How to solve: Could not find the Qt platform plugin "headless"

[jsky]

I am compiling Calibre on Ubuntu using the command

python3.14 setup.py bootstrap

, but I get an error that the Qt platform cannot find the headless plugin.

Compiling content-server translations
qt.qpa.plugin: Could not find the Qt platform plugin "headless" in "/root/calibre/src/calibre/plugins"

However, libheadless.so does exist in /root/calibre/src/calibre/plugins,

root@ubuntu-linux-2404:~/calibre/src/calibre/plugins# ls
bzzdec.so              html_as_json.so             libmtp.so           piper.so               sqlite_extension.so
certgen.so             html_syntax_highlighter.so  libusb.so           platforms              tokenizer.so
cPalmdoc.so            hunspell.so                 lzx.so              podofo.so              translator.so
fast_css_transform.so  hyphen.so                   matcher.so          progress_indicator.so  uchardet.so
fast_html_entities.so  icu.so                      msdes.so            rcc_backend.so         unicode_names.so
ffmpeg.so              imageops.so                 _patiencediff_c.so  speedup.so
freetype.so            libheadless.so              pictureflow.so      sqlite_custom.so

and I am not sure how to fix this.

the detail infos:

root@ubuntu-linux-2404:~/calibre# python3.14 setup.py bootstrap

*
* Running build
*

Package libonnxruntime was not found in the pkg-config search path.
Perhaps you should add the directory containing `libonnxruntime.pc'
to the PKG_CONFIG_PATH environment variable
Package 'libonnxruntime', required by 'virtual:world', not found
Package libonnxruntime was not found in the pkg-config search path.
Perhaps you should add the directory containing `libonnxruntime.pc'
to the PKG_CONFIG_PATH environment variable
Package 'libonnxruntime', required by 'virtual:world', not found
Package libonnxruntime was not found in the pkg-config search path.
Perhaps you should add the directory containing `libonnxruntime.pc'
to the PKG_CONFIG_PATH environment variable
Package 'libonnxruntime', required by 'virtual:world', not found
Building 31 extensions
Compiling 3 files...
g++ -Wall -DNDEBUG -fno-strict-aliasing -pipe -O3 -fPIC -fvisibility=hidden -pthread -fdiagnostics-color=always -I/usr/local/include/python3.14 '-DCALIBRE_MODINIT_FUNC=extern "C" __attribute__ ((visibility ("default"))) PyObject*' -std=c++20 -I/root/calibre/src/calibre/utils/translator -c /root/calibre/src/calibre/utils/translator/plural_expression_parser.cpp -o /root/calibre/build/objects/translator/plural_expression_parser.o

g++ -Wall -DNDEBUG -fno-strict-aliasing -pipe -O3 -fPIC -fvisibility=hidden -pthread -fdiagnostics-color=always -I/usr/local/include/python3.14 '-DCALIBRE_MODINIT_FUNC=extern "C" __attribute__ ((visibility ("default"))) PyObject*' -std=c++20 -I/root/calibre/src/calibre/utils/translator -c /root/calibre/src/calibre/utils/translator/mo_parser.cpp -o /root/calibre/build/objects/translator/mo_parser.o

g++ -Wall -DNDEBUG -fno-strict-aliasing -pipe -O3 -fPIC -fvisibility=hidden -pthread -fdiagnostics-color=always -I/usr/local/include/python3.14 '-DCALIBRE_MODINIT_FUNC=extern "C" __attribute__ ((visibility ("default"))) PyObject*' -std=c++20 -I/root/calibre/src/calibre/utils/translator -c /root/calibre/src/calibre/utils/translator/main.cpp -o /root/calibre/build/objects/translator/main.o

Linking 1 files...
g++ /root/calibre/build/objects/translator/main.o /root/calibre/build/objects/translator/mo_parser.o /root/calibre/build/objects/translator/plural_expression_parser.o -o /root/calibre/src/calibre/plugins/translator.so -Wall -shared -L/usr/local/lib -lpython3.14 -Xlinker -export-dynamic


####### Building headless QPA plugin #######
* build took 1.1 seconds

*
* Running iso_data
*

* iso_data took 0.0 seconds

*
* Running iso639
*

Packing ISO-639 codes to /root/calibre/resources/localization/iso639.calibre_msgpack
* iso639 took 0.7 seconds

*
* Running iso_data
*

* iso_data took 0.0 seconds

*
* Running iso3166
*

Packing ISO-3166 codes to /root/calibre/resources/localization/iso3166.calibre_msgpack
* iso3166 took 0.0 seconds

*
* Running translations
*

Compiling main UI translation files...
	Compiling 0 files
Compiling ISO639 files...

____________________ WARNING ____________________
No ISO 639 translations for locale: nb
__________________________________________________
	Compiling 0 files
Compiling ISO3166 files...

____________________ WARNING ____________________
No ISO 3166 translations for locale: nb
__________________________________________________
	Compiling 0 files
Compiling content-server translations
qt.qpa.plugin: Could not find the Qt platform plugin "headless" in "/root/calibre/src/calibre/plugins"
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.

Available platform plugins are: linuxfb, vnc, minimalegl, eglfs, offscreen, minimal, vkkhrdisplay, wayland-brcm, wayland-egl, wayland, xcb.

已中止 (核心已转储)

[kovidgoyal]

run with QT_DEBUG_PLUGINS=1