Hello, While attempting to debug a crash in jami-qt, I've noticed that GDB would fail to load the symbol tables of the shared libraries it uses, for example qtdeclarative. It seems that grafts are to blame. Let's start by looking at the debug files found for the qtdeclarative libQt5Qml.so.5 shared library: --8<---------------cut here---------------start------------->8--- $ guix build qtdeclarative | xargs -I{} find -L {} -name *libQt5Qml.so.5* substitute: updating substitutes from 'http://127.0.0.1:8080'... 100.0% substitute: updating substitutes from 'https://ci.guix.gnu.org'... 100.0% The following files will be downloaded: /gnu/store/g1gxfbkyxilnx7s6mjdlj697y5n5wazn-qtdeclarative-5.15.2-debug /gnu/store/nvzvrr137qfqsn2875yrs9ilfd12wi96-qtdeclarative-5.15.2 substituting /gnu/store/g1gxfbkyxilnx7s6mjdlj697y5n5wazn-qtdeclarative-5.15.2-debug... downloading from https://ci.guix.gnu.org/nar/lzip/g1gxfbkyxilnx7s6mjdlj697y5n5wazn-qtdeclarative-5.15.2-debug ... qtdeclarative-5.15.2-debug 94.9MiB 1.2MiB/s 01:21 [##################] 100.0% The following graft will be made: /gnu/store/djhcai9rixm2j3jlamwdhsgwgidg7w74-qtdeclarative-5.15.2.drv applying 2 grafts for /gnu/store/djhcai9rixm2j3jlamwdhsgwgidg7w74-qtdeclarative-5.15.2.drv ... grafting '/gnu/store/g1gxfbkyxilnx7s6mjdlj697y5n5wazn-qtdeclarative-5.15.2-debug' -> '/gnu/store/l3h4ka7v3j1yhik0f1phwch08a09p0bx-qtdeclarative-5.15.2-debug'... grafting '/gnu/store/nvzvrr137qfqsn2875yrs9ilfd12wi96-qtdeclarative-5.15.2' -> '/gnu/store/pryhgzb6cwnzsskqwldwc6dxr6nwnywf-qtdeclarative-5.15.2'... updating '.gnu_debuglink' CRC in '/gnu/store/pryhgzb6cwnzsskqwldwc6dxr6nwnywf-qtdeclarative-5.15.2/bin/qml' updating '.gnu_debuglink' CRC in '/gnu/store/pryhgzb6cwnzsskqwldwc6dxr6nwnywf-qtdeclarative-5.15.2/bin/q [...] updating '.gnu_debuglink' CRC in '/gnu/store/pryhgzb6cwnzsskqwldwc6dxr6nwnywf-qtdeclarative-5.15.2/lib/qt5/qml/QtQuick/Window.2/libwindowplugin.so' updating '.gnu_debuglink' CRC in '/gnu/store/pryhgzb6cwnzsskqwldwc6dxr6nwnywf-qtdeclarative-5.15.2/lib/qt5/qml/QtTest/libqmltestplugin.so' successfully built /gnu/store/djhcai9rixm2j3jlamwdhsgwgidg7w74-qtdeclarative-5.15.2.drv /gnu/store/l3h4ka7v3j1yhik0f1phwch08a09p0bx-qtdeclarative-5.15.2-debug/lib/debug/gnu/store/pryhgzb6cwnzsskqwldwc6dxr6nwnywf-qtdeclarative-5.15.2/lib/libQt5Qml.so.5.15.2.debug /gnu/store/pryhgzb6cwnzsskqwldwc6dxr6nwnywf-qtdeclarative-5.15.2/lib/libQt5Qml.so.5.15.2 /gnu/store/pryhgzb6cwnzsskqwldwc6dxr6nwnywf-qtdeclarative-5.15.2/lib/libQt5Qml.so.5 /gnu/store/pryhgzb6cwnzsskqwldwc6dxr6nwnywf-qtdeclarative-5.15.2/lib/libQt5Qml.so.5.15 --8<---------------cut here---------------end--------------->8--- So far so good. The file hierarchy under the debug output matches the actual shared library file name. Next, let's verify which qtdeclarative shared libraries jami-qt is dynamically linked against: --8<---------------cut here---------------start------------->8--- $ guix build jami-qt | tail -1 | xargs -I{} ldd {}/bin/.jami-qt-real | grep qtdeclarative libQt5QuickWidgets.so.5 => /gnu/store/mjl02yma4r5xjark6d8pp5h2j0a2vccs-qtdeclarative-5.15.2/lib/libQt5QuickWidgets.so.5 (0x00007fb9e38a8000) libQt5Quick.so.5 => /gnu/store/mjl02yma4r5xjark6d8pp5h2j0a2vccs-qtdeclarative-5.15.2/lib/libQt5Quick.so.5 (0x00007fb9dba47000) libQt5QmlModels.so.5 => /gnu/store/mjl02yma4r5xjark6d8pp5h2j0a2vccs-qtdeclarative-5.15.2/lib/libQt5QmlModels.so.5 (0x00007fb9db9c3000) libQt5Qml.so.5 => /gnu/store/mjl02yma4r5xjark6d8pp5h2j0a2vccs-qtdeclarative-5.15.2/lib/libQt5Qml.so.5 (0x00007fb9dae4e000) --8<---------------cut here---------------end--------------->8--- Oops! The actual store file name of the libQt5Qml.so.5 known to jami-qt is *not* the same as the one obtained earlier, which explains why GDB doesn't find its symbols. Without grafts, the first command gives: --8<---------------cut here---------------start------------->8--- $ guix build --no-grafts qtdeclarative | xargs -I{} find -L {} -name *libQt5Qml.so.5* /gnu/store/g1gxfbkyxilnx7s6mjdlj697y5n5wazn-qtdeclarative-5.15.2-debug/lib/debug/gnu/store/nvzvrr137qfqsn2875yrs9ilfd12wi96-qtdeclarative-5.15.2/lib/libQt5Qml.so.5.15.2.debug /gnu/store/nvzvrr137qfqsn2875yrs9ilfd12wi96-qtdeclarative-5.15.2/lib/libQt5Qml.so.5 /gnu/store/nvzvrr137qfqsn2875yrs9ilfd12wi96-qtdeclarative-5.15.2/lib/libQt5Qml.so.5.15 /gnu/store/nvzvrr137qfqsn2875yrs9ilfd12wi96-qtdeclarative-5.15.2/lib/libQt5Qml.so.5.15.2 --8<---------------cut here---------------end--------------->8--- Which still doesn't match the libraries jami-qt is linked with. I'm out of ideas for now. Would someone have a clue? Thank you! Maxim