[GHC] #10822: GHC inconsistently handles \\?\ for long paths on Windows
#10822: GHC inconsistently handles \\?\ for long paths on Windows -------------------------------------+------------------------------------- Reporter: snoyberg | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Keywords: | Operating System: Windows Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- To demonstrate what I mean first: {{{
ghc-pkg init \\?\c:\Users\michael\Desktop\some-pkg-db dir \\?\c:\Users\Michael\Desktop\some-pkg-db Volume in drive \\?\c: is Windows8_OS Volume Serial Number is CEF7-874D
ghc -package-db \\?\c:\Users\Michael\Desktop\some-pkg-db ghc: can't find a package database at \\?\c:\Users\Michael\Desktop\some-
Directory of \\?\c:\Users\Michael\Desktop\some-pkg-db 09/01/2015 09:38 AM <DIR> . 09/01/2015 09:38 AM <DIR> .. 09/01/2015 09:38 AM 40 package.cache 1 File(s) 40 bytes 2 Dir(s) 5,907,509,248 bytes free pkg-db }}} The problem: on Windows by default, paths are limited to 260 characters, which can become a real problem in practice when dealing with the standard library path hierarchy the Cabal library uses and any package with a decent name length. This was a real problem in practice, see: https://github.com/haskell/cabal/issues/2502 Windows has a workaround for this: you can prefix an absolute path with \\?\, see: https://msdn.microsoft.com/en- us/library/windows/desktop/aa365247%28v=vs.85%29.aspx#maxpath It would be very useful if such paths worked with GHC, but currently they do not. I don't yet know how deep the problem is. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10822 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#10822: GHC inconsistently handles \\?\ for long paths on Windows ---------------------------------+---------------------------------------- Reporter: snoyberg | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | ---------------------------------+---------------------------------------- Comment (by dobenour): CoreCLR ran into the same problem and fixed it by adding the {{{\\?\}}} prefix to any overlong path, after making the path absolute with the {{{GetFullPathNameW}}} function in the Windows API. For UNC paths (that begin with {{{\\}}} but not with {{{\\?\}}}), the solution is to replace {{{\\}}} with {{{\\?\UNC\}}}. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10822#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#10822: GHC inconsistently handles \\?\ for long paths on Windows ---------------------------------+---------------------------------------- Reporter: snoyberg | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | ---------------------------------+---------------------------------------- Comment (by Phyx-): The problem is that we rely on ports of POSIX applications to work. e.g. GCC, binutils etc. So even if GHC supports UNC paths. It probably wouldn't help much unfortunately. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10822#comment:2 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#10822: GHC inconsistently handles \\?\ for long paths on Windows ---------------------------------+---------------------------------------- Reporter: snoyberg | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | ---------------------------------+---------------------------------------- Comment (by ezyang): But then the best thing to do is figure out exactly what the state of short path support is in the toolchain, lobby projects to fix this, and eventually get this fixed. upstream is broken is not an excuse to throw ones hands up and give up. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10822#comment:3 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#10822: GHC inconsistently handles \\?\ for long paths on Windows ---------------------------------+---------------------------------------- Reporter: snoyberg | Owner: (none) Type: bug | Status: patch Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D4416 Wiki Page: | ---------------------------------+---------------------------------------- Changes (by Phyx-): * status: new => patch * differential: => Phab:D4416 * milestone: => 8.6.1 Comment: GCC/libiberty still needs a patch but this takes care of the Haskell side. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10822#comment:4 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
#10822: GHC inconsistently handles \\?\ for long paths on Windows
---------------------------------+----------------------------------------
Reporter: snoyberg | Owner: (none)
Type: bug | Status: patch
Priority: normal | Milestone: 8.6.1
Component: Compiler | Version: 7.10.2
Resolution: | Keywords:
Operating System: Windows | Architecture: Unknown/Multiple
Type of failure: None/Unknown | Test Case:
Blocked By: | Blocking:
Related Tickets: | Differential Rev(s): Phab:D4416
Wiki Page: |
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Comment (by Tamar Christina
#10822: GHC inconsistently handles \\?\ for long paths on Windows ---------------------------------+---------------------------------------- Reporter: snoyberg | Owner: (none) Type: bug | Status: upstream Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Windows | Architecture: Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Phab:D4416 Wiki Page: | ---------------------------------+---------------------------------------- Changes (by Phyx-): * status: patch => upstream Comment: underlying toolchain needs fixing now. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10822#comment:6 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler
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