[GHC] #10171: runghc has problem when the argument list is too big

[GHC]

#10171: runghc has problem when the argument list is too big
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        Reporter:  redneb            |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  low               |               Milestone:
       Component:  Compiler          |                 Version:  7.11
      Resolution:                    |                Keywords:
Operating System:  POSIX             |            Architecture:
 Type of failure:  Runtime crash     |  Unknown/Multiple
      Blocked By:                    |               Test Case:
 Related Tickets:  #7980             |                Blocking:
                                     |  Differential Revisions:
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Changes (by rwbarton):

 * related:   => #7980


Comment:

 Usually there is a limit on the size of an individual argument as well as
 a (much larger) limit on the total size of all the arguments. So the
 `':main ["arg1", "arg2"]'` argument can end up exceeding the former limit
 even when the original command was nowhere near either limit. See #7980.

 This may be what is going wrong for you too (despite the wording of the
 error message "Argument ''list'' too long"; note that it is the same in
 the linked ticket).

 The way to fix this would be to preserve the original argument list as a
 suffix of the argument list to ghc, with something like

 {{{
 -ignore-dot-ghci -x hs -e ':set prog "script.hs"' -e ':main' script.hs
 --with-remaining-arguments arg1 arg2
 }}}

 That still leaves the original issue, though.

 If `xargs` really leaves ''no'' extra room in the argument list size, I
 would consider that more than a bit crazy. Recall also that `runhaskell`
 is a symbolic link to `runghc` and the user could invoke the latter
 directly, which gives you 4 fewer characters to work with. For that
 matter, the user could invoke `runghc` through another symlink named `r`,
 and then you are really stuck! For this reason I think playing games with
 the lengths of GHC's options is a bit misguided.

 It may be the simplest solution to both issues to have `runghc` simply
 invoke the GHC API directly (ideally reusing the code of `ghci`) rather
 than launching a separate `ghc` process. Now that we have dynamic
 libraries, the extra binary size is no concern right? :)

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10171#comment:2>
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