Reproducing bugs without Stack

Eric Crockett ecrockett0 at
Sun Jan 20 05:08:14 UTC 2019


I use Stack for all of my Haskell development. I recently ran into several
bugs, which I suspected to be GHC bugs. In the process of creating new
tickets, I noticed a banner reading "*Please try to provide reproduction
instructions which do not require "Stack"." *The request is reasonable to
help weed out bugs in Stack itself, but I could use some advice on how to
do that.

In particular, I'm having trouble reproducing bugs related to profiling.
For example, #16182 <> is
about runtime crashes with the -hr profiling option. This was clearly a GHC
bug rather than a problem with stack, yet I have so far been unable to
produce the bug without Stack. Similarly, for #16166
<>, I filed the ticket, then
after failing to reproduce the bug with cabal, assumed it must be a stack
bug. Fortunately, RyanGlScott noticed and was able to confirm that it is in
fact a GHC bug. Ryan explained that my problem reproducing with cabal is
due to differences in the profiling options used by stack and cabal.

In summary, it would be helpful to have some instructions on how to take a
bug produced using Stack to one produced without. For example, if `stack
build [--profile] foo` produces a compile bug, how should I use cabal to
definitively determine if the bug is a problem with Stack or GHC?
Presumably it would begin with `cabal sandbox init`. Are there special
options to put in the cabal.config file so that cabal uses the same
profiling options as stack? Will those options be used when building all

Eric Crockett
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