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Date: Sun, 6 Sep 2020 15:15:13 -0700
Message-ID: <CAJtSMgsu3u+DpqBmot8=o3z8zxBjU-yAY9fm8-ztz1xpMkFCEQ@mail.gmail.com>
Subject: Re: ag 2 <(echo 2) gets assertion "p >= path" failed: ..
 /cygwin-3.1.7 ... /cygwin/path.cc", line 3065,
 function: int symlink_info::check
To: moss@cs.umass.edu
From: David Dyck via Cygwin <cygwin@cygwin.com>
Reply-To: David Dyck <david.dyck@gmail.com>
Cc: cygwin@cygwin.com
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On Sun, Sep 6, 2020 at 12:07 PM Eliot Moss <moss@cs.umass.edu> 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&)

>
> I just tried this:
>
>    grep 2 <(echo 2)
>
> on cygwin 3.1.7 and it worked fine.  I am not familiar with Silver
Searcher, but it would
> seem that the problem is more idiosyncratic to that program than to
Cygwin more generally.
> I am _not_ saying the problem is not in Cygwin - only that ag must be
doing something
> somewhat different from what grep does with <( ) command input.  Perhaps
ag is testing
> what sort of "thing" (device, etc.) the input file is, while grep does
not - something
> like that might give different behavior.
>
> Now I have CYGWIN=winsymlinks:native, which may (almost certainly does)
affect what
> path.cc is doing (the error message is concerned about symlinks;
presumably Cygwin
> is trying to check whether /dev/fd/63 is a symlink.
>
> Well, those are the clues I can offer :-) ...   EM

Thanks,  I tried
  export CYGWIN=winsymlinks:native
and it still asserted

I think the "ag" uses mmap and pthreads - at least that is what the manual
page indicated -
 though even when I passed --nommap I still got the assertion,

From man ag:

> How is it so fast?
> * Searching for literals (no regex) uses Boyer-Moore-Horspool strstr.
> * Files are mmap()ed instead of read into a buffer.
> * If you're building with PCRE 8.21 or greater, regex searches use the JIT
> compiler.
> * Ag calls pcre_study() before executing the regex on a jillion files.
> * Instead of calling fnmatch() on every pattern in your ignore files,
> non-regex patterns are loaded into an array and binary searched.
> * Ag uses Pthreads to take advantage of multiple CPU cores and search
> files in parallel.
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