path contains duplicate entry: 'jars/libraries/com/google/code/gson/gson/2.8.0/gson-2.8.0.jar' for project 'Client' mcp 1.12.2

Question

i have decompiled minecraft, but when i run i get this:
path contains duplicate entry: \'jars/libraries/com/google/code/gson/gson/2.8.0/gson-2.8.0.jar\' for project \'Cl