How is git validation implemented?

Question

At startup git checkout, the mergebase of the old HEADand the new HEADcan be arbitrarily far back. A naive implementation would be to linearly apply each diff, but the operation is instantaneous.

I have a hunch that it could be implemented with something like skiplisty for intermediate diff caching, but this is just an assumption.

Does anyone know how this is implemented? Thank you :)

Answer 1

You have a good example of how verification (in principle) is implemented in the git javascript implementation (as an exercise) of Mary Rose Cook's Gitlet .

checkout :

• checkout() , HEAD, ref.
  ref .
• .
• , ref .
• , , .
• , ref - . , , ref - , HEAD .
• , .
  , .
  - , .
• .
• ref , , .
• . .
• HEAD.
  , HEAD.
  , HEAD.
• .
• .

, ( Git), , .

, GitMinutes # 31: Mary Rose Cook on Gitlet .