ag 2 <(echo 2) gets assertion "p >= path" failed: .. /cygwin-3.1.7 ... /cygwin/path.cc", line 3065, function: int symlink_info::check

[Ken Brown]

On 9/6/2020 3:47 PM, Ken Brown via Cygwin wrote:
> On 9/6/2020 2:43 PM, David Dyck via Cygwin wrote:
>> This command triggers an assertion failure
>>    "ag" is from the_silver_searcher
>>
>> $ ag 2 <(echo 2)
>> assertion "p >= path" failed: file
>> "/home/corinna/src/cygwin/cygwin-3.1.7/cygwin-3.1.7-1.x86_64/src/newlib-cygwin/winsup/cygwin/path.cc", 
>>
>> line 3065, function: int symlink_info::check(char*, const
>> suffix_info*, fs_info&, path_conv_handle&)
>> Aborted (core dumped)
>>
>>   3473k 2020/08/22 C:\cygwin64\bin\cygwin1.dll
>>      Cygwin DLL version info:
>>          DLL version: 3.1.7
>> bash                                    4.4.12-3                        OK
>> the_silver_searcher                     2.2.0-1                         OK
> [...]
>> assertion "p >= path" failed: file
>> "/home/corinna/src/cygwin/cygwin-3.1.7/cygwin-3.1.7-1.x86_64/src/newlib-cygwin/winsup/cygwin/path.cc", 
>>
>> line 3065, function: int symlink_info::check(char*, const
>> suffix_info*, fs_info&, path_conv_handle&)
>> Aborted (core dumped)
> [...]
>> I've reported this on github as an "ag" bug, but I think it is a bug in cygwin
> 
> An assertion failure in Cygwin code is a Cygwin bug.  I'll take a look.

Running

   bash -c '/usr/bin/ag 2 <(echo 2)'

under strace yields the following:

   242  191767 [main] ag 33659 open: open(/dev/fd/63/.ignore, 0x0)
[...]
    30  192584 [main] ag 33659 mount_info::conv_to_win32_path: src_path 
/proc/self/fd/63/.ignore, dst /proc/self/fd/63/.ignore, flags 0x0, rc 0
[...]
    31  193366 [main] ag 33659 mount_info::conv_to_win32_path: 
conv_to_win32_path (pipe:[4295036184]/.ignore)
[...]
    31  193550 [main] ag 33659 mount_info::conv_to_win32_path: 
conv_to_win32_path (pipe:[4295036184])
[...]
    34  193615 [main] ag 33659 symlink_info::check: 0xC0000034 = NtCreateFile 
(\??\C:pipe:[4295036184])

The assertion fails because the path 'C:pipe:[4295036184]' doesn't contain a 
backslash.  But probably we should never have allowed ourselves to get to the 
point of considering that path.

I don't have any more time to think about this today, but I'll get back to it 
tomorrow if no one beats me to it.

Ken