The problem is dependency which changed with any of the git-tracked content changing. My interpretation: 1. Original author writes a program using Lua. Author

The problem is dependency which changed with any of the git-tracked content changing. My interpretation: 1. Original author writes a program using Lua. Author downloads the latest version of Lua into his system and includes and links it. Note that Lua is not checked into his version control system nor does he note the used version. 2. Lua upstream does a backwards incompatible change 3. Author extends his local (old) copy of Lua Result: An external dev will find no combination of Lua version and program revision which compiles. The original author seems to have lost his local modified Lua version. You can probably spot various mistakes an experience software developer would avoid. The interesting point is that Go seems to encourage Step 1 nonetheless?