diff --git a/scripts/qapi/common.py b/scripts/qapi/common.py
index a58e90497849..2b461648545d 100644
--- a/scripts/qapi/common.py
+++ b/scripts/qapi/common.py
@@ -742,8 +742,9 @@ def check_if_str(ifcond, info):
         if not isinstance(ifcond, str):
             raise QAPISemError(
                 info, "'if' condition must be a string or a list of strings")
-        if ifcond == '':
-            raise QAPISemError(info, "'if' condition '' makes no sense")
+        if ifcond.strip() == '':
+            raise QAPISemError(info, "'if' condition '%s' makes no sense"
+                               % ifcond)
 
     ifcond = expr.get('if')
     if ifcond is None:
diff --git a/tests/qapi-schema/bad-if-list.err b/tests/qapi-schema/bad-if-list.err
index 0af6316f783b..53af0990834b 100644
--- a/tests/qapi-schema/bad-if-list.err
+++ b/tests/qapi-schema/bad-if-list.err
@@ -1 +1 @@
-tests/qapi-schema/bad-if-list.json:2: 'if' condition '' makes no sense
+tests/qapi-schema/bad-if-list.json:2: 'if' condition ' ' makes no sense
diff --git a/tests/qapi-schema/bad-if-list.json b/tests/qapi-schema/bad-if-list.json
index 49ced9b9cac4..ea3d95bb6b5f 100644
--- a/tests/qapi-schema/bad-if-list.json
+++ b/tests/qapi-schema/bad-if-list.json
@@ -1,3 +1,3 @@
 # check invalid 'if' content
 { 'struct': 'TestIfStruct', 'data': { 'foo': 'int' },
-  'if': ['foo', ''] }
+  'if': ['foo', ' '] }