# Rapid Team Formation Method - Git --- ## Once upon a time ... a web project ``` . ├── index.html ├── script.js └── style.css 0 directories, 3 files ``` And its git commits ``` * faace49 - Add comment line 4 (origin/master) * d968810 - Add comment line 3 * dfd7dcd - Add comment line 2 * a671eb0 - Add comment line 1 * 4b19495 - Add index page ``` --- ## What is the commit hash ? ```bash git cat-file commit faace497d0644e1c0f5f08e7f9753b19f4227172 ``` ``` tree 5e1bb24d501fc601cf429c9d963d0cdcf709521a parent d968810e0e2b3e1a77af1ffb53bcaf14457bdc64 author mRoca <mroca.dh@gmail.com> 1460712656 +0200 committer mRoca <mroca.dh@gmail.com> 1460712656 +0200 Add comment line 4 ``` The commit hash function : ``` sha1( commit message => "Add comment line 4" commiter => Michel Roca <mroca.dh@gmail.com> commit date => Fri Apr 15 11:30:56 2016 +0200 author => Michel Roca <mroca.dh@gmail.com> author date => Fri Apr 15 11:30:56 2016 +0200 tree => 5e1bb24d501fc601cf429c9d963d0cdcf709521a parents => [d968810e0e2b3e1a77af1ffb53bcaf14457bdc64] ) ``` --- ## A new feature must be developed **Create a new branch** ```bash git checkout -b feature/add-cool-subtitle master ``` **Code** ``` <h1>My lovely website</h1> +<h2>A cool subtitle</h3> + <script type="application/javascript" src="script.js"></script> ``` **Commit** ```bash git commit -am "Add a cool subtitle" ``` ``` * 92537a3 - Add a cool subtitle (feature/add-cool-subtitle) * faace49 - Add comment line 4 (origin/master) * d968810 - Add comment line 3 * dfd7dcd - Add comment line 2 * a671eb0 - Add comment line 1 * 4b19495 - Add index page ``` --- ## ... And we add more and more code **Fix things, add things, code things** ``` <h1>My lovely website</h1> -<h2>A cool subtitle</h3> +<h2>A cool subtitle, nop ?</h3> <script type="application/javascript" src="script.js"></script> ``` **Commit & Push** ```bash git commit -am "Fix the cool subtitle" git push -u origin feature/add-cool-subtitle ``` ``` * 6bac0fd - Fix the cool subtitle (origin/feature/add-cool-subtitle) * 92537a3 - Add a cool subtitle * faace49 - Add comment line 4 (origin/master) * d968810 - Add comment line 3 * dfd7dcd - Add comment line 2 * a671eb0 - Add comment line 1 * 4b19495 - Add index page ``` --- ## The branch is ok, we create the PR  --- ## The PR is here ! ``` [RFR] Add cool subtitle ``` * [RFR] = Ready for review * [WIP] = Work in progress **Cool : it's [RFR], the reviewers can now approve the PR with a `+1`** > We can use tags or colors instead of prefixes --- ## ... but the PR is not ok : a reviewer writes some comments  --- ## The developper fixes the PR **Fix things, add things, code things** ``` -<h2>A cool subtitle</h3> +<h2>A cool subtitle, nop ?</h2> ``` **Commit & Push** ```bash git commit -am "Fix the title" git push ``` ``` * b4f62fe - Fix the title (origin/feature/add-cool-subtitle) * 6bac0fd - Fix the cool subtitle * 92537a3 - Add a cool subtitle * faace49 - Add comment line 4 (origin/master) * d968810 - Add comment line 3 * dfd7dcd - Add comment line 2 * a671eb0 - Add comment line 1 * 4b19495 - Add index page ``` > Tips : the `git commit --amend` command adds the current changes in the previous commit --- ## The PR is now ok The reviewer adds a +1 comment in the PR page, the developer can now merge his PR ! *But...* --- ## Other commits have been merged by other developers into master  ``` * eaa707b - Add the boss word (origin/feature/add-boss-word) | * b4f62fe - Fix the title (origin/feature/add-cool-subtitle) | * 6bac0fd - Fix the cool subtitle | * 92537a3 - Add a cool subtitle |/ * faace49 - Add comment line 4 (origin/master) * d968810 - Add comment line 3 * dfd7dcd - Add comment line 2 * a671eb0 - Add comment line 1 * 4b19495 - Add index page ``` --- ## Conflicts resolving - Option 1 : Merge ```bash git merge master ``` ``` <<<<<<< HEAD <h2>A cool subtitle, nop ?</h2> ======= <p>I love you ! <em>The boss.</em></p> >>>>>>> master ``` ```bash git commit -a ``` ``` Merge branch 'master' into feature/add-cool-subtitle Conflicts: index.html ``` ```bash git push ``` --- ## Conflicts resolving - Option 1 : Merge The branches states after merge : ``` * 5516331 - Merge branch 'master' into feature/add-cool-subtitle (origin/feature/add-cool-subtitle) |\ | * 44d94c9 - Merge PR #4 from feature/add-boss-word (origin/master) | |\ | | * eaa707b - Add the boss word | |/ * | b4f62fe - Fix the title * | 6bac0fd - Fix the cool subtitle * | 92537a3 - Add a cool subtitle |/ * faace49 - Add comment line 4 * d968810 - Add comment line 3 * dfd7dcd - Add comment line 2 * a671eb0 - Add comment line 1 * 4b19495 - Add index page ``` --- ## Conflicts resolving - Option 1 : Merge If the PR is now merged, another merge commit will be created : ``` * 829218c - Merge PR #3 from feature/add-cool-subtitle (origin/master) |\ | * 5516331 - Merge branch 'master' into feature/add-cool-subtitle | |\ | |/ |/| * | 44d94c9 - Merge PR #4 from feature/add-boss-word |\ \ | * | eaa707b - Add the boss word |/ / | * b4f62fe - Fix the title | * 6bac0fd - Fix the cool subtitle | * 92537a3 - Add a cool subtitle |/ * faace49 - Add comment line 4 * d968810 - Add comment line 3 * dfd7dcd - Add comment line 2 * a671eb0 - Add comment line 1 * 4b19495 - Add index page ``` * Problem 1 : There are useless commits * Problem 2 : The project history is ugly and not useful --- ## Conflicts resolving - Option 2 : Rebase The `git rebase` command allows to rewrite the branch history. ```bash git rebase master ``` Conflict with `Add a cool subtitle` : ``` <<<<<<< HEAD <p>I love you ! <em>The boss.</em></p> ======= <h2>A cool subtitle</h3> >>>>>>> Add a cool subtitle ``` ```bash git rebase --continue ``` ... The `rebase`will apply diff merge on **EACH** commit of the target branch to rewrite history ```bash git push -f ``` --- ## Conflicts resolving - Option 2 : Rebase Before : ``` * 44d94c9 - Merge PR #4 from feature/add-boss-word (origin/master) |\ | * eaa707b - Add the boss word |/ | * b4f62fe - Fix the title (origin/feature/add-cool-subtitle) | * 6bac0fd - Fix the cool subtitle | * 92537a3 - Add a cool subtitle |/ * faace49 - Add comment line 4 ... ``` After : ``` * 5d634d1 - Fix the title (origin/feature/add-cool-subtitle) * 139770d - Fix the cool subtitle * 4650798 - Add a cool subtitle * 44d94c9 - Merge PR #4 from feature/add-boss-word (origin/master) |\ | * eaa707b - Add the boss word |/ * faace49 - Add comment line 4 ... ``` --- ## Git rebase Before : ``` * * * * * * (master) * * * * (feature) ``` After : ``` * * * * * * (master) * * * * (feature) ``` --- ## What about our commits ? The feature branch contains 3 commits for 1 updated line. This is not cool. The solution : we can "squash" the 3 commits onto 1 new commit ! --- ## Git squash ```bash git rebase -i HEAD~3 ``` ``` pick 4650798 Add a cool subtitle pick 139770d Fix the cool subtitle pick 5d634d1 Fix the title # Rebase 44d94c9..5d634d1 onto 44d94c9 # # Commands: # p, pick = use commit # r, reword = use commit, but edit the commit message # e, edit = use commit, but stop for amending # s, squash = use commit, but meld into previous commit # f, fixup = like "squash", but discard this commit's log message # x, exec = run command (the rest of the line) using shell ``` ``` pick 4650798 Add a cool subtitle squash 139770d Fix the cool subtitle s 5d634d1 Fix the title ``` --- ## Git squash After saving : ``` # This is a combination of 3 commits. # The first commit's message is: Add a cool subtitle # This is the 2nd commit message: Fix the cool subtitle # This is the 3rd commit message: Fix the title ``` ``` # This is a combination of 3 commits. # The first commit's message is: Add a cool subtitle # This is the 2nd commit message: # This is the 3rd commit message: ``` ``` [HEAD detached 65da5a8] Add a cool subtitle 1 file changed, 2 insertions(+) Successfully rebased and updated refs/heads/feature/add-cool-subtitle. ``` --- ## Git squash ```bash git push -f ``` ``` * 65da5a8 - Add a cool subtitle (origin/feature/add-cool-subtitle) * 44d94c9 - Merge PR #4 from feature/add-boss-word (origin/master) |\ | * eaa707b - Add the boss word |/ * faace49 - Add comment line 4 * d968810 - Add comment line 3 * dfd7dcd - Add comment line 2 * a671eb0 - Add comment line 1 * 4b19495 - Add index page ``` --- ## The PR is now approved and mergeable  --- ## The PR is now approved and mergeable  --- ## The PR is now approved and mergeable  --- ## The result : an atomic and unique commit, a clean history ``` * 0e3382f - Merge PR #5 from feature/add-cool-subtitle (origin/master) |\ | * 65da5a8 - Add a cool subtitle |/ * 44d94c9 - Merge PR #4 from feature/add-boss-word |\ | * eaa707b - Add the boss word |/ * faace49 - Add comment line 4 * d968810 - Add comment line 3 * dfd7dcd - Add comment line 2 * a671eb0 - Add comment line 1 * 4b19495 - Add index page ``` --- ## Development workflow * `git checkout -b feature/my-new-feature master` * Code.... * `git commit` * `git commit` * ... * `git rebase master` * `git push -u origin feature/my-new-feature` * PR creation * Review... * Code & fixes... * `git commit --amend && git push -f` * Review... +1 ! * Merge PR * GOTO begin ;-) --- ## Development workflow  https://www.atlassian.com/pt/git/workflows#!workflow-gitflow --- ## Naming convention | Item | Name | | --------------------- | ----------------------------- | | Release branch | release/v2.0.1 | | Feature branch | feature/my_feature_name | | Feature branch | feature/2234_my_feature_name | | Hotfix branch | hotfix/my_hotfix_name | | Commit | Add my news | | Tag | v2.0.1 | | Hotfix Tag | v2.0.1.1 | | Work in progress PR | [WIP] #1234 My pull request | | Ready for review PR | [RFR] #1234 My pull request | ​> When applied, this commit will: {{ Your commit message }} --- ## Cheat Sheet https://gist.github.com/mRoca/ecbe2b82d94c7ef440f8 ## Advanced git http://csarrazi-slides.github.io/git-for-teams/#/ --- ## Credits * Git workflow image : https://www.atlassian.com/pt/git/workflows#!workflow-gitflow