interpreter: flatten environment() initial values

Turns out listify() flattens by default, but stringlistify() cannot
flatten... How do I realize this only now?

Fixes: #8727

2 files changed, 5 insertions, 1 deletions

diff --git a/test cases/common/41 test args/meson.build b/test cases/common/41 test args/meson.build
index 81d3491..b21f1ad 100644
--- a/test cases/common/41 test args/meson.build
+++ b/test cases/common/41 test args/meson.build
@@ -23,7 +23,7 @@ test('environment variables 2', e3, env : env2)
 env_array = ['MESONTESTING=picklerror']
 testfile = files('testfile.txt')
 testerpy = find_program('tester.py')
-test('file arg', testerpy, args : testfile, env : env_array)
+test('file arg', testerpy, args : testfile, env : [env_array, 'TEST_LIST_FLATTENING=1'])
 
 copy = find_program('copyfile.py')
 tester = executable('tester', 'tester.c')
diff --git a/test cases/common/41 test args/tester.py b/test cases/common/41 test args/tester.py
index 0b4010a..b5884cc 100755
--- a/test cases/common/41 test args/tester.py
+++ b/test cases/common/41 test args/tester.py
@@ -1,6 +1,10 @@
 #!/usr/bin/env python3
 
 import sys
+import os
+
+assert os.environ['MESONTESTING'] == 'picklerror'
+assert os.environ['TEST_LIST_FLATTENING'] == '1'
 
 with open(sys.argv[1]) as f:
     if f.read() != 'contents\n':