Re: [GHC] #1012: ghc panic with mutually recursive modules and template haskell
#1012: ghc panic with mutually recursive modules and template haskell ---+ Reporter: guest | Owner: Type: bug | Status: new Priority: low | Milestone: 7.2.1 Component: Template Haskell |Version: 6.8.2 Resolution:| Keywords: Testcase: TH_import_loop| Blockedby: Difficulty: Unknown | Os: Unknown/Multiple Blocking:| Architecture: Unknown/Multiple Failure: None/Unknown | ---+ Changes (by dleuschner): * cc: leuschner@… (added) * failure: = None/Unknown Comment: Just a note: Of course this is not an important bug/limitation. It would be still nice if it would just work. It took me some time to realise what the problem is, find this bug report and the section in the manual and reorganise the code to accomodate for the limitation. Before that I did several clean/rebuild, rebuild without make -j cycles to be sure that it's not a problem with the build system. It's a bit unexpected because normally GHC just does everything I want (and even more). :-) -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1012#comment:22 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler ___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: [GHC] #1012: ghc panic with mutually recursive modules and template haskell
#1012: ghc panic with mutually recursive modules and template haskell -+-- Reporter: guest |Owner: Type: bug | Status: reopened Priority: normal|Milestone: 6.12 branch Component: Template Haskell | Version: 6.8.2 Severity: normal| Resolution: Keywords:| Difficulty: Unknown Testcase: TH_import_loop| Os: Unknown/Multiple Architecture: Unknown/Multiple | -+-- Changes (by igloo): * milestone: 6.10 branch = 6.12 branch -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1012#comment:17 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: [GHC] #1012: ghc panic with mutually recursive modules and template haskell
#1012: ghc panic with mutually recursive modules and template haskell --+- Reporter: guest | Owner: Type: bug | Status: reopened Priority: normal| Milestone: 6.10 branch Component: Template Haskell |Version: 6.8.2 Severity: normal| Resolution: Keywords:| Difficulty: Unknown Testcase: TH_import_loop| Architecture: Multiple Os: Multiple | --+- Changes (by simonpj): * milestone: _|_ = 6.10 branch Comment: Fair enough. I have taken a little look at this, based on fons's suggestion ``every module M that depends on a module C in a cycle, but is not a member of that cycle, should have an implicit dependency on each of the modules C1.. Cn in the cycle.``. Yes, I think that would not be too hard to do. There are two places to think about: * `ghc --make`: When deciding the up-sweep order, first do a SCC analysis finding strongly connected components of modules, and top-sort those components. Then linearise each component. That gives a linear order that respects fons's suggestion. * `ghc -M`: similar story, but less neat. We have to emit lots of extra dependencies in the `makefile`, so that M depends on C1..Cn. Not very hard, but more than an hours work. Let's do it for 6.10. Simon -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1012#comment:14 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: [GHC] #1012: ghc panic with mutually recursive modules and template haskell
#1012: ghc panic with mutually recursive modules and template haskell --+- Reporter: guest | Owner: Type: bug | Status: reopened Priority: normal| Milestone: _|_ Component: Template Haskell |Version: 6.8.2 Severity: normal| Resolution: Keywords:| Difficulty: Unknown Testcase: TH_import_loop| Architecture: Multiple Os: Multiple | --+- Changes (by igloo): * status: closed = reopened * resolution: fixed = * milestone: 6.8 branch = _|_ Comment: I agree that it is still a bug, but I've put it back in the _|_ milestone as it's easy to work-around, and I assume that if it was trivial to fix then SPJ would have done so. -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1012#comment:13 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: [GHC] #1012: ghc panic with mutually recursive modules and template haskell
#1012: ghc panic with mutually recursive modules and template haskell
--+-
Reporter: guest | Owner:
Type: bug | Status: closed
Priority: normal| Milestone: 6.8 branch
Component: Template Haskell |Version: 6.8.2
Severity: normal| Resolution: fixed
Keywords:| Difficulty: Unknown
Testcase: TH_import_loop| Architecture: Multiple
Os: Multiple |
--+-
Changes (by simonpj):
* status: reopened = closed
* resolution: = fixed
Comment:
Simon is right: B.hs depends on C.hs, which depends on A.hs-boot. I think
it's quite accidental that A happens to be compiled before B in your
curiously enough case, but after B in your original case.
All you need do is to make B depend on A, thus
{{{
{-# LANGUAGE TemplateHaskell #-}
module ModuleB where
import ModuleC
import ModuleA
$(nothing)
}}}
and it all works fine. Use -v to see the compilation order.
I will clarify the documentation, thus:
You can only run a function at compile time if it is imported from
another module ''that is not part of a mutually-recursive group of modules
that includes the module currently being compiled''. Furthermore, all of
the modules of the mutually-recursive group must be reachable by non-
SOURCE imports from the module where the splice is to be run.
{{{
Fri Jan 4 12:19:39 GMT 2008 [EMAIL PROTECTED]
* Document SOURCE pragma; clarify TH behavior for
mutually-recurive modules (Trac #1012)
}}}
It's not clear to me how to improve the error message, at least not
without adding more plumbing to say I'm in a Template Haskell splice.
Let's see if it happens again.
Meanwhile I'll close the bug.
Simon
--
Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1012#comment:11
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Re: [GHC] #1012: ghc panic with mutually recursive modules and template haskell
#1012: ghc panic with mutually recursive modules and template haskell
--+-
Reporter: guest | Owner:
Type: bug | Status: closed
Priority: normal| Milestone: 6.8 branch
Component: Template Haskell |Version: 6.8.2
Severity: normal| Resolution: fixed
Keywords:| Difficulty: Unknown
Testcase: TH_import_loop| Architecture: Multiple
Os: Multiple |
--+-
Comment (by fons):
Replying to [comment:11 simonpj]:
Simon is right: B.hs depends on C.hs, which depends on A.hs-boot. I
think it's quite accidental that A happens to be compiled before B in your
curiously enough case, but after B in your original case.
All you need do is to make B depend on A, thus
{{{
{-# LANGUAGE TemplateHaskell #-}
module ModuleB where
import ModuleC
import ModuleA
$(nothing)
}}}
and it all works fine. Use -v to see the compilation order.
I finally managed to solve the problem turning around the circular
dependencies of my project (tranforming the SOURCE imports of the loop in
normal onces and vice versa). However, the workaround suggested by Simon
should work as you said.
Meanwhile I'll close the bug.
As far as I understand, ghc's dependency analysis could be improved
(otherwise a workaround would not be needed). I don't personally think
this bug should be closed and include it as a limitation in the docs
before considering simonmar's proposal, that is:
''What's happening is that the dependency analysis isn't figuring out that
the real ModuleA must be compiled before ModuleB. I think the solution is
something along the lines of: every module that depends on a module in a
cycle, but is not a member of that cycle, should have an implicit
dependency on each of the modules in the cycle. ''
--
Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1012#comment:12
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Re: [GHC] #1012: ghc panic with mutually recursive modules and template haskell
#1012: ghc panic with mutually recursive modules and template haskell --+- Reporter: guest | Owner: Type: bug | Status: reopened Priority: normal| Milestone: _|_ Component: Template Haskell |Version: 6.8.2 Severity: normal| Resolution: Keywords:| Difficulty: Unknown Testcase: TH_import_loop| Architecture: Multiple Os: Multiple | --+- Comment (by simonmar): Since `ModuleB` is outside the `ModuleA/ModuleC` loop, it can import `ModuleA` without creating any new loops, and I bet this will work around the problem and get you unblocked. What's happening is that the dependency analysis isn't figuring out that the real `ModuleA` must be compiled before `ModuleB`. I think the solution is something along the lines of: every module that depends on a module in a cycle, but is not a member of that cycle, should have an implicit dependency on each of the modules in the cycle. -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1012#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: [GHC] #1012: ghc panic with mutually recursive modules and template haskell
#1012: ghc panic with mutually recursive modules and template haskell --+- Reporter: guest | Owner: Type: bug | Status: reopened Priority: normal| Milestone: 6.8 branch Component: Template Haskell |Version: 6.8.2 Severity: normal| Resolution: Keywords:| Difficulty: Unknown Testcase: TH_import_loop| Architecture: Multiple Os: Multiple | --+- Changes (by simonmar): * milestone: _|_ = 6.8 branch -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1012#comment:10 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: [GHC] #1012: ghc panic with mutually recursive modules and template haskell
#1012: ghc panic with mutually recursive modules and template haskell +--- Reporter: guest | Owner: Type: bug | Status: reopened Priority: normal | Milestone: _|_ Component: Compiler|Version: 6.8.2 Severity: normal | Resolution: Keywords: | Difficulty: Unknown Testcase: TH_import_loop | Architecture: Multiple Os: Multiple| +--- Changes (by fons): * version: 6.6 = 6.8.2 * type: merge = bug -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1012#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: [GHC] #1012: ghc panic with mutually recursive modules and template haskell
#1012: ghc panic with mutually recursive modules and template haskell --+- Reporter: guest | Owner: Type: bug | Status: reopened Priority: normal| Milestone: _|_ Component: Template Haskell |Version: 6.8.2 Severity: normal| Resolution: Keywords:| Difficulty: Unknown Testcase: TH_import_loop| Architecture: Multiple Os: Multiple | --+- Changes (by fons): * component: Compiler = Template Haskell -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1012#comment:8 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: [GHC] #1012: ghc panic with mutually recursive modules and template haskell
#1012: ghc panic with mutually recursive modules and template haskell
+---
Reporter: guest | Owner:
Type: merge | Status: reopened
Priority: normal | Milestone: _|_
Component: Compiler|Version: 6.6
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Testcase: TH_import_loop | Architecture: Multiple
Os: Multiple|
+---
Changes (by fons):
* status: closed = reopened
* resolution: fixed =
Comment:
Don't know if this deserves its own ticket but it seems that ghci (or ghc
--make) fails when running a compile-time function imported from a
mutually-recursive group of modules which _doesn't_ include the module
currently being compiled.
ModuleA.hs-boot
{{{
module ModuleA
}}}
ModuleA.hs
{{{
module ModuleA where
import ModuleC
}}}
ModuleC.hs
{{{
odule ModuleC where
import Language.Haskell.TH
import {-# SOURCE #-} ModuleA
nothing = return [] :: Q [Dec]
}}}
ModuleB.hs (makes use of a function of C but is _not_ included in the
group of recursive modules)
{{{
{-# LANGUAGE TemplateHaskell #-}
module ModuleB where
import ModuleC
$(nothing)
}}}
{{{
$ ghci ModuleB.hs
GHCi, version 6.8.1: http://www.haskell.org/ghc/ :? for help
Loading package base ... linking ... done.
[1 of 4] Compiling ModuleA[boot]( ModuleA.hs-boot, interpreted )
[2 of 4] Compiling ModuleC ( ModuleC.hs, interpreted )
[3 of 4] Compiling ModuleB ( ModuleB.hs, interpreted )
module main:ModuleA cannot be linked; it is only available as a boot
module
}}}
Furthermore, it would be really useful if the error message indicated the
compilation failed due to Template Haskell. (It took me a while to figure
out why it was caused)
--
Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1012#comment:5
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Re: [GHC] #1012: ghc panic with mutually recursive modules and template haskell
#1012: ghc panic with mutually recursive modules and template haskell
+---
Reporter: guest | Owner:
Type: merge | Status: reopened
Priority: normal | Milestone: _|_
Component: Compiler|Version: 6.6
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Testcase: TH_import_loop | Architecture: Multiple
Os: Multiple|
+---
Comment (by fons):
curiously enough compiling the following module doesn't cuase any
problems.
Main.hs
{{{
module Main where
import ModuleB
main = return ()
}}}
{{{
$ ghc --make Main.hs
[1 of 5] Compiling ModuleA[boot]( ModuleA.hs-boot, ModuleA.o-boot )
[2 of 5] Compiling ModuleC ( ModuleC.hs, ModuleC.o )
[3 of 5] Compiling ModuleA ( ModuleA.hs, ModuleA.o )
[4 of 5] Compiling ModuleB ( ModuleB.hs, ModuleB.o )
Loading package base ... linking ... done.
Loading package array-0.1.0.0 ... linking ... done.
Loading package packedstring-0.1.0.0 ... linking ... done.
Loading package containers-0.1.0.0 ... linking ... done.
Loading package pretty-1.0.0.0 ... linking ... done.
Loading package template-haskell ... linking ... done.
[5 of 5] Compiling Main ( Main.hs, Main.o )
Linking Main ...
}}}
--
Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1012#comment:6
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Re: [GHC] #1012: ghc panic with mutually recursive modules and template haskell
#1012: ghc panic with mutually recursive modules and template haskell
+---
Reporter: guest | Owner:
Type: bug | Status: new
Priority: normal | Milestone: _|_
Component: Compiler|Version: 6.6
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Testcase: TH_import_loop | Architecture: Multiple
Os: Multiple|
+---
Comment (by simonmar):
This now gives a slightly improved error message, as a result of the fix
for #936:
{{{
[1 of 5] Compiling A[boot] ( A.hs-boot, nothing )
[2 of 5] Compiling C( C.hs, C.o )
[3 of 5] Compiling B( B.hs, B.o )
Loading package base ... linking ... done.
module main:A cannot be linked; it is only available as a boot module
}}}
Simon: please feel free to edit the error message if you can think of a
way to improve it (compiler/ghci/Linker.hs). Should we close this bug?
Perhaps document the shortcoming in the TH docs?
--
Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1012
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Re: [GHC] #1012: ghc panic with mutually recursive modules and template haskell
#1012: ghc panic with mutually recursive modules and template haskell +--- Reporter: guest | Owner: Type: merge | Status: new Priority: normal | Milestone: _|_ Component: Compiler|Version: 6.6 Severity: normal | Resolution: Keywords: | Difficulty: Unknown Testcase: TH_import_loop | Architecture: Multiple Os: Multiple| +--- Changes (by simonpj): * type: bug = merge Comment: I've updated the docs. Ian, please merge. Wed Jan 31 09:14:51 GMT 2007 [EMAIL PROTECTED] * Add note about Template Haskell and mutual recursion Simon -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1012 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: [GHC] #1012: ghc panic with mutually recursive modules and template haskell
#1012: ghc panic with mutually recursive modules and template haskell +--- Reporter: guest | Owner: Type: merge | Status: closed Priority: normal | Milestone: _|_ Component: Compiler|Version: 6.6 Severity: normal | Resolution: fixed Keywords: | Difficulty: Unknown Testcase: TH_import_loop | Architecture: Multiple Os: Multiple| +--- Changes (by igloo): * resolution: = fixed * status: new = closed Comment: Merged. -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1012 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
Re: [GHC] #1012: ghc panic with mutually recursive modules and template haskell
#1012: ghc panic with mutually recursive modules and template haskell +--- Reporter: guest | Owner: Type: bug | Status: new Priority: normal | Milestone: _|_ Component: Compiler|Version: 6.6 Severity: normal | Resolution: Keywords: | Difficulty: Unknown Testcase: TH_import_loop | Architecture: Multiple Os: Multiple| +--- Changes (by igloo): * architecture: powerpc = Multiple * milestone: = _|_ * testcase: = TH_import_loop * os: MacOS X = Multiple Comment: Urk, this looks tricky. It will probably want to wait until we can use code spliced in earlier in a module in later splices in the same module. -- Ticket URL: http://hackage.haskell.org/trac/ghc/ticket/1012 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler___ Glasgow-haskell-bugs mailing list Glasgow-haskell-bugs@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-bugs
