Re: Bug in apgcc when encountering dependencies on non-lib libraries

On 10MAR2009 Jan Niklas Hasse wrote:
> Thanks for the description and the patch! I committed it in r2550.
> http://trac.autopackage.org/changeset/2550

Cool, thanks!

> While testing your patch I recognized that apgcc only prints a confusing 
> error message when libuuid.so doesn't exist:
> 
> $ sudo mv /usr/lib/libuuid.so backup.so
> $ env APBUILD_STATIC=uuid apgcc -o whatever whatever.c
> objdump: '': No such file
> $ sudo mv backup.so /usr/lib/libuuid.so
> $ env APBUILD_STATIC=uuid apgcc -o whatever whatever.c
> $
> 
> Isn't this a bug we should fix, too? Before your patch, there didn't 
> seem to be an error message at all. I don't know what causes this as I'm 
> not that familiar with apbuild.

I hadn't seen that error before.  Note that nonexistent libraries
don't produce an error message:

     $ env APBUILD_STATIC=bogus apgcc -o whatever whatever.c
     $

I just stepped through the code, and it looks like the "objdump: '':
No such file" error is output when the .a file exists but the .so file
doesn't.  I've attached a patch that outputs a more user-friendly
warning message in that case.  The warning is written to standard
output for consistency with the APBUILD_NO_STATIC_X warning right
above it in the code, but, personally, I'd prefer using Perl's warn
statement to write warning messages to standard error.

As a bonus patch, I fixed a bug in GCC.pm that I encountered along the
way.  GCC.pm's getSearchPaths subroutine was incorrectly constructing
the library search path.  Instead of appending the new path list onto
the old list, it was appending only a _reference_ to the new list.

-- Scott

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--- share/apbuild/Apbuild/GCC.pm.2550	2009-03-10 11:40:18.743120000 -0600
+++ share/apbuild/Apbuild/GCC.pm	2009-03-10 11:37:49.113971000 -0600
@@ -338,7 +338,7 @@
 	};
 	$self->foreach($args, $callback);
 
-	push @{$paths}, $self->{searchPaths};
+	push @{$paths}, @{$self->{searchPaths}};
 }
 
 
--- bin/apgcc.2550	2009-03-10 11:40:01.693108000 -0600
+++ bin/apgcc	2009-03-10 11:42:17.988242000 -0600
@@ -798,7 +798,12 @@
 				# find the DT_NEEDED entries that this library-to-be-made-static
 				# has so that final linking works (the deps need to be added after the static lib so the bogus stripper doesn't remove them)
 				my ($r, $w);
-				my $pid = open2 ($r, $w, 'objdump', '-p', searchLib("lib$lib.so", \@searchPaths));
+				my $abslib = searchLib("lib$lib.so", \@searchPaths);
+				if (!defined $abslib) {
+				        print "WARNING: Failed to find lib$lib.so in ", join(":", @searchPaths), ".\n";
+				        next;
+				}
+				my $pid = open2 ($r, $w, 'objdump', '-p', $abslib);
 				close ($w);
 				foreach (<$r>) {
 					next unless (/^  NEEDED\s+lib(.+?)\.so/);