How do you merge two Git repositories?

Question

Consider the following scenario:

I have developed a small experimental project A in its own Git repo. It has now matured, and I\'d like A to be part of larger projec

Answer 1

If you're trying to simply glue two repositories together, submodules and subtree merges are the wrong tool to use because they don't preserve all of the file history (as people have noted on other answers). See this answer here for the simple and correct way to do this.