How Git Works

• Current repository changes
  
• To understand we will be using plumbing commands

git cat-file -t <commit-id>
git cat-file -p <commit-id>

• Commit is an SHA-1 hash of
  • parent
  • author
  • message
  • date time
  • contents
• Git reference objects
  • branch
  • tag
• What is branch in git?
  • Branch is a reference object which points to some commit id, Branch points to a new commit id when a new commit happens
• What is tag in git?
  • tag is a reference object which points to some commit id and doesnot move with new commits
• Lets figure from latest commit on develop branch 3306f46
  
• tree in git represents folder/directory and blob/object represents file
• lets view contents of tree in latest commit
  

Merging Changes between Branches

• Consider the following history
  
• we need changes from develop branch into master branch
• now checkout to master and then execute merge

git checkout master
git merge develop

• When git cannot merge changes due to different content in same lines it will raise conflicts.
  
• After fixing conflicts, add the changes and commit them which leads to creation of new commit with two parents
  
  
• This is called as three way merge
• Consier the following
  
• We need to have all the changes in develop branch into master
  
  

Terms

• Hashing