tensorflow: Build tensorflow 2.2.0 failed in '@upb//:upb' with the length argument in strncpy

System information

• OS Platform and Distribution (e.g., Linux Ubuntu 16.04): Linux Ubuntu 18.04.4 LTS
• TensorFlow installed from (source or binary): source
• TensorFlow version: 2.2.0
• Python version: 3.7.7
• Bazel version (if compiling from source): 2.0.0
• GCC/Compiler version (if compiling from source): 10.1.0

Describe the problem

In file included from /usr/include/string.h:494,                                                                
                 from external/upb/upb/upb.h:16,                                                                                                                                                                                              
                 from external/upb/upb/upb.c:2:                                                                 
In function 'strncpy',                                                                                         
    inlined from 'upb_status_seterrmsg' at external/upb/upb/upb.c:40:3:                                         
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:106:10: error: '__builtin_strncpy' specified bound 127 equals destination size [-Werror=stringop-truncation]                                                             
  106 |   return __builtin___strncpy_chk (__dest, __src, __len, __bos (__dest));                                                                                                                                                              
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                                 
cc1: all warnings being treated as errors                                                                      
Target //tensorflow/tools/pip_package:build_pip_package failed to build                                         

Provide the exact sequence of commands / steps that you executed before running into the problem

Build with bazel following the documentation.

Any other info / logs

It’s a trivial misuse of strncpy. Here is a simple fix.

--- upb/upb/upb.c~      2020-05-12 14:33:15.046048687 -0500                                                                                                                                           
+++ upb/upb/upb.c       2020-05-12 14:33:30.281987830 -0500                                                                                                                                           
@@ -37,7 +37,7 @@                                                                                                                                                                                                                                             
 void upb_status_seterrmsg(upb_status *status, const char *msg) {                                                                                                                                                                                             
   if (!status) return;                                                                                                                                                                                                                                       
   status->ok = false;                                         
-  strncpy(status->msg, msg, sizeof(status->msg));             
+  strncpy(status->msg, msg, sizeof(status->msg)-1);           
   nullz(status);                                              
 }