DevOps Classroom Series – 21/Nov/2021

Git reset hard vs soft vs mixed

• Git reset –soft to fourth commit
• Git Reset hard vs soft vs mixed

Git Branching

• While building any application we might need parallel versions for multiple use cases

  • Experimenting with changes (POCs)
  • Handling multiple versions
  • Handling multiple customers

• When in git repository you are always in a branch and the default branch is master.

• To view all the branches in your local repo

• Lets create a new branch:

  • we can create the new branch using git branch <branch-name> a new branch will be create from the current HEAD and Branch (master)
  • Lets create a branch called as REL_1.0 => git branch REL_1.0
  • Even after you create the branch the HEAD will be pointing towards master i.e. working tree still represents master
  • To be in REL_1.0 branch we need to explicitly execute the command git checkout REL_1.0
  • Now lets make a commit in REL_1.0 branch
  • Now lets try to move to master branch git checkout master
  • If we want to create a new branch and move the HEAD to the new branch then we need to execute git checkout -b <new-branch-name>. SO Lets create REL_1.1 and move the head to the REL_1.1
  • Now lets create a commit in REL_1.1

• Now lets make two more commits on REL_1.0 branch

• To view the history lets use this command git log --graph --decorate --pretty=oneline --abbrev-commit

• Merging Branches:

  • Now lets assume that our work in REL_1.0 branch is done and we want to bring back the changes to master branch
  • The current state of the branches are as shown below
  • Now if we want the history or all the commits done in REL_1.0 also to be included in master (bring back all the changes), then if my master branch looks at the latest commit of REL_1.0 branch then we will still have two branches (master, REL_1.0) and the history will be retained and all the changes also will be retained
  • This kind of scenario is called as Fast-Forward Merge
  • Now lets assume our master branch is as shown below, in this case Fast-Forward will not work
  • So the classical merge will happen
  • Now lets come back to reality. The current history looks as shown below
  • Now to merge from REL_1.0 to master, move to Master and execute git merge REL_1.0
  • Now lets assume we have done the completed the change in REL_1.1 branch and we need to bring back the changes to master, so we need to merge the changes.
  • When we merge the code, we might get merge conflicts, It is upto the user who is merging to resolve conflicts.
  • Now since we got the conflict we have two options
    • undo the merge
    • fix the merge:
      • current situation:
      • Open the conflicted files
      • After fixing conflicts and saving the files execute git add . && git commit
      • Now execute esc+:wq+Enter key combination
      • Now look at history
      • Our version graph