On 9/6/2020 6:15 PM, David Dyck wrote:
On Sun, Sep 6, 2020 at 12:07 PM Eliot Moss <m...@cs.umass.edu
<mailto:m...@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.
Yes, mmap would fail on a device file like this, but the failure is when trying
to open a
.ignore file under the device file (which won't exist), as I recall. As others
indicated,
there is a problem in cygwin. It might have to do with flavors of symlink, but
maybe not.
Anyway, seems folks are onto it.
Best wishes - EM
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