Previously if a cobra user didn't specify an explicit .Date header, the
current time would be included in all of the generated man pages each
time they were built. This causes an issue for reproducible builds,
since each re-build of a package that includes the man pages will have
different times listed in the man pages.
To fix this, add support for SOURCE_DATE_EPOCH (which is a standardised
packaging environment variable, designed to be used specifically for
this purpose[1]).
[1]: https://reproducible-builds.org/specs/source-date-epoch/
Signed-off-by: Aleksa Sarai <asarai@suse.de>
Just like the last commit, but now for manpages.
genMan still works with a buffer and returns []byte instead of working
directly with an io.Writer. This is because, in turn, md2man takes byte
slices instead of readers and writers.
Wrapping genMan around a writer is unnecessary especially since it's not
an exported function, and also because we'd still need a buffer to get
the output bytes.
* Move man_docs and md_docs into new doc pkg
* Replace *bytes.Buffer with io.Writer
* Replace c == cmd.helpCommand with c.IsHelpCommand()
* Remove redundant len(children) == 0 check in HasSeeAlso
* Duplicate test setup for doc generation
