Force stdout to always encode UTF8

filecheck/FileCheck.py

@@ -200,6 +200,10 @@ def implicit_check_line(check_not_check, strict_mode, line):
 
 
 def main():
+    # Force UTF-8 to be sent to stdout.
+    # https://stackoverflow.com/a/3597849/598057
+    sys.stdout = open(1, 'w', encoding='utf-8', closefd=False)
+
     args = None
     input_lines = None
 

tests/integration/tests/general/02-utf8-characters-printed-at-failure/sample.check

@@ -0,0 +1 @@
+CHECK: Match line that does not exist in input.

tests/integration/tests/general/02-utf8-characters-printed-at-failure/sample.input

@@ -0,0 +1,2 @@
+# © A line with UTF-8 produces
+# vadsэавфыаЭХÜÜÄ

tests/integration/tests/general/02-utf8-characters-printed-at-failure/sample.itest

@@ -0,0 +1,11 @@
+RUN: %cat "%S/sample.input" | \
+RUN:    %expect_exit 1 %FILECHECK_EXEC "%S/sample.check" --dump-input=fail | \
+RUN:      %FILECHECK_TESTER_EXEC "%s" \
+RUN:        --strict-whitespace \
+RUN:        --match-full-lines
+
+CHECK:{{.*}}/sample.check:1:8: error: CHECK: expected string not found in input
+CHECK:{{.*}}CHECK: Match line that does not exist in input.
+CHECK:{{.*}}<stdin>:1:1: note: scanning from here
+CHECK:{{.*}}# © A line with UTF-8 produces
+CHECK:{{.*}}# vadsэавфыаЭХÜÜÄ

tests/integration/tools/expect_exit.py

@@ -1,6 +1,10 @@
 import subprocess
 import sys
 
+# Force UTF-8 to be sent to stdout.
+# https://stackoverflow.com/a/3597849/598057
+sys.stdout = open(1, 'w', encoding='utf-8', closefd=False)
+
 if len(sys.argv) <= 2:
     print("error: expect_exit: expect arguments to be provided")
     exit(1)