Merge two Git repos and keep the history

Question

I want to extend on another question I had: Merge two Git repositories and keep the master history

I have succeeded in merging 2 different repo\'s into one repo. I n

Answer 1

This answer suggests a different way to use RepoB as the active repo, and still have access to RepoA history :

use git replace

# start with a regular clone of the active repo :
$ git clone RepoB

# add repoA as a remote :
$ git remote add -f history https://github.com/DimitriDewaele/RepoA

# get hash of *initial* commit on repoB :
$ git log --oneline origin/master | tail -1
abcdef Initial commit

# get hash of last commit on repoA :
$ git log --oneline history/master | head -1
12345 Merge branch 'develop'

# use 'git replace' to tell git to stitch histories in the log :
$ git replace abcdef 12345

Note : this operation is done on your machine, not on the remote repositories, so should be repeated on all new clones.

Variant :

You may push RepoA:master to RepoB under a new name (e.g : RepoB:history/master), then you can use git replace abcdef history/master, on commits which are all stored in RepoB.