[OE-core] [PATCH] archiver: avoid empty incfile in ar_recipe

[Andrei Gherzan]

Hi Grygorii,

On 04/11/2019 15:09, Grygorii Tertychnyi (gtertych) wrote:
> Andrei,
> 
> From: Andrei Gherzan <andrei at gherzan.ro>
> Sent: Friday, November 1, 2019 13:28
> To: Grygorii Tertychnyi (gtertych); openembedded-core at lists.openembedded.org
> Cc: xe-linux-external(mailer list)
> Subject: Re: [OE-core] [PATCH] archiver: avoid empty incfile in ar_recipe
> 
>>> do_ar_recipe fails on perf recipe on line:
>>>
>>> include ${@bb.utils.contains('PACKAGECONFIG', 'scripting', 'perf-perl.inc', '', d)}
>>>
>>> 1. "${...}" part expands into empty string
>>> 2. bb.utils.which() takes empty string and returns first directory name from bbpath
> 
>> This doesn't sound sane. If the include directive has no argument,
>> incfile should end up None. That's what the code "assumes" at this
> 
> I agree.
> 
>> point. I would fix it either at the regex expression level or
>> stripping the matched string. I reckon the former makes more sense
>> (.*).
> 
> Not sure I understand. Archiver class does not interpret "include" directive.
> It just parses text files. The regular expression looks correct:
> 
> These lines:
> 
> 440         elif include_re.match(line):
> 441             incfile = include_re.match(line).group(1)
> 
> put "${...}" _string_ into "incfile" variable. So, "incfile" is not None at "this stage.

"${...}" it's already expanded to a white-space. So in that case it 
matches "include  ".

> Then,
> 
> 443             incfile = d.expand(incfile)
> 
> Now "incfile" is empty and nobody checks it.

incfile is not empty. It's actually a string containing one white-space.

> 
> 444             incfile = bb.utils.which(bbpath, incfile)
> 
> Now "incfile" is set to first directory name in BBPATH (wrong behavour?)
> 
> 445             if incfile:
> 446                 shutil.copy(incfile, outdir)
> 
> Exception here: "incfile" is directory, not a file.
> 

The include regex is the following:

include_re = re.compile( r"include\s+(.+)" )

The issue is that when this is matched on a string suffixed with only 
spaces, it will match the last space as group(1). This is because ".+" 
forces to match the last white-space. Changing that to ".*" will make 
the group(1) be an empty string and later the if will evaluate False.

-- 
Andrei Gherzan