Re: strange bug with python24+darwin_8, py-wxpython and xml parsing
Date: Mon, 06 Aug 2007 22:36:25 +0200 From: Mark Asbach <asbach@ient.rwth-aachen.de> when using py-xml together with py-wxpython, I get a reproductible bus error whenever I try to use sax or minidom (both relying on expat). Invoking the parsers crashes the application with a bus error. The workaround I found is to import xml.parsers.pyexpat before importing wx - but this is a workaround, not a bug fix.
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Can someone comment on this? What could I do to narrow the bug?
Hi Mark, * This problem may be caused by wxPython being built/linking against older versions of libexpat than pyexpat is. * A solution may be to do a clean build and install of both wxPython and pyexpat. (libxml has been recently upgraded in version from 2.6.28_0->2.6.28_1, perhaps causing your incompatible builds?) * This bug is documented here: http://sourceforge.net/tracker/index.php? func=detail&aid=1295808&group_id=5470&atid=105470 http://sourceforge.net/tracker/index.php? func=detail&aid=1075984&group_id=5470&atid=105470 * It notes that the problem is caused by version mismatches. A solution that avoids the problem has been applied in 2.5, but not in 2,4 * Here are a couple of other references to the problem (without solutions) http://mail.python.org/pipermail/xml-sig/2005-March/011026.html http://archives.devshed.com/forums/development-94/sax-make-parser- segfaults-1610644.html des.
Derek Harland <derek <at> chocolate-fish.com> writes:
Date: Mon, 06 Aug 2007 22:36:25 +0200 From: Mark Asbach <asbach <at> ient.rwth-aachen.de> when using py-xml together with py-wxpython, I get a reproductible bus error whenever I try to use sax or minidom (both relying on expat). Invoking the parsers crashes the application with a bus error. The workaround I found is to import xml.parsers.pyexpat before importing wx - but this is a workaround, not a bug fix.
<backtrace clipped>
Can someone comment on this? What could I do to narrow the bug?
Hi Mark,
* This problem may be caused by wxPython being built/linking against older versions of libexpat than pyexpat is.
Hi Apparently the wxwidgets Portfile is causing this error. "configure.ldflags" lacks "-L${prefix}/lib" and thus configure thinks that expat does not exist in the system and links to its own version of the library. Cheers Lorenz
Lorenz Schori <lorenz.schori@gmx.ch> writes:
Date: Mon, 06 Aug 2007 22:36:25 +0200 From: Mark Asbach <asbach <at> ient.rwth-aachen.de> when using py-xml together with py-wxpython, I get a reproductible bus error whenever I try to use sax or minidom (both relying on expat). Invoking the parsers crashes the application with a bus error. The workaround I found is to import xml.parsers.pyexpat before importing wx - but this is a workaround, not a bug fix.
<backtrace clipped>
Can someone comment on this? What could I do to narrow the bug?
Hi Mark,
* This problem may be caused by wxPython being built/linking against older versions of libexpat than pyexpat is.
Hi
Apparently the wxwidgets Portfile is causing this error. "configure.ldflags" lacks "-L${prefix}/lib" and thus configure thinks that expat does not exist in the system and links to its own version of the library.
I think the Portfile's configure.ldflags should be configure.ldflags-append. -L${prefix}/lib is is a default now, but if you don't use -append it gets overwritten. Mark
On Aug 9, 2007, at 11:28, Lorenz Schori wrote:
Derek Harland <derek <at> chocolate-fish.com> writes:
Date: Mon, 06 Aug 2007 22:36:25 +0200 From: Mark Asbach <asbach <at> ient.rwth-aachen.de> when using py-xml together with py-wxpython, I get a reproductible bus error whenever I try to use sax or minidom (both relying on expat). Invoking the parsers crashes the application with a bus error. The workaround I found is to import xml.parsers.pyexpat before importing wx - but this is a workaround, not a bug fix.
<backtrace clipped>
Can someone comment on this? What could I do to narrow the bug?
* This problem may be caused by wxPython being built/linking against older versions of libexpat than pyexpat is.
Apparently the wxwidgets Portfile is causing this error. "configure.ldflags" lacks "-L${prefix}/lib" and thus configure thinks that expat does not exist in the system and links to its own version of the library.
I agree. When I configure wxwidgets, I see: configure: WARNING: system expat library not found, will use built-in instead "-L${prefix}/lib" should be in the LDFLAGS by default for all portfiles. MacPorts base is supposed to ensure that. But wxwidgets's use of configure.ldflags is overriding the MacPorts defaults. This seems to have been done deliberately in r25114 for ticket #11577 to fix a different problem -- perhaps the problem that "-L${prefix}/ lib" caused the wxwidgets build to pick up libraries from the previous wxwidgets installation? One could use configure.ldflags-append instead of configure.ldflags, but that would still put "-L${prefix}/lib" first, which might still cause the same problems as in #11577. Hopefully putting "-L${prefix}/lib" at the end would be sufficient: Index: Portfile =================================================================== --- Portfile (revision 27571) +++ Portfile (working copy) @@ -53 +53 @@ -configure.ldflags -L${build.dir}/lib +configure.ldflags -L${build.dir}/lib -L${prefix}/lib
participants (4)
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Derek Harland
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Lorenz Schori
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markd＠macports.org
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Ryan Schmidt