[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 goldfire):

 I edited `Coercion.hs`. But, even if I had edited it in a meaningful way
 (instead of just editing a comment), I'm surprised to see the whole RTS
 rebuilt. I believe that's what `LAX_DEPENDENCIES` does for `make`: it
 assumes that, just because stage-1 has changed, it doesn't mean we need to
 rebuild everything that stage-1 built. Moreover, I really just wanted to
 run a test. So, I suppose I could do that with `build --skip=stage0//*
 --skip=stage1//* test --only=xyz`. Again, that's quite a mouthful.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16242#comment:2>
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