Simple handler: evaluate message before taking lock#49
Merged
hvr merged 1 commit intohaskell-hvr:masterfrom Oct 7, 2019
Merged
Simple handler: evaluate message before taking lock#49hvr merged 1 commit intohaskell-hvr:masterfrom
hvr merged 1 commit intohaskell-hvr:masterfrom
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Any news? This is a rather import bug. |
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Btw, this branch has currently Git conflicts |
Because of laziness, the `msg` string in `streamHandler` can contain arbitrary computations. In the previous state of affairs, the handler would first take the lock then `putStrLn` the message. So all the (pure) computation would happen in the critical section, and it couldn't guarantee timely release of the lock. Calling `deepseq` before the lock is taken makes sure that the locked section does only what it must do: print the string.
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Contributor
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@hvr the patch is now rebased (for the curious onlooker: the conflicts were in the cabal dependencies, and the import lists) |
Collaborator
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Thanks! This got released as part of http://hackage.haskell.org/package/hslogger-1.3.1.0 |
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Because of laziness, the
msgstring instreamHandlercan containarbitrary computations. In the previous state of affairs, the handler
would first take the lock then
putStrLnthe message. So allthe (pure) computation would happen in the critical section, and it
couldn't guarantee timely release of the lock.
Calling
deepseqbefore the lock is taken makes sure that the lockedsection does only what it must do: print the string.