git

Transcript

1. Version Control System Ynon Perek Tuesday, March 6, 2012
2. Working On A Project !"" include # !"" entry.h # $"" user.h !"" lib !"" resources $"" src !"" entry.c !"" main.c $"" user.c !"" include # !"" entry.h # !"" photo.h # $"" user.h !"" lib !"" resources # $"" default.png $"" src !"" entry.c !"" main.c !"" photo.c $"" user.c Tuesday, March 6, 2012
3. Working On A Project • In a managed project, we have virtual “save points” of the entire file system • Think old “quest” games Tuesday, March 6, 2012
4. Reasons For VCS • Go back to a better previous state • Backup everything • Change is your friend • Collaboration Tuesday, March 6, 2012
5. Collaboration • Everyone knows what others are working on • Easily integrate other developer’s work Tuesday, March 6, 2012
6. Same File Collaboration Tuesday, March 6, 2012
7. Assume The Following int add(int x, int y) { return x + y; } int deleteFile(char *filename) { // delete a file } int add(int x, int y) { // adds x and y return x + y; } int deleteFile(char *filename) { } Bob Alice Tuesday, March 6, 2012
8. Merged Work int add(int x, int y) { // adds x and y return x + y; } int deleteFile(char *filename) { // delete a file } • Both developers’ work is in the file Tuesday, March 6, 2012
9. Centralized / Distributed All data is stored on the server All data is stored locally A client keeps a ‘workspace’, only a single state Each client keeps entire project history Server is required for every operation Server is only required for collaboration Tuesday, March 6, 2012
10. Available VCSs • Subversion, cvs, perforce, ClearCase, SourceSafe • Git, Mercurial, Bazaar • Let’s talk about git Tuesday, March 6, 2012
11. “Cool Kids” Version control system git Tuesday, March 6, 2012
12. git “Git -noun British Slang. an Unpleasant or contemptible person” -Oxford English Dictionary Tuesday, March 6, 2012
13. I’m an egotistical bastard, and I name all my projects after myself. First Linux, now git Tuesday, March 6, 2012
14. Working With Git • Set up a repository • Make changes and commit • Access and diff with past versions • Time Wraps (branching) • Collaboration Tuesday, March 6, 2012
15. Setting up the Repo • Create a new repository • All repository data is stored in .git folder cd myproject git init Tuesday, March 6, 2012
16. Project Changelist • A change list represents changes in a project from state A to state B • Changes include: • New files • Deleted (removed) files • Modified files Tuesday, March 6, 2012
17. Editing Changelist # Add main.c to the changelist git add main.c # Add all files in current directory to the changelist git add . # Add all .cpp files to the change list git add *.cpp # Insert a Remove File command to the change list git rm mistake.cpp # Insert a Rename command to the change list git mv persons.cpp people.cpp Tuesday, March 6, 2012
18. Editing Changelist # Add all .c files to the change list git add *.c # Remove main.c from the change list git reset main.c Tuesday, March 6, 2012
19. Committing A Changelist • Use git commit to save a changelist to the local repository • Use git reset --hard to restore last saved version Tuesday, March 6, 2012
20. Demo !"" include # !"" entry.h # $"" user.h !"" lib !"" resources $"" src !"" entry.c !"" main.c $"" user.c !"" include # !"" contact.h (previously was entry.h) # !"" photo.h (New) # $"" user.h !"" lib !"" resources # $"" default.png (New) $"" src !"" contact.c (previously was entry.c) !"" main.c !"" photo.c (New) $"" user.c Tuesday, March 6, 2012
21. Getting Status > git status # On branch master # Changes to be committed: # (use "git reset HEAD <file>..." to unstage) # #! renamed: include/entry.h -> include/contact.h #! renamed: src/entry.c -> src/contact.c # # Untracked files: # (use "git add <file>..." to include in what will be committed) # #! include/photo.h #! resources/ #! src/photo.c > git commit Tuesday, March 6, 2012
22. Getting Status > git log commit 6a0cf56dfbbd8334c28a8ee5b2f88ced42cb8fa2 Author: ynonp <ynonperek@gmail.com> Date: Thu Feb 16 07:46:18 2012 +0200 New Feature: User photos commit d70f574d2f6a3a67de69ee58a2e27daff4c6b10e Author: ynonp <ynonperek@gmail.com> Date: Thu Feb 16 07:40:56 2012 +0200 First commit Tuesday, March 6, 2012
23. Getting Status • Use git status to get current directory status • Use git log to list history • In the log, each entry has a commit number. Use git checkout d70f To go back a given commit number Tuesday, March 6, 2012
24. Checking Out • git checkout takes a commit number and temporarily restore state to that commit • Making changes to a past state will open a new branch • Use git checkout master to go back to head • Always commit or reset changes before checking out Tuesday, March 6, 2012
25. Past: In Depth • Use git diff d70f to diff with previous version (in this case d707) • Use git show d70f:main.c to show file main.c from commit d707 Tuesday, March 6, 2012
26. Q & A • Set up a repository • Make changes and commit • Access and diff with past versions • Time Wraps (branching) • Collaboration Tuesday, March 6, 2012
27. Branching • Context switching is inevitable • A friend needs your help for a version she’s working on • Working on a new feature, a new bug was found in a released version Tuesday, March 6, 2012
28. Branching Work (A) Work (B) Work (C) Work (B) Work (B’) Work (B’’) Work (D) Tuesday, March 6, 2012
29. Branching Commands • Use git branch feature to create a new branch named feature • Use git checkout feature to switch to the new branch • Use git checkout -b d70f to start a new branch from old commit • Use git branch for info Tuesday, March 6, 2012
30. Branching Flow # Working on the project, when suddenly a client calls. # She found a bug in release d70f # Commit all active work git commit -a # Create a new branch called fixes starting from commit d70f git checkout -b fixes d70f # Fix bug ... # Commit your newly fixed code git commit -a # Get back to work git checkout master Tuesday, March 6, 2012
31. Merging • Use git merge fixes to merge the branch named fixes into current branch • Use git branch -d fixes to delete the branch named fixes after you’re done with it Tuesday, March 6, 2012
32. Q & A Branches Tuesday, March 6, 2012
33. Gitting Together • A central repository is used to synchronize multiple developers • Each developer sees the repository as a remote branch • Commits can be pushed to the remote Tuesday, March 6, 2012
34. Gitting Together • Create an empty central repository • Fill it with some initial data • Have other devs clone the repository Tuesday, March 6, 2012