0.3.1 ERROR: dangling backslash

[dhoegh]

I have just updated to 0.3.1 and when I am in shell mode the console auto completes with \ on windows which gives an error, see log:

shell> cd Do
Documents\ Downloads\
julia> versioninfo()
Julia Version 0.3.1
Commit c03f413* (2014-09-21 21:30 UTC)
Platform Info:
  System: Windows (x86_64-w64-mingw32)
  CPU: Intel(R) Core(TM) i7-2630QM CPU @ 2.00GHz
  WORD_SIZE: 64
  BLAS: libopenblas (USE64BITINT DYNAMIC_ARCH NO_AFFINITY Sandybridge)
  LAPACK: libopenblas
  LIBM: libopenlibm
  LLVM: libLLVM-3.3

[ivarne]

Might have been introduced in #8122?
cc @tkelman and @lucasb-eyer

[tkelman]

I suspect it's the joinpath(file,"") from 8a0f6aa, may want to just replace that with file * "/". Will test that later this afternoon. You don't mean it's erroring and closing the repl, do you? That's what was happening before that commit.

[dhoegh]

No, it just auto completes with backlash and when you hit enter then the error occurs.

[lucasb-eyer]

Could you show us the actual error message, and give detailed steps to reproduce?

[dhoegh]

If you stand in your home dir write:
Dow # hit tab, then it auto completes to:
Downloads
hit enter then you get error.

[lucasb-eyer]

Adding the trailing slash for folders is by design, so one can keep tabbing further down the hierarchy. I think that behavior was the same before my commits #8122 ; has this not happened before 3.1?

On linux, cd foo/ is not a problem, so I guess it's a windows thing, don't have Julia there though.

[dhoegh]

The problem is that it's a backlash and yes I think it's a windows problem.

[tkelman]

@dhoegh please try to report the entire error message in the future whoops it's in the subject, sorry I'm blind. I built release-0.3, it looks like the error is "dangling backslash" which makes sense. If you manually type a second backslash then additional tab-completion to deeper subfolders works fine. Although joinpath("Downloads","") returns "Downloads\\" so maybe something is getting double-escaped somewhere?

[dhoegh]

I will do that, but the actual problem is that it auto completes with backlash, 0.3 auto completes with frontslash which is the correct behavior.

[tkelman]

0.3.0 also crashes the repl if you do C:\\<tab>, so we shouldn't directly revert anything. I'm not sure which commit changed the behavior from front slash to backslash. Arguably for Windows the correct behavior would be completing with double-backslash, but forward slash should work too in the vast majority of cases.

[dhoegh]

I would agree that the correct behavior would be to have backlash between folders but it does not work when the repl is in shell mode.

[lucasb-eyer]

Could the reason for double-escape be that I changed matches' type from ByteString[] to UTF8String[] in 47d3ecf? If so, that'd be very "magic" behavior and we should add a comment when switching back to ByteString[].

[dhoegh]

I have looked more into the problem and i have come so far that it is in the Base.REPLCompletions.shell_completions function se the following.
In Julia 0.3 i get:

julia> Base.REPLCompletions.shell_completions("cd Docume",7)
(ASCIIString["Documents/"],4:7,true)
julia> Base.REPLCompletions.complete_path("Docume")
1-element Array{Union(ASCIIString,UTF8String),1}:
 "Documents\\"

0.3 completes with a front slash and 0.4 does this:

julia> Base.REPLCompletions.shell_completions("cd Docume",7)
(UTF8String["Documents\\"],4:7,true)
julia> Base.REPLCompletions.complete_path("Docume",6)
(UTF8String["Documents\\"],1:6,true)

The problem here is not only that it only completes with one backslash but also the following behavior:

cd Documents\\<tab><tab>

Then I get the completion equivalent to C:\\ which is not the right behavior. So my suggestion would be to role it back to complete with front slash for now what do you guy's think?

[dhoegh]

Base.REPLCompletions.shell_completions function was changed completing with backslash in 47d3ecf, could we role back to the old version or can we change the new to complete with front slash @lucasb-eyer?

[lucasb-eyer]

(sorry for the silence, was busy. Commenting in your PR)