Re: Reproducibility of Qt packages

[Maxim Cournoyer]

Hello Marius!

Marius Bakke <address@hidden> writes:

> Hi Maxim,
>
> I noticed this nice commit:
>
> address@hidden writes:
>
>> commit a4f1a7e2db22cd028fb514846c2791928b8734d3
>> Author: Maxim Cournoyer <address@hidden>
>> AuthorDate: Wed Apr 15 02:03:26 2020 -0400
>>
>>     gnu: linphoneqt: Fix reproducibility issue and improve description.
>>     
>>     * gnu/packages/linphone.scm (linphoneqt)[phases]: Rename the 'patch 
>> phase to
>>     'set-version-string, and use the version variable of the package in the
>>     replacement.
>>     {set-qt-rcc-source-date-override, fix-cmake-error}: Add phases.
>>     [synopsis]: Explicit what the package is.
>>     [description]: Mention more useful keywords and features.
>
> [...]
>
>> +         (add-after 'set-paths 'set-qt-rcc-source-date-override
>> +           (lambda _
>> +             ;; This fixes a reproducibility problem where the Qt Resource
>> +             ;; Compiler (RCC) includes timestamp of the its source files
>> +             ;; (see: https://reproducible-builds.org/docs/
>> +             ;;       deterministic-build-systems/#cmake-notes)
>> +             (setenv "QT_RCC_SOURCE_DATE_OVERRIDE" "1")
>> +             #t))
>
> Would it make sense to add this variable directly in qt-build-system (or
> maybe even patch Qt to make it the default)?

I thought about this, but according to
https://reproducible-builds.org/docs/deterministic-build-systems/#cmake-notes,
Qt version 5.13 honors SOURCE_DATE_EPOCH which we already set, so I
think it's better to move to this version as soon as possible instead.

Maxim