Bug#932884: release.debian.org: What is the good way to update rollup ?

[Xavier Guimard <yadd@debian.org>]

Package: release.debian.org
Severity: normal

Hi all,

For the next release, we (pkg-js team) would like to update rollup. Like
many compilers, it build-depends on itself. Current version in Buster is
0.50.0, The last published upstream is 1.17.0.
We would also like to provide a Buster-backports package

Here are the upgrade constraints:

 * 0.50.0 can build any version until 0.53.3
 * 0.51.7 can build any version until 0.56.3
 * 0.56.1 can build any version until 0.65.2
 * 0.58.1 can build any version until 0.67.2
 * 0.59.1 can build any version until 1.12.0
 * 1.12.0 can build any version until 1.17.0

This needs 6 steps (at least 4 to be able to update some important JS
component with rollup 0.67.2).

There are no major break changes in rollup. At worst some function name
changed, easy to patch.

====== MAIN QUESTION ======

Is it recommended or required to provide a Buster-buildable rollup
package for next release ?

==== IF NO ====

Then we will simply update rollup step by step but there could be
problems with Buster-Backports?

==== IF YES, SECONDARY QUESTION ====

What is the best way to provide a Buster buildable package ?

In both solutions proposed, there could be buildd/autopkgtest
regressions, easy to repair however.

== ALL-IN-ONE PACKAGE ==

This could be possible by embedding 6 or 4 versions of rollup in source
package (as component) and build in 6 or 4 steps in debian/rules:

  override_dh_auto_build:
      ...
      # Step N
      cd step[N]; \
      ls -s ../../step[N-1] node_modules/rollup; \
      rollup -c
      ...
      # Last step
      ln -s ../step[Last] node_modules/rollup
      rollup -c

Regression fixes: patch rollup configuration file

== MULTIPLE PACKAGES ==

We can provide several rollup packages that build-depends on the previous
(rollup-0.52, rollup-0.67,...) with "alternative" mechanism, then rollup
becomes a virtual package.

Regression fixes: replace rollup build dependency by the good one:
rollup-0.67,...

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Cheers,
Xavier