Re: ghci 7.4.1 no longer loading .o files?

On 21/02/2012 04:57, Evan Laforge wrote:

On Mon, Feb 20, 2012 at 8:33 PM, Evan Laforge wrote:

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On Mon, Feb 20, 2012 at 1:14 AM, Eugene Crosser wrote:

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On 02/20/2012 10:46 AM, Evan Laforge wrote:

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Is there something that changed in 7.4.1 that would cause it to decide to interpret .hs files instead of loading their .o files? E.g.:

I don't *know* but could this have anything to do with this?

http://hackage.haskell.org/trac/ghc/ticket/5878

Indeed it was, I initially thought it wasn't because I wasn't using flags for either, but then I remember ghci also picks up flags from ~/.ghci. Turns out I was using -fno-monomorphism-restriction because that's convenient for ghci, but not compiling with that.

I guess in the case where an extension changes the meaning of existing code it should be included in the fingerprint and make the .o not load. But my impression is that most ExtensionFlags let compile code that wouldn't compile without the flag. So shouldn't it be safe to exclude them from the fingerprint?

Either way, it's a bit confusing when .ghci is slipping in flags that are handy for testing, because there's nothing that tells you *why* ghci won't load a particular .o file.

After some fiddling, I think that -osuf should probably be omitted from the fingerprint. I use ghc -c -o x/y/Z.hs.o. Since I set the output directly, I don't use -osuf. But since ghci needs to be able to find the .o files, I need to pass it -osuf. The result is that I need to pass ghc -osuf when compiling to get ghci to load the .o files, even though it doesn't make any difference to ghc -c, which is a somewhat confusing requirement.

In fact, since -osuf as well as the -outputdir flags affect the location of the output files, I'd think they wouldn't need to be in the fingerprint either. They affect the location of the files, not the contents. If you found the files it means you already figured out what you needed to figure out, it shouldn't matter *how* you found the files.

And doesn't the same go for -i? Isn't it valid to start ghci from a different directory and it should work as long as it's able to find the files to load?

I agree - I'll omit all these flags from the recompilation check in 7.4.2. Cheers, Simon