For the record: I never meant to walk the entire cwd, only source
While I get the general idea of 'never walk directory trees', in the end
#11418: Suggest correct spelling when module is not found because of typo -------------------------------------+------------------------------------- Reporter: syd | Owner: Type: feature request | Status: new Priority: lowest | Milestone: Component: Compiler | Version: Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect | Unknown/Multiple warning at compile-time | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by svenpanne): Replying to [comment:28 syd]: directories. Hmm, what is a "source directory" then? And what is the exact use case for the feature? I'm a bit lost in this long ticket by now... For anything non-trivial, most people will probably use cabal or stack, anyway (and even for trivial stuff it's often quicker to do a "cabal init" or "stack new" than to fiddle around with epic GHC command lines). that is what you're doing anyway. Hmmm, unless things have changed, I don't think GHC walks the directory tree somehow. Trying to open a file in a few(!) directories is a fundamentally different operation than walking a directory hierarchy. If you try to open another file a tiny bit later, the OS will probably still have the relevant parts of the file system in its cache, so somehow your proposal is moving the caching strategy from the OS to user land, something which is rarely worthwhile and is tricky to get right and perform well.
In directories that only contain the source files, this approach would only reduce the amount of files opened. [...]
Your proposal actually trades off trying to open several files from probably OS-cached directories against a single retrieval of a potentially large directory hierarchy. You probably save a few context switches, but lose in most other aspects. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11418#comment:29 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler