[GHC] #16308: testsuite driver is sensitive to registration of multiple boot package versions

[GHC]

#16308: testsuite driver is sensitive to registration of multiple boot package
versions
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           Reporter:  bgamari        |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.6.3
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 Currently `testsuite/tests/Makefile` generates the `--rootdir` flags to be
 passed by `runtests.py` by looking at the output of `ghc-pkg list`. In the
 case that the user has recently bumped their submodules this list may
 contain multiple versions of the same package. This will then result in
 the same `library/$LIB/tests` directory being passed to the testsuite
 driver more than once. The testsuite driver will then squawk a "There are
 multiple tests with this name" warning. It took a few minutes for Simon
 and I to work out why this was.

 We should do better here (at least in Hadrian). Either by:

  * Teaching the testsuite driver to deduplicate the `--rootdir` list
  * Using a more robust source for the list of tested packages

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16308>
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