Improve PEX_PATH handling in pex.py

pex/pex.py

@@ -68,11 +68,15 @@ def _activate(self):
 
       # set up the local .pex environment
       pex_info = self._pex_info.copy()
+      pex_info_pex_path = pex_info.pex_path
+      overrides_pex_path = self._pex_info_overrides.pex_path
       pex_info.update(self._pex_info_overrides)
+      pex_info.pex_path = ":".join(filter(None, [pex_info_pex_path, overrides_pex_path]))
       self._envs.append(PEXEnvironment(self._pex, pex_info))
-
+      # by this point, pex_info.pex_path will have a single pex path merged from pex_path
+      # in PEX-INFO and pex_path set in the environment
       if pex_info.pex_path:
-        # set up other environments as specified in PEX_PATH
+        # set up other environments as specified in pex_path
         for pex_path in filter(None, pex_info.pex_path.split(os.pathsep)):
           pex_info = PexInfo.from_pex(pex_path)
           pex_info.update(self._pex_info_overrides)
@@ -279,7 +283,7 @@ def patch_all(path, path_importer_cache, modules):
         sys.path[:], sys.path_importer_cache.copy(), sys.modules.copy())
     new_sys_path, new_sys_path_importer_cache, new_sys_modules = self.minimum_sys(inherit_path)
 
-    new_sys_path.extend(filter(None, self._vars.PEX_PATH.split(os.pathsep)))
+    new_sys_path.extend(self._merge_split(self._pex_info.pex_path, self._vars.PEX_PATH))
 
     patch_all(new_sys_path, new_sys_path_importer_cache, new_sys_modules)
     yield
@@ -490,6 +494,10 @@ def cmdline(self, args=()):
     cmds.extend(args)
     return cmds
 
+  def _merge_split(self, *paths):
+    merged_paths = ":".join(filter(None, paths))
+    return filter(None, merged_paths.split(':'))
+
   def run(self, args=(), with_chroot=False, blocking=True, setsid=False, **kwargs):
     """Run the PythonEnvironment in an interpreter in a subprocess.
 

tests/test_integration.py

@@ -278,3 +278,52 @@ def test_pex_path_arg():
     stdout, rc = run_simple_pex(pex_out_path, [test_file_path])
     assert rc == 0
     assert stdout == b'Success!\n'
+
+
+def test_pex_path_in_pex_info_and_env():
+  with temporary_dir() as output_dir:
+
+    # create 2 pex files for PEX-INFO pex_path
+    pex1_path = os.path.join(output_dir, 'pex1.pex')
+    res1 = run_pex_command(['--disable-cache', 'requests', '-o', pex1_path])
+    res1.assert_success()
+    pex2_path = os.path.join(output_dir, 'pex2.pex')
+    res2 = run_pex_command(['--disable-cache', 'flask', '-o', pex2_path])
+    res2.assert_success()
+    pex_path = ':'.join(os.path.join(output_dir, name) for name in ('pex1.pex', 'pex2.pex'))
+
+    # create a pex for environment PEX_PATH
+    pex3_path = os.path.join(output_dir, 'pex3.pex')
+    res3 = run_pex_command(['--disable-cache', 'sqlalchemy', '-o', pex3_path])
+    res3.assert_success()
+    env_pex_path = os.path.join(output_dir, 'pex3.pex')
+
+    # parameterize the pex arg for test.py
+    pex_out_path = os.path.join(output_dir, 'out.pex')
+    # create test file test.py that attempts to import modules from pex1/pex2
+    test_file_path = os.path.join(output_dir, 'test.py')
+    with open(test_file_path, 'w') as fh:
+      fh.write(dedent('''
+        import requests
+        import flask
+        import sqlalchemy
+        import sys
+        import os
+        import subprocess
+        print('Success!')
+        '''))
+
+    # build out.pex composed from pex1/pex1
+    run_pex_command(['--disable-cache',
+      '--pex-path={}'.format(pex_path),
+      'wheel',
+      '-o', pex_out_path])
+
+    # load secondary PEX_PATH
+    env = os.environ.copy()
+    env['PEX_PATH'] = env_pex_path
+
+    # run test.py with composite env
+    stdout, rc = run_simple_pex(pex_out_path, [test_file_path], env=env)
+    assert rc == 0
+    assert stdout == b'Success!\n'