Summary

When Bamboo checks out changes from repositories using the Windows Git.exe executable, the task fails and the following appears in the job log

java.lang.RuntimeException : com.atlassian.bamboo.plugins.stash.repository.StashRepositoryException: com.atlassian.bamboo.repository.RepositoryException: Checkout to revision <hash> has failed.command 'C:\Program Files\Git\cmd\git.exe' checkout -f master failed with code 1. Working directory was [<job working directory>]., 
stderr: error: unable to create file <filename>: Filename too long error: unable to create file

Cause

According to the msysgit wiki on GitHub and the related fix this error, Filename too long, comes from a Windows API limitation of file paths having 260 characters or fewer.

Solution

To resolve this issue, we could change the Windows default 260 character limit in the Windows registry or by configuring the core.longpaths workaround in git config.

Starting in Windows 10 (Windows Server 2016), version 1607, MAX_PATH limitations have been removed from common Win32 file and directory functions. However, you must opt-in to the new behaviour. We need to set the Windows default 260 character limit by updating the registry as mentioned here. 

Go to the registry key Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem\LongPathsEnabled (Type: REG_DWORD) must exist and be set to 1.

    New-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\FileSystem" `
   -Name "LongPathsEnabled" -Value 1 -PropertyType DWORD -Force

The git configuration setting can be used for Windows versions lower than 2016 and Windows 10.

For Git configuration run the following command from GitBash or the Git CMD prompt:

git config --system core.longpaths true

This will allow file paths of 4096 characters.

git config --global core.longpaths true