[PATCH] remote: Return NULL extra_info/name if they are empty

[Simon Marchi]

On 2017-12-11 19:24, Pedro Alves wrote:
> On 12/11/2017 06:21 PM, Simon Marchi wrote:
>> Commit
>> 
>>   remote: C++ify thread_item and threads_listing_context
>>   21fe1c752e254167d953fa8c846280f63a3a5290
>> 
>> broke the test gdb.threads/names.exp.  The problem is that since we 
>> now
>> use an std::string to hold the extra_info, an empty string is returned
>> by target_extra_thread_info to print_thread_info_1 when the remote 
>> stub
>> didn't send any extra info, instead of NULL before.  Because of that,
>> print_thread_info_1 prints the extra info between parentheses, which
>> results in some spurious empty parentheses.
>> 
>>   Expected: * 1    Thread 22752.22752 "main" all_threads_ready () at 
>> ...
>>   Actual  : * 1    Thread 22752.22752 "main" () all_threads_ready () a 
>> ...
>> 
>> Since the bug was introduced by a behavior change in the remote 
>> target,
>> I chose to fix it on the remote target side by making it return NULL
>> when the extra string is empty.  This will avoid possibly changing the
>> behavior of the common code and affecting other targets.
>> 
>> The name field has the same problem.  If a remote stub returns no 
>> thread
>> names, remote_thread_name will return an empty string instead of NULL,
>> so print_thread_info_1 will show empty quotes ("") instead of nothing.
>> 
>> gdb/ChangeLog:
>> 
>> 	PR gdb/22556
>> 	* remote.c (remote_thread_name): Return NULL if name is empty.
>> 	(remote_threads_extra_info): Return NULL if extra info is empty.
> 
> Looks good, thanks.
> 
> Pedro Alves

Thanks, pushed.

Simon