[debhelper-devel] Bug#894220: debhelper: In some conditions, dh loads .so outside build environment

[Xavier Guimard]

Package: debhelper
Version: 11.1.5
Severity: normal

When building libdbi-perl_1.641 with libdbi-perl_1.640 installed, build
fails because DBI.so is loaded from system tree instead of build
environment. But when launching only 'dh build', all works. I didn't
succeed to find where is the problem.

Details:
 - build tree cloned from https://salsa.debian.org/perl-team/modules/packages/libdbi-perl
   commit da93eb34 (upstream version 1.641)
 - libdbi-perl_1.640 installed on the system
 - pdebuild -> OK
 - debuild -> fail: DBI object version 1.640 does not match bootstrap parameter
                    1.641 at /usr/lib/x86_64-linux-gnu/perl/5.26/DynaLoader.pm
		    line 204
 - gbp buildpackage -> fail (same message)
 - dh_quilt_patch && dh build -> OK
 - pdebuild with libdbi-perl added to Build-Depends: OK

Some debugging shows that
/usr/lib/x86_64-linux-gnu/perl5/5.26/auto/DBI/DBI.so is loaded by
bootstrap() function (DynaLoader.pm) even if @INC is well set

After IRC discussion (#debian-perl), Jonas asked me to open this issue

-- System Information:
Debian Release: buster/sid
  APT prefers testing
  APT policy: (600, 'testing'), (50, 'unstable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.14.0-3-amd64 (SMP w/2 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8), LANGUAGE= (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages debhelper depends on:
ii  autotools-dev            20180224.1
ii  dh-autoreconf            17
ii  dh-strip-nondeterminism  0.040-1
ii  dpkg                     1.19.0.5
ii  dpkg-dev                 1.19.0.5
ii  file                     1:5.32-2
ii  libdpkg-perl             1.19.0.5
ii  make                     4.1-9.1
ii  man-db                   2.8.2-1
ii  perl                     5.26.1-5
ii  po-debconf               1.0.20

debhelper recommends no packages.

Versions of packages debhelper suggests:
pn  dh-make  <none>
pn  dwz      <none>

-- no debconf information