[GHC] #16201: ghci063 failing on Darwin

[GHC]

#16201: ghci063 failing on Darwin
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        Reporter:  bgamari           |                Owner:  (none)
            Type:  bug               |               Status:  patch
        Priority:  highest           |            Milestone:  8.8.1
       Component:  Compiler          |              Version:  8.6.3
      Resolution:                    |             Keywords:  ci-breakage
Operating System:  MacOS X           |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |  https://gitlab.haskell.org/ghc/ghc/merge_requests/440
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Comment (by Vladislav Zavialov <vlad.z.4096@…>):

 In [changeset:"f320f3b2f2f421af41b8f7588529ed46bbe6ccf3/ghc" f320f3b/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="f320f3b2f2f421af41b8f7588529ed46bbe6ccf3"
 Fix the ghci063 test on Darwin (Trac #16201)

 We use "touch -r" to set modification timestamps, which leads to precision
 loss
 on Darwin. For example,

    before: 2019-02-25 01:11:23.807627350 +0300
    after:  2019-02-25 01:11:23.807627000 +0300
                                      ^^^
 This means we can't trick GHCi into thinking the file hasn't been changed
 by
 restoring its old timestamp, as we cannot faithfully restore all digits.

 The solution is to nullify the insignificant digits before the first :load
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16201#comment:8>
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