Bug#1143306: fonts-montserrat: FTBFS: dh_auto_build: error: make -j2 INSTALL="install --strip-program=true" build returned exit code 2

Package: src:fonts-montserrat
Version: 9.000-5
Severity: serious
Tags: ftbfs forky sid

Dear maintainer:

During a rebuild of all packages in unstable, this package failed to build.

Below you will find the last part of the build log (probably the most
relevant part, but not necessarily). If required, the full build log
is available here:

https://people.debian.org/~sanvila/build-logs/202608/

About the archive rebuild: The build was made on virtual machines from AWS,
using sbuild and a reduced chroot with only build-essential packages.

If you cannot reproduce the bug please contact me privately, as I
am willing to provide ssh access to a virtual machine where the bug is
fully reproducible.

If this is really a bug in one of the build-depends, please use
reassign and add an affects on src:fonts-montserrat, so that this is still
visible in the BTS web page for this package.

Thanks.

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[...]
 debian/rules clean
dh clean
   dh_auto_clean
	make -j2 clean
make[1]: Entering directory '/<<PKGBUILDDIR>>'
rm -rf venv
find . -name "*.pyc" -delete
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
   dh_clean
 debian/rules binary
dh binary
   dh_update_autotools_config
   dh_autoreconf
   dh_auto_configure
   debian/rules override_dh_auto_build
make[1]: Entering directory '/<<PKGBUILDDIR>>'
dh_auto_build -- build
	make -j2 INSTALL="install --strip-program=true" build
make[2]: Entering directory '/<<PKGBUILDDIR>>'
mkdir -p venv/bin
test -d venv || python3 -m venv venv
touch venv/bin/activate; chmod +x venv/bin/activate
touch venv/touchfile
mv fonts fonts-underline fonts-alternates venv/
(for config in sources/config*.yaml; do . venv/bin/activate; gftools builder $config; done) && touch build.stamp
INFO:glyphsLib.parser:Parsing .glyphs file
INFO:glyphsLib.parser:Parsing .glyphs file
INFO:glyphsLib.parser:Parsing .glyphs file
INFO:glyphsLib.parser:Parsing .glyphs file
ninja: Jobserver mode detected:  -j2 --jobserver-auth=fifo:/tmp/GMfifo56 -- INSTALL=install\ --strip-program=true
[1/133] instantiateUfo
FAILED: [code=1] instance_ufos/MontserratUnderline-ExtraLight.ufo.json 
/usr/bin/python3 -m gftools.builder.jobrunner fontmake -i "Montserrat Underline ExtraLight" -o ufo -g MontserratUnderline.glyphs --ufo-structure=json --instance-dir instance_ufos 

Command failed:
fontmake -i Montserrat Underline ExtraLight -o ufo -g MontserratUnderline.glyphs --ufo-structure=json --instance-dir instance_ufos

INFO:fontmake.font_project:Building master UFOs and designspace from Glyphs source
INFO:glyphsLib.parser:Parsing .glyphs file
INFO:glyphsLib.builder:Running 'align_alternate_layers' transformation
INFO:glyphsLib.builder:Running 'propagate_all_anchors' transformation
INFO:fontmake.font_project:Loading 3 DesignSpace source UFOs
INFO:fontmake.font_project:Interpolating master UFOs from designspace
INFO:fontmake.font_project:Generating instance UFO for 'Montserrat Underline ExtraLight'
INFO:fontmake.font_project:Saving instance_ufos/MontserratUnderline-ExtraLight.ufo.json
fontmake: Error: In 'MontserratUnderline.glyphs' -> 'master_ufo/MontserratUnderline.designspace' -> 'instance_ufos/MontserratUnderline-ExtraLight.ufo.json': Writing UFO source failed: Extras not installed: ufoLib2[json]

[2/133] instantiateUfo
FAILED: [code=1] instance_ufos/MontserratUnderline-Thin.ufo.json 
/usr/bin/python3 -m gftools.builder.jobrunner fontmake -i "Montserrat Underline Thin" -o ufo -g MontserratUnderline.glyphs --ufo-structure=json --instance-dir instance_ufos 

Command failed:
fontmake -i Montserrat Underline Thin -o ufo -g MontserratUnderline.glyphs --ufo-structure=json --instance-dir instance_ufos

INFO:fontmake.font_project:Building master UFOs and designspace from Glyphs source
INFO:glyphsLib.parser:Parsing .glyphs file
INFO:glyphsLib.builder:Running 'align_alternate_layers' transformation
INFO:glyphsLib.builder:Running 'propagate_all_anchors' transformation
INFO:fontmake.font_project:Loading 3 DesignSpace source UFOs
INFO:fontmake.font_project:Interpolating master UFOs from designspace
INFO:fontmake.font_project:Generating instance UFO for 'Montserrat Underline Thin'
INFO:fontmake.font_project:Saving instance_ufos/MontserratUnderline-Thin.ufo.json
fontmake: Error: In 'MontserratUnderline.glyphs' -> 'master_ufo/MontserratUnderline.designspace' -> 'instance_ufos/MontserratUnderline-Thin.ufo.json': Writing UFO source failed: Extras not installed: ufoLib2[json]

ninja: build stopped: subcommand failed.
INFO:glyphsLib.parser:Parsing .glyphs file
INFO:glyphsLib.parser:Parsing .glyphs file
INFO:glyphsLib.parser:Parsing .glyphs file
INFO:glyphsLib.parser:Parsing .glyphs file
ninja: Jobserver mode detected:  -j2 --jobserver-auth=fifo:/tmp/GMfifo56 -- INSTALL=install\ --strip-program=true
[1/133] instantiateUfo
FAILED: [code=1] instance_ufos/Montserrat-Thin.ufo.json 
/usr/bin/python3 -m gftools.builder.jobrunner fontmake -i "Montserrat Thin" -o ufo -g Montserrat.glyphs --ufo-structure=json --instance-dir instance_ufos 

Command failed:
fontmake -i Montserrat Thin -o ufo -g Montserrat.glyphs --ufo-structure=json --instance-dir instance_ufos

INFO:fontmake.font_project:Building master UFOs and designspace from Glyphs source
INFO:glyphsLib.parser:Parsing .glyphs file
INFO:glyphsLib.builder:Running 'align_alternate_layers' transformation
INFO:glyphsLib.builder:Running 'propagate_all_anchors' transformation
INFO:fontmake.font_project:Loading 3 DesignSpace source UFOs
INFO:fontmake.font_project:Interpolating master UFOs from designspace
INFO:fontmake.font_project:Generating instance UFO for 'Montserrat Thin'
INFO:fontmake.font_project:Saving instance_ufos/Montserrat-Thin.ufo.json
fontmake: Error: In 'Montserrat.glyphs' -> 'master_ufo/Montserrat.designspace' -> 'instance_ufos/Montserrat-Thin.ufo.json': Writing UFO source failed: Extras not installed: ufoLib2[json]

[2/133] instantiateUfo
FAILED: [code=1] instance_ufos/Montserrat-ExtraLight.ufo.json 
/usr/bin/python3 -m gftools.builder.jobrunner fontmake -i "Montserrat ExtraLight" -o ufo -g Montserrat.glyphs --ufo-structure=json --instance-dir instance_ufos 

Command failed:
fontmake -i Montserrat ExtraLight -o ufo -g Montserrat.glyphs --ufo-structure=json --instance-dir instance_ufos

INFO:fontmake.font_project:Building master UFOs and designspace from Glyphs source
INFO:glyphsLib.parser:Parsing .glyphs file
INFO:glyphsLib.builder:Running 'align_alternate_layers' transformation
INFO:glyphsLib.builder:Running 'propagate_all_anchors' transformation
INFO:fontmake.font_project:Loading 3 DesignSpace source UFOs
INFO:fontmake.font_project:Interpolating master UFOs from designspace
INFO:fontmake.font_project:Generating instance UFO for 'Montserrat ExtraLight'
INFO:fontmake.font_project:Saving instance_ufos/Montserrat-ExtraLight.ufo.json
fontmake: Error: In 'Montserrat.glyphs' -> 'master_ufo/Montserrat.designspace' -> 'instance_ufos/Montserrat-ExtraLight.ufo.json': Writing UFO source failed: Extras not installed: ufoLib2[json]

ninja: build stopped: subcommand failed.
make[2]: *** [Makefile:23: build.stamp] Error 1
make[2]: Leaving directory '/<<PKGBUILDDIR>>'
dh_auto_build: error: make -j2 INSTALL="install --strip-program=true" build returned exit code 2
make[1]: *** [debian/rules:7: override_dh_auto_build] Error 25
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
make: *** [debian/rules:4: binary] Error 2
dpkg-buildpackage: error: debian/rules binary subprocess failed with exit status 2
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