[GHC] #16242: Hadrian is too aggressive in rebuilding

[GHC]

#16242: Hadrian is too aggressive in rebuilding
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        Reporter:  goldfire          |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Build System      |              Version:  8.6.3
  (Hadrian)                          |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by snowleopard):

 > I think the real root of the problem here is that it's very easy to
 forget adding `--freeze1` to the command line. Perhaps having a way to
 persist this setting would alleviate much of the pain associated with
 unintended rebuilds.

 We could indeed make it possible to set `--freeze1`, or more generally
 `--skip` any set of dependencies, by modifying the default build flavour
 in `UserSettings.hs`.

 This requires the user to make some initial changes in their
 `UserSettings` file, but after that any `build` command will rebuild
 exactly what they asked.

 Does this sound like the right approach? I think implementation-wise, this
 is quite easy.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16242#comment:5>
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