Leveling up your git skills

This talk is designed to help those who know a little bit about git and give them a bit of knowledge and some confidence to level up those skills.

Transcript

1. Becoming a Pro at Git Chris Keathley / @ChrisKeathley / c@keathley.io
2. I work with a distributed team
3. I work with a distributed team
6. “We don’t have the luxury of a focus room”
7. Everything is a- synchronous
8. submitPR() .then(waitForApproval) .then(mergePR) .then(startDeployFromSlack)
12. Image of green merge button
13. History is critical
16. $ git checkout c652b6b Note: checking out 'c652b6b'. You are in 'detached HEAD' state. You can look around, make experimental changes and commit them, and you can discard any commits you make in this state without impacting any branches by performing another checkout. If you want to create a new branch to retain commits you create, you may do so (now or later) by using -b with the checkout command again. Example: git checkout -b <new-branch-name> HEAD is now at c652b6b... Add kubernetes setup to fish shell.
17. You are in 'detached HEAD' state.
18. 'detached HEAD'
19. (Picture of a detached head)
20. $ hg merge --help --verbose | wc -w # => 327
21. $ hg merge --help --verbose | wc -w # => 327 $ git merge --help | wc -w # => 3958
23. Lets talk about… The golden rule of git Tools Scenarios
24. Git’s Golden Rule
26. If you don’t panic you can fix 100% of problems
27. Tooling
28. Git
29. Git No, Seriously
33. You Git CLI
34. CliTools
35. Aliases
36. alias g='git' alias gaa='git add -A' alias gb='git branch' alias gc='git commit' alias gco='git checkout' alias gd='git diff' alias gglr='git pull --rebase' alias ggp='git push' alias gst='git status'
37. alias wip='git add -A && git commit -m "WIP"' alias gc!='git commit -v --amend' alias ggp!='git push --force'
38. alias ibase='git rebase -i $(git merge-base HEAD master)' alias gpr='git pull-request -o' alias gcm='git remote show origin \ | awk '/HEAD branch:/ {print \$3}' \ | xargs git checkout'
39. Diffs
40. diff-so-fancy
41. Diff-So-Fancy
42. diff-so-fancy
44. $ git checkout https://github.com/github/hub/pull/134 Checkout PR
45. Apply patch $ git am https://github.com/xoebus/hub/commit/177eeb8
46. $ git pull-request Submit PR from cli
47. Git Scripts
48. Git Scripts λ cat ~/.bin/git-guilt #!/bin/sh git commit --amend --author "$1 <$2>" -C HEAD
49. Git Scripts λ git guilt "Grace Hopper" "grace@hopper.com" You need a passphrase to unlock the secret key for user: "Chris Keathley <c@keathley.io>" 4096-bit RSA key, ID EA3A16BD, created 2017-04-23 [test-branch 0beb550] New file for demo Author: Grace Hopper <grace@hopper.com> Date: Wed May 3 21:54:10 2017 -0400 1 file changed, 0 insertions(+), 0 deletions(-) create mode 100644 new_file
50. Scenarios
52. Scenario: Your first Bug
54. Don’t Panic
55. Git Bisect
56. λ git bisect start HEAD HEAD~10
57. λ git bisect start HEAD HEAD~10 Start a new bisect
58. λ git bisect start HEAD HEAD~10 Start a new bisect The “bad” revision
59. λ git bisect start HEAD HEAD~10 Start a new bisect The “bad” revision The “Good” revision
60. λ git bisect start HEAD HEAD~10
61. λ git bisect start HEAD HEAD~10
62. λ git bisect good
63. λ git bisect good
64. λ git bisect good
65. λ git bisect bad
66. λ git bisect bad
67. λ git bisect bad
68. λ git bisect bad
69. λ git bisect bad 6fb10e5ec916063e4b4bd744678559afb45d6791 is the first bad commit commit 6fb10e5ec916063e4b4bd744678559afb45d6791 Author: Aaron Renner <aaron.renner@gmail.com> Date: Tue May 2 07:55:01 2017 -0600 Fix leaking webdriver sessions in QueryTest (#209) Wallaby.Integration.QueryTest was starting a ton of sessions and not cleaning them up. This switches it over to use Wallaby.Integration.SessionCase and uses the session that's automatically created and cleaned up. I also extracted the unit tests out of this integration test so they can be run separately.
70. 6fb10e5ec916063e4b4bd744678559afb45d6791
71. λ git show -p 6fb10e5ec916063e4b4bd744678559afb45d6791
72. You just found the code that introduced the bug!
73. (Picture of Wizard)
74. $ cat test_script.sh #!/bin/bash if tests_pass; then exit 1; else exit 0; fi
75. $ git bisect run test_script.sh
77. A Brief interlude to discuss the value of Commit history
78. Bisect only works if the repo history is clean
79. wip merge Repo History wip
80. If you history looks like this its almost impossible to use bisects effectively
81. Make commits small atomic units of awesome!
82. Scenario: Start a feature
84. Lets talk about branching
85. Some of y’all have some crazy-ass branching strats
86. Development Production
88. Master Branch How we merge our code
89. $ git checkout master $ git pull --rebase $ git checkout -b feature/my-fancy-form-123456
90. feature/my-fancy-form-123456
91. feature/ chores/ bug/
93. When suddenly…
95. Don’t Panic
96. $ git add -A && git commit -m "WIP" $ git push -u origin HEAD Wip && Push
97. Now your work is saved and shared
98. $ git checkout master $ git checkout -b bugs/put-out-server-fire
101. Picture of blank stare
102. What happened?
103. $ git checkout master $ git checkout -b bugs/put-out-server-fire
104. $ git checkout master $ git pull —rebase $ git checkout -b bugs/put-out-server-fire
105. Master
106. Master
107. Master
108. Master
109. Master Conflict between files
110. Don’t Panic
111. $ git rebase master
112. $ git rebase master
113. $ git rebase master
114. Scenario: Fixing history
115. $ git checkout master $ git pull --rebase $ git checkout - $ git rebase master
116. $ git checkout master $ git pull --rebase $ git checkout - $ git rebase master
117. $ git checkout master $ git pull --rebase $ git checkout - $ git rebase master
118. $ git checkout master $ git pull --rebase $ git checkout - $ git rebase master
119. λ git rebase master First, rewinding head to replay your work on top of it... Applying: My Fancy Fix Using index info to reconstruct a base tree... M README.md Falling back to patching base and 3-way merge... Auto-merging README.md CONFLICT (content): Merge conflict in README.md error: Failed to merge in the changes. Patch failed at 0001 WIP The copy of the patch that failed is found in: .git/rebase-apply/patch When you have resolved this problem, run "git rebase --continue". If you prefer to skip this patch, run "git rebase --skip" instead. To check out the original branch and stop rebasing, run "git rebase --abort".
120. Resolve Conflicts
121. Resolve Conflicts $ git add -A $ git rebase —continue
122. Resolve Conflicts $ git push —force
124. Scenario: Finishing our feature
126. Picture of coffee
127. $ git checkout feature/my-fancy-feature Checkout the feature branch
129. WIP commit New Stuff
130. WIP commit New Stuff
131. WIP commit New Stuff other stuff
132. Interactive Stage
145. $ git commit Commit the current changes
146. $ git add -A $ git commit Commit everything else
147. $ git add -A $ git commit Commit everything else
148. WIP commit New Stuff other stuff
149. other stuff New Stuff
150. Interactive Rebase
151. $ git rebase -i HEAD~3 Interactive Rebase
157. other stuff New Stuff
158. Scenario: Loosing a commit
160. $ git rebase -i HEAD~10
161. λ git rebase master First, rewinding head to replay your work on top of it... Applying: My Fancy Fix Using index info to reconstruct a base tree... M README.md Falling back to patching base and 3-way merge... Auto-merging README.md CONFLICT (content): Merge conflict in README.md error: Failed to merge in the changes. Patch failed at 0001 WIP The copy of the patch that failed is found in: .git/rebase-apply/patch When you have resolved this problem, run "git rebase --continue". If you prefer to skip this patch, run "git rebase --skip" instead. To check out the original branch and stop rebasing, run "git rebase --abort".
162. $ git rebase --continue
163. λ mix test 1) test it works (Metaform.Web.PageViewTest) test/web/views/page_view_test.exs:4 This is broken now stacktrace: test/web/views/page_view_test.exs:5: (test) .... Finished in 0.1 seconds 5 tests, 1 failure
165. Picture of you crying
166. Your work was lost in a conflict
167. Don’t Panic
168. $ git reflog
169. The reflog is all of your repos history
170. $ git reflog
171. f1b1 HEAD@{0}: rebase -i (finish): returning to refs/heads/chores/remove-select 677f1b1 HEAD@{1}: rebase -i (pick): Update new file f55b0d8 HEAD@{2}: cherry-pick: fast-forward f4b7d8b HEAD@{3}: rebase -i (start): checkout HEAD~3 ca47093 HEAD@{4}: commit: Update new file 039d19a HEAD@{5}: commit (amend): My super important commit don't loose this. 62fc606 HEAD@{6}: rebase -i (finish): returning to refs/heads/chores/remove-select
172. f1b1 HEAD@{0}: rebase -i (finish): returning to refs/heads/chores/remove-select 677f1b1 HEAD@{1}: rebase -i (pick): Update new file f55b0d8 HEAD@{2}: cherry-pick: fast-forward f4b7d8b HEAD@{3}: rebase -i (start): checkout HEAD~3 ca47093 HEAD@{4}: commit: Update new file 039d19a HEAD@{5}: commit (amend): My super important commit don't loose this. 62fc606 HEAD@{6}: rebase -i (finish): returning to refs/heads/chores/remove-select
173. 039d19a
174. $ git show -p 039d19a $ git reset —hard 039d19a
176. Conclusion
177. Resources Diff-so-fancy - https://github.com/so-fancy/diff-so-fancy Hub - https://github.com/github/hub Slides - https://speakerdeck.com/keathley
178. CLI
179. Tools
180. Branching
181. Rebase
182. Reflog
183. Don’t Panic
184. Thanks! Chris Keathley @ChrisKeathley c@keathley.io