Warn if PB_MAX_REQUIRED_FIELDS is not large enough.

1 files changed, 10 insertions, 0 deletions

diff --git a/generator/nanopb_generator.py b/generator/nanopb_generator.py
index 1e7e1f98..730c0aab 100644
--- a/generator/nanopb_generator.py
+++ b/generator/nanopb_generator.py
@@ -402,6 +402,16 @@ def generate_header(dependencies, headername, enums, messages):
     for msg in messages:
         yield msg.fields_declaration() + '\n'
     
+    count_required_fields = lambda m: len([f for f in msg.fields if f.htype == 'PB_HTYPE_REQUIRED'])
+    largest_msg = max(messages, key = count_required_fields)
+    largest_count = count_required_fields(largest_msg)
+    if largest_count > 64:
+        yield '\n/* Check that missing required fields will be properly detected */\n'
+        yield '#if PB_MAX_REQUIRED_FIELDS < %d\n' % largest_count
+        yield '#warning Properly detecting missing required fields in %s requires \\\n' % largest_msg.name
+        yield '         setting PB_MAX_REQUIRED_FIELDS to %d or more.\n' % largest_count
+        yield '#endif\n'
+    
     yield '\n#endif\n'
 
 def generate_source(headername, enums, messages):