Bug#894476: RCC: provide option to encode EPOCH timestamp

[Sune Vuorela <sune@debian.org>]

On Tuesday, April 3, 2018 9:24:58 PM CEST Chris Lamb wrote:
> I'm not /entirely/ sure what the difference is as I'm not in the
> Qt/RCC world too often these days (alas !), but why just not use
> SOURCE_DATE_EPOCH *iff* it is exported?
> 
> Normal systems simply do not have this envvar set, so there is really
> no danger of it leaking elsewhere or causing unintended side-effects.

We don't know how application users are using this.

The following is some theoretical example, that I'm quite sure could be used 
in some real world applications:

QFileInfo embeddedFile(":/foo/data.xml"); // fallback downloaded in the 
ancient past
QFileInfo systemfile("/usr/share/foo/data.xml");

if (systemfile.lastModified() > embeddedFile.lastModified())
{
   data = readFromFile(systemFile);
}
else
{
   data = readFromFile(embeddedFile);
}

If S_D_E gets used, rather than the data.xml modified date in the source, this 
will end up using the wrong file if S_D_E is newer than the system copy of the 
file.

This is not a unused databit, but a fully available piece of metadata for the 
files.

/Sune
-- 
I didn’t stop pretending when I became an adult, it’s just that when I was a 
kid I was pretending that I fit into the rules and structures of this world. 
And now that I’m an adult, I pretend that those rules and structures exist.
   - zefrank