[GH-527] os.environ was not inherited with Java posix backend

Author: timfel

graalpython/com.oracle.graal.python.test/src/tests/test_subprocess.py

@@ -162,6 +162,21 @@ def test_java_asserts(self):
                 result = subprocess.run([sys.executable, "-c", "import __graalpython__; not __graalpython__.java_assert()"])
             assert result.returncode == 0
 
+    def test_subprocess_inherits_environ(self):
+        import os
+        import subprocess
+        prev = os.environ.get("FOOBAR")
+        try:
+            expected_value = f"42{prev}".strip()
+            os.environ["FOOBAR"] = expected_value
+            out = subprocess.check_output([sys.executable, '-c', "import os; print(os.environ['FOOBAR'])"]).decode().strip()
+            assert out == expected_value, f"{out!r} != {expected_value!r}"
+        finally:
+            if prev:
+                os.environ["FOOBAR"] = prev
+            else:
+                del os.environ["FOOBAR"]
+
     @unittest.skipUnless(sys.implementation.name == 'graalpy', "GraalPy-specific test")
     @unittest.skipIf(sys.platform == 'win32', "TODO the cmd replacement breaks the test")
     def test_graal_python_args(self):

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/runtime/EmulatedPosixSupport.java

@@ -2304,6 +2304,8 @@ public int forkExec(Object[] executables, Object[] args, Object cwd, Object[] en
                     throw createUnsupportedFeature("Only key=value environment variables are supported in fork_exec");
                 }
             }
+        } else {
+            envMap = new HashMap<>(environ);
         }
 
         String[] argStrings;