diff options
authorLuke Shumaker <>2016-07-25 15:04:41 -0400
committerLuke Shumaker <>2016-07-25 15:04:41 -0400
commitd4983b7a22c6e53db647c7a89293097a6c8aa61e (patch)
parent94f3fa0d1cd24c9ef0b9c85087c962ec9e81a1fc (diff)
librefetch: add some HACKING notes
1 files changed, 25 insertions, 0 deletions
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+`librefetch` respects `SOURCE_DATE_EPOCH`[1] for reproducible builds,
+and has had this behavior from the start (though the variable name
+wasn't there from the start, that came later). But how can this be!?
+If you asked h01ger (the guy heading up reproducible builds in Debian
+and Fedora), tar needs to support `--clamp-mtime` to do this, and that
+flag wasn't in any tar implementation when librefetch came into
+existence. The flag not yet being in upstream GNU tar was for a long
+time the biggest blocker to most of upstream Debian being
+While it is a nice flag that I'm surprised wasn't added years ago,
+it's trivial to just adjust the input files first:
+ find . -exec touch --no-dereference --date=DATE -- {} +`
+Of course, `--clamp-mtime`/`--mtime` is now in upstream GNU tar. So
+librefetch supporting this is no longer impressive. But, librefetch
+still isn't using `--mtime`. Why? Well, because it uses libarchive
+`bsdtar`, not GNU tar, and bsdtar still doesn't have the flag.
+I wrote this document mostly because I expect that sometime in the
+future I'll think to myself "I should simplify the code and just use
+`--mtime`", not remembering the differences between tars.