Using GIT

Disclaimer

Glossary

History graph

Tag

Branch

After commit

Detached HEAD

Detached HEAD after commit

Common operations

Examine the history

• git log
• git log --graph
• git log -G
• git show

Referencing a commit

• dae86e1950b1277e545cee180551750029cfe735
• HEAD, @
• tag name, branch name
• @{u}, branch@{u}
• foo^ (HEAD^, dae86e^, tag^, @{u}^, ...)
• foo~2, foo~3, foo~10, ...
• :/regex, foo^{/regex}

HEAD^^3~2^2

Ranges

• rev
• rev1..rev2
• rev1...rev2

• ^rev
• rev^@
• rev^!

red..blue

red..green

red...green

git gui

• git gui blame
• git gui citool

• gitk

gitk

• compact graph, easy navigation
• search (comments and diffs!)
• non-blocking!
• gitk branch, gitk rev1..rev2
• gitk file
  

merge

git merge blue

fast-forward

git merge blue

rebase

git rebase blue

fetch

  $ git branch -a
* 10.1
  bb-10.1-monty
  bb-10.1-rediscover
  bb-10.1-serg
  galera-review
  remotes/origin/10.1
  remotes/origin/10.1-explain-json
  remotes/origin/bb-10.1-4ksectors
  remotes/origin/bb-10.1-serg
  remotes/origin/bb-fast-connect
  remotes/origin/bb-set-statement
  remotes/gsoc/selfTuningOptimizer
  remotes/roles/10.1

pull

• fetch + merge
• git pull --rebase
• git pull --ff-only
• git config pull.ff only
• gitk remotes/origin/10.1...10.1
  
• gitk @{u}...

pull/push --overwrite

• bzr push --overwrite
  • git push --force
• bzr pull --overwrite
  • git pull --force
  • ???

mergetool

• for each unmerged file
  • ask what to do (use this or that, edit, etc)
  • run a merge tool
  • mark the file as “merged”

Move changes to a new branch

clean history

• linear history: pull.ff=only, rebase
• separate changes: git add -p
• history cleanup: interactive rebase

git rebase --interactive HEAD~5

pick a1e3eaf fix a duplicate macro definition
pick de4cfab sort a non-deterministic test result
pick b4daf8e split an assert
pick 90f2ec5 bugfix: incorrect cast causing random memory write
pick ab440b0 update sysvars_server_embedded,32bit.rdiff

# Rebase fe0112e..ab440b0 onto fe0112e
#
# 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

Keep a backup

• simply create a new branch at your current HEAD
• git branch backup

Keep a backup

bisect

$ git bisect start
$ git bisect bad
$ git bisect good HEAD~12
Bisecting: 5 revisions left to test (roughly 3 steps)
[fe0112e2] MDEV-7424: InnoDB: Assertion failure in thread 139901753345792   in file buf0mtflu.cc line 439
$ make; cd mysql-test; ./mtr sometest
$ git bisect good
Bisecting: 2 revisions left to test (roughly 2 steps)
[de4cfabe] sort a non-deterministic test result
$ 

automating bisect

$ git bisect start
$ git bisect bad
$ git bisect good HEAD~12
Bisecting: 5 revisions left to test (roughly 3 steps)
[fe0112e2] MDEV-7424: InnoDB: Assertion failure in thread 139901753345792   in file buf0mtflu.cc line 439
$ git bisect run make-and-run-mtr --noreorder foo bar

$ cat make-and-run-mtr
#!/bin/sh -ex
make -j5 || exit 125
cd mysql-test && ./mtr "$@"

Multiple repositories
bzr style