Nah, that's only the case for native packages (i.e. upstream maintained in Debian). In the normal case you've either got a .diff.gz against the tarball with the Debian changes (including debian/rules containing the configure bits) or, the newer variant, a .debian.tar.gz tarball.
But indeed the source format ties it together with the tarball instead of shipping the build instructions separately.
Posted May 17, 2011 20:54 UTC (Tue) by oak (subscriber, #2786)
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IMHO one of the more annoying omissions in Debian policy for source packages is a build target for applying patches. Currently only "good" way find out what actually is patched for given architecture is to do a build and diff the resulting sources against original ones...
Who maintains RPM? (2011 edition)
Posted May 19, 2011 19:35 UTC (Thu) by oxan (guest, #75033)
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In the new (3.0) format that problem is solved: there's a single directory, debian/patches, where all the patches are stored in a quilt-compatible format.