3.7 bpo-32852: Fix trace changing sys.argv to tuple GH-5692

Lib/test/test_trace.py

@@ -387,5 +387,15 @@ def test_listfuncs_flag_success(self):
             status, stdout, stderr = assert_python_ok('-m', 'trace', '-l', TESTFN)
             self.assertIn(b'functions called:', stdout)
 
+    def test_sys_argv_list(self):
+        with open(TESTFN, 'w') as fd:
+            self.addCleanup(unlink, TESTFN)
+            fd.write("import sys\n")
+            fd.write("print(type(sys.argv))\n")
+
+        status, direct_stdout, stderr = assert_python_ok(TESTFN)
+        status, trace_stdout, stderr = assert_python_ok('-m', 'trace', '-l', TESTFN)
+        self.assertIn(direct_stdout.strip(), trace_stdout)
+
 if __name__ == '__main__':
     unittest.main()

Lib/trace.py

@@ -705,7 +705,7 @@ def parse_ignore_dir(s):
     if opts.filename is None:
         parser.error('filename is missing: required with the main options')
 
-    sys.argv = opts.filename, *opts.arguments
+    sys.argv = [opts.filename, *opts.arguments]
     sys.path[0] = os.path.dirname(opts.filename)
 
     t = Trace(opts.count, opts.trace, countfuncs=opts.listfuncs,

Misc/NEWS.d/next/Library/2018-02-15-12-04-29.bpo-32852.HDqIxM.rst

@@ -0,0 +1 @@
+Make sure sys.argv remains as a list when running trace.