@@ -561,6 +561,7 @@ def install_base_options(f):
     f = common_options(f)
     f = pre_option(f)
     f = keep_outdated_option(f)
+    f = extra_pip_args(f)
     return f
 
 
@@ -597,7 +598,6 @@ def install_options(f):
     f = ignore_pipfile_option(f)
     f = editable_option(f)
     f = package_arg(f)
-    f = extra_pip_args(f)
     return f
 
 

pipenv/core.py

@@ -1340,7 +1340,7 @@ def get_pip_args(
     verbose: bool = False,
     upgrade: bool = False,
     require_hashes: bool = False,
-    no_build_isolation: bool = True,
+    no_build_isolation: bool = False,
     no_use_pep517: bool = False,
     no_deps: bool = False,
     selective_upgrade: bool = False,

tests/integration/test_install_categories.py

@@ -69,5 +69,5 @@ six = "*"
         assert "testpipenv" in p.lockfile["default"]
         assert "testpipenv" not in p.lockfile["prereq"]
         assert "six" in p.lockfile["prereq"]
-        c = p.pipenv('sync --categories="prereq packages" -v')
+        c = p.pipenv('sync --categories="prereq packages" --extra-pip-args="--no-build-isolation" -v')
         assert c.returncode == 0