Bug#1125000: dh-haskell: parallel build breaks reproducibility

[Jochen Sprickerhof]

Package: dh-haskell
Version: 0.6.12
Severity: normal
Tags: patch
X-Debbugs-Cc: reproducible-bugs at lists.alioth.debian.org
User: reproducible-builds at lists.alioth.debian.org
Usertags: randomness

Hi,

0.6.12 added parallel build support. This produces randomness in the
produces object files:

 │ ├── ./usr/lib/haskell-packages/ghc/lib/aarch64-linux-ghc-9.10.3-98d9/bifunctors-5.6.2-KqSUeD886HtGkwqqqyHDbB/libHSbifunctors-5.6.2-KqSUeD886HtGkwqqqyHDbB.a
│ │ │ ├── nm --print-armap {}
│ │ │ │ @@ -3983,20 +3983,20 @@
│ │ │ │                   U ghczmprim_GHCziTypes_TrNameS_con_info
│ │ │ │                   U ghczmprim_GHCziTypes_TyCon_con_info
│ │ │ │                   U ghczmprim_GHCziTypes_ZC_con_info
│ │ │ │                   U ghczmprim_GHCziTypes_ZMZN_closure
│ │ │ │                   U ghczmprim_GHCziTypes_krepzdConstraint_closure
│ │ │ │                   U ghczmprim_GHCziTypes_krepzdzt_closure
│ │ │ │                   U ghczmprim_GHCziTypes_krepzdztzmzgztzmzgzt_closure
│ │ │ │ -00000000000001e0 r idVD_str
│ │ │ │ -0000000000000220 r idVJ_str
│ │ │ │ -00000000000000d8 r idVf_str
│ │ │ │ -0000000000000118 r idVl_str
│ │ │ │ -0000000000000158 r idVr_str
│ │ │ │ -0000000000000198 r idVx_str
│ │ │ │ +00000000000000d8 r idpO_str
│ │ │ │ +0000000000000118 r idpU_str
│ │ │ │ +0000000000000158 r idq0_str
│ │ │ │ +0000000000000198 r idq8_str
│ │ │ │ +00000000000001e0 r idqe_str
│ │ │ │ +0000000000000220 r idqk_str

https://web.archive.org/web/20260108082921/https://reproduce.debian.net/arm64/api/v1/builds/96527/artifacts/202738/diffoscope

Reverting bd8f426 fixes it for me. I assume it should be enough to
binNMU all effected packages afterwards.

Cheers Jochen