diff --git a/contrib/python3-whitelist b/contrib/python3-whitelist
--- a/contrib/python3-whitelist
+++ b/contrib/python3-whitelist
@@ -258,6 +258,7 @@
 test-merge8.t
 test-merge9.t
 test-minifileset.py
+test-minirst.py
 test-mq-git.t
 test-mq-header-date.t
 test-mq-header-from.t
diff --git a/mercurial/minirst.py b/mercurial/minirst.py
--- a/mercurial/minirst.py
+++ b/mercurial/minirst.py
@@ -169,7 +169,7 @@
         if not itemre.match(line1):
             return False
         if singleline:
-            return line2 == '' or line2[0] == ' ' or itemre.match(line2)
+            return line2 == '' or line2[0:1] == ' ' or itemre.match(line2)
         else:
             return line2.startswith(' ')