Long file paths crash compilation on windows

[WebFreak001]

When I compile my dub package in a nested folder somewhere in like C:\Users\MyUsername\Development\My_D_Projects\From2016\Old\my-super-awesome-project-with-some-long-filename and I have some dependency in it like experimental_allocator it will crash with this error message:

Error: Error writing file '..\..\..\..\Roaming\dub\packages\experimental_allocator-2.70.0-b1\experimental_allocator\.dub\build\library-release-windows-x86-dmd_2071-09237FFF1A90ED11A7976B16E7AB1A89\experimental_allocator.lib'
dmd failed with exit code 1.

On Windows there is by default a file path length limit of 259 characters and either dub or dmd aren't using the extended windows paths using \\?\ which increases the length limit to 32767 characters. So Windows doesnt allow you to write the file.

Reproducable project in my case:

cd %appdata%
cd ..
cd Local\Temp
mkdir workspaced-install-636070322740907409
cd workspaced-install-636070322740907409
git clone https://github.com/Hackerpilot/DCD.git DCD
cd DCD
dub build --build=release --config=client --force

crash

[WebFreak001]

Another issue which probably has the same cause:

libdparse ~master: building configuration "library"...
Error: failed to create path to file: .dub\obj\libdparse\.dub\build\library-debug-windows-x86_64-ldc_0-DCDD4FDB2EDFDAE1509F1E37E3AAEA55\dparse.lib
no such file or directory
ldc2 failed with exit code 1.

[WebFreak001]

Workaround for Windows 10: in the registry set HKLM\SYSTEM\CurrentControlSet\Control\FileSystem LongPathsEnabled to 1 and then reboot or restart the command line and editor

[helgaros]

I think it's useful to use the long path tool program

[s-ludwig]

Optlink can surely be added to the list, too. I think the DUB fix for this should happen in Phobos. There is no reason to let this ugly piece of WinAPI design leak through to all application code in a cross platform environment.

[s-ludwig]

Just mentioning that a tiny improvement to this has been merged: #1242

[WebFreak001]

fixed by #2589