Dev conf git_lecture

git internals

Juan de Bravo

@juandebravo

git internals DevCon I 2012/11/27


Git. Definition Page 2

free and open source distributed version control system designed to handle everything from small to very large projects with speed and efficiency


Git. Distributed repository Page 3

git "usual commands"

git workflow

this talk is not about…

github/pdihub


Disclaimer Page 4

this talk is about…


Disclaimer 2 Page 5

1

2

git internals

git advanced topics

3 git tips & tricks


1

2

git internals

git advanced topics

3 git tips & tricks



1 git internals

git objects1.1

1.2 git internal structure


1 git internals

git objects1.1



1.1 git objects. types Page 10

- blobs : content- trees : content structure- commits: history snapshots- tags : named commits/objects

git defines 4 object types


1.1 git objects. storage Page 11

These objects are stored individually inside the .git/objects folder

λ find .git/objects | wc -l 628




1.1 git objects. format and filename Page 12

git object filenameSHA1 of the previous format applied to the object

- object type: blob|tree|commit|tag- content size- null byte- content

git object format


1 git internals

git objects1.1

1.1.1 git blob


1.1.1 git objects. blobs Page 14

Git stores every single file content using a blob object with the git format (object type, etc)

<Blob SHA1>


1.1.1 git objects. blobs 3 Page 15

git hash-object


1.1.1 git objects. blobs 2 Page 16

$ echo 'Hello, world!' > foo$ git hash-object fooaf5626b4a114abcb82d63db7c8082c3c4756e51b

$ git hash-object --stdinHello, world!^Daf5626b4a114abcb82d63db7c8082c3c4756e51b

$ echo -en 'blob 14\0Hello, world!\n' | shasumaf5626b4a114abcb82d63db7c8082c3c4756e51b

Git stores every single file using a blob object with the predefined format.


1.1.1 git objects. blobs. stdin Page 17

$ git init$ find .git/objects .git/objects .git/objects/info .git/objects/pack

$ echo 'Hello, world!' | git hash-object -w --stdin$ find .git/objects .git/objects .git/objects/af .git/objects/af/5626b4a114abcb82d63db7c8082c3c4756e51b .git/objects/info .git/objects/pack


1.1.1 git objects. blobs. file Page 18

$ git init$ find .git/objects .git/objects .git/objects/info .git/objects/pack

$ echo 'Hello, world!' > foo$ git add foo$ find .git/objects .git/objects .git/objects/af .git/objects/af/5626b4a114abcb82d63db7c8082c3c4756e51b .git/objects/info .git/objects/pack


1.1.1 git objects. blobs. cat-file 1 Page 19

git cat-file


1.1.1 git objects. blobs. cat-file Page 20

$ git cat-file -t af5626b4a114abcb82d63db7c8082c3c4756e51b blob

$ git cat-file -s af5626b4a114abcb82d63db7c8082c3c4756e51b 14

$ git cat-file -p af5626b4a114abcb82d63db7c8082c3c4756e51b Hello, world!

$ git cat-file blob af5626b4a114abcb82d63db7c8082c3c4756e51b Hello, world!


1.1.1 git objects. blobs. no file info Page 21

$ # porcelain$ echo 'Hello, world!' > foo$ git add foo

$ # plumbing$ echo 'Hello, world!' | git hash-object -w --stdin

The following two commands are similar

In both cases, a blob object is created in .git/objects

.git/objects/af/5626b4a114abcb82d63db7c8082c3c4756e51b


1.1.1 git objects. blobs. blob content Page 22

af

fooHello, world!

5626b4a114abcb82d63db7c8082c3c4756e51b

.git/objects/af/5626b4a114abcb82d63db7c8082c3c4756e51b

.foo

blob 14\0Hello, world!\n

af5626b


1 git internals

git objects1.1

1.1.2 git trees


1.1.2 git objects. trees Page 24

Trees are used to: - store the filename of a specific file - store a group of files together

<Tree SHA1>


1.1.2 git objects. trees 2 Page 25

# Add a file content to git $ echo 'Hello, world!' > foo$ git add foo$ find .git/objects .git/objects .git/objects/af .git/objects/af/5626b4a114abcb82d63db7c8082c3c4756e51b .git/objects/info .git/objects/pack


1.1.2 git objects. create a tree Page 26

# Add a file content to git $ mkdir bar$ echo 'Hello, world!' > bar/foo$ git add bar/foo$ find .git/objects .git/objects .git/objects/af .git/objects/af/5626b4a114abcb82d63db7c8082c3c4756e51b .git/objects/info .git/objects/pack


1.1.2 git objects. create a tree 2 Page 27

$ git commit -m 'first commit' [master (root-commit) 83862bb] first commit 2 files changed, 2 insertions(+), 0 deletions(-) create mode 100644 bar/foo create mode 100644 foo



$ find .git/objects .git/objects .git/objects/83 .git/objects/83/862bbb8472f0b802be96b5e59993ca044f3c31 .git/objects/a8 .git/objects/a8/54cc8b798fb00ad0c3a7a63508b8cffe2e979b .git/objects/af .git/objects/af/5626b4a114abcb82d63db7c8082c3c4756e51b .git/objects/f2 .git/objects/f2/df5266567842bbb8a06acca56bcabf813cd73f .git/objects/info .git/objects/pack



$ git cat-file -t 83862bbb8472f0b802be96b5e59993ca044f3c31 commit

$ git cat-file -t a854cc8b798fb00ad0c3a7a63508b8cffe2e979b tree

$ git cat-file -t af5626b4a114abcb82d63db7c8082c3c4756e51b blob

$ git cat-file -t f2df5266567842bbb8a06acca56bcabf813cd73f tree



git ls-tree


1.1.2 git objects. inspect a tree Page 31

$ git ls-tree a854cc8b798fb00ad0c3a7a63508b8cffe2e979b 040000 tree f2df5266567842bbb8a06acca56bcabf813cd73f bar 100644 blob af5626b4a114abcb82d63db7c8082c3c4756e51b foo

$ git ls-tree f2df5266567842bbb8a06acca56bcabf813cd73f 100644 blob af5626b4a114abcb82d63db7c8082c3c4756e51b foo

a854cc

f2df52

af5626

af5626


1.1.2 git objects. inspect a tree 2 Page 32

- Blobs does not store any file specific info

- File specific info is stored in trees

- Same operations, run in different computers, will create the same blobs/trees.


1.1.2 git objects. tree. plumbing Page 33

git update-indexgit write-tree


1.1.2 git objects. tree. plumbing 3 Page 34

A commit is the easiest way to create a tree, but it can be created manually (plumbing)

$ git update-index --add --cacheinfo 100644 \af5626b4a114abcb82d63db7c8082c3c4756e51b \bazz

$ git update-index --add --cacheinfo 100644 \af5626b4a114abcb82d63db7c8082c3c4756e51b \bazz2

$ git write-tree0a5de923df76ac94a71800e28a4e449171073e3e


1.1.2 git objects. tree. plumbing 2 Page 35

$ find .git/objects0a/5de923df76ac94a71800e28a4e449171073e3eaf/5626b4a114abcb82d63db7c8082c3c4756e51b

$ git ls-tree 0a5de923df76ac94a71800e28a4e449171073e3e

100644 blob af5626b4a114abcb82d63db7c8082c3c4756e51b bazz100644 blob af5626b4a114abcb82d63db7c8082c3c4756e51b bazz2

0a5de9

af5626

af5626


1 git internals

git objects1.1

1.1.3 git commit


1.1.3 git objects. commits Page 37

Create a snapshot of the current status of the repository

<Commit-SHA1>


1.1.3 git objects. commits 2 Page 38

$ git commit -m 'first commit' [master (root-commit) 83862bb] first commit 2 files changed, 2 insertions(+), 0 deletions(-) create mode 100644 bar/foo create mode 100644 foo

$ find .git/objects .git/objects .git/objects/83 .git/objects/83/862bbb8472f0b802be96b5e59993ca044f3c31 .git/objects/a8 .git/objects/a8/54cc8b798fb00ad0c3a7a63508b8cffe2e979b .git/objects/af .git/objects/af/5626b4a114abcb82d63db7c8082c3c4756e51b .git/objects/f2 .git/objects/f2/df5266567842bbb8a06acca56bcabf813cd73f .git/objects/info .git/objects/pack



$ git cat-file -p 83862bb tree a854cc8b798fb00ad0c3a7a63508b8cffe2e979b author juandebravo <[email protected]> 1353253703 +0100 committer juandebravo <[email protected]> 1353253703 +0100

first commit

$ git ls-tree HEAD$ git cat-file -p a854cc8b$ git cat-file -p "master^{tree}"

040000 tree f2df5266567842bbb8a06acca56bcabf813cd73f bar 100644 blob af5626b4a114abcb82d63db7c8082c3c4756e51b foo



83862bb af5626b

af5626b

a854cc8

f2df526


1 git internals

git objects1.1

1.1.4 git tag


1.1.4 git objects. tags. lightweight tag Page 42

lightweight tag

Similar to a commit, but points to a commit rather than to a tree

Like a branch reference, but it never moves


1.1.4 git objects. tags. lightweight tag 1 Page 43

λ git tag v1.0

λ git cat-file -p v1.0tree dba14fbffe61ae959c139d847fcf7709ac7f03d5parent 83862bbb8472f0b802be96b5e59993ca044f3c31author juandebravo <[email protected]> 1353954525 +0100committer juandebravo <[email protected]> 1353954525 +0100


1.1.4 git objects. tags. annotated tag Page 44

annotated tag

Stored as full objects:- checksum- tagger name, email, date- comment- can be signed and verified


1.1.4 git objects. tags. anotated tag Page 45

λ git tag -a v1.1 -m "version 1.1"

λ git cat-file -p v1.1object c2120756cce9f359373d2fd42f8eac5cd5f9cbe9type committag v1.1tagger juandebravo <[email protected]> Tue Nov 22 17:42:02 2012 +0100

version 1.1


1.1.4 git objects. tags. anotated tag 2 Page 46

λ cd CONNECT/tid-commonsλ ls -ltotal 32-rw-r--r-- 1 jdbd staff 1594 27 Nov 07:47 LICENSE.txt-rw-r--r-- 1 jdbd staff 1909 27 Nov 07:47 README.mddrwxr-xr-x 2 jdbd staff 68 22 Aug 13:21 dist-rw-r--r-- 1 jdbd staff 114 30 Oct 23:53 setup.cfg-rw-r--r-- 1 jdbd staff 312 27 Nov 07:47 setup.pydrwxr-xr-x 18 jdbd staff 612 27 Nov 07:47 testsdrwxr-xr-x 24 jdbd staff 816 27 Nov 07:47 tid_commons



λ git ls-tree HEAD100644 blob 0d20b6487c61e7d1bde93acf4a14b7a89083a16d .gitignore100644 blob a27144556d3b857a6fb609f39be204996e1f7792 LICENSE.txt100644 blob 15446c94618f3863584814d669048dc3def789cf README.md100644 blob b6c8d6c27ce614109dcb07b2e655ce13727675fa setup.cfg100644 blob 6ee4913e18e4a6a2320ac1e540a585f12bc110b2 setup.py040000 tree a7c28bc15f440bcf3783915f24ff3336b81dd01f tests040000 tree 35ea155eb6899a337b1b0ed5307d0882a0b7858e tid_commons



λ git tag -a LICENSE a2714455 -m "License file"

λ git cat-file -p LICENSEobject a27144556d3b857a6fb609f39be204996e1f7792type blobtag LICENSEtagger juandebravo <[email protected]> Tue Nov 27 07:48:36 2012 +0100

License file


1 git internals

git objects1.1



1.2 git internal structure Page 50

.git!"" COMMIT_EDITMSG!"" HEAD!"" branches!"" config!"" description!"" hooks!"" index!"" info#!! $"" exclude!"" logs#!! !"" HEAD#!! $"" refs#!! $"" heads#!! $"" master

!"" objects#!! !"" 83#!! #!! $"" 862bbb8472f0b802be96b5e59993ca044f3c31#!! !"" a8#!! #!! $"" 54cc8b798fb00ad0c3a7a63508b8cffe2e979b#!! !"" af#!! #!! $"" 5626b4a114abcb82d63db7c8082c3c4756e51b#!! !"" f2#!! #!! $"" df5266567842bbb8a06acca56bcabf813cd73f#!! !"" info#!! $"" pack$"" refs !"" heads #!! $"" master $"" tags


1.2.1 git internal structure. HEAD 1 Page 51

HEAD

reference to current checkout commit



$ cat .git/HEAD

ref: refs/heads/master

$ git status

# On branch masternothing to commit (working directory clean)



$ git checkout feature/memoize_client$ cat .git/HEAD

ref: refs/heads/feature/memoize/client

$ git branch feature/memoize_client$ cat .git/HEAD

ref: refs/heads/master



# Modify HEAD$ git symbolic-ref HEAD refs/head/master$ cat .git/HEAD

refs/heads/master

# Check where HEAD is pointing to$ git symbolic-ref HEAD

refs/heads/feature/memoize/client



# Example. zsh# get the name of the branch we are onfunction git_prompt_info() { ref=$(git symbolic-ref HEAD 2> /dev/null) || return echo "$ZSH_THEME_GIT_PROMPT_PREFIX${ref#refs/heads/}$(parse_git_dirty)$ZSH_THEME_GIT_PROMPT_SUFFIX"}

juandebravo [~/projects/git_internals/repo] (master) ✓


1.2.2 git internal structure. config Page 56

CONFIGrepository specific configuration


1.2.2 git internal structure. config 2 Page 57

λ cat .git/config [core]repositoryformatversion = 0filemode = truebare = falselogallrefupdates = trueignorecase = true


1.2.2 git internal structure. REFS Page 58

REFSreference to tags and branches commits


1.2.2 git internal structure. REFS 2 Page 59

!"" objects#!! !"" 83#!! #!! $"" 862bbb8472f0b802be96b5e59993ca044f3c31#!! !"" a8#!! #!! $"" 54cc8b798fb00ad0c3a7a63508b8cffe2e979b#!! !"" af#!! #!! $"" 5626b4a114abcb82d63db7c8082c3c4756e51b#!! !"" f2#!! #!! $"" df5266567842bbb8a06acca56bcabf813cd73f#!! !"" info#!! $"" pack$"" refs !"" heads #!! $"" feature #!! #!! $"" memoize_client #!! $"" master $"" tags



λ find .git/refs .git/refs.git/refs/heads.git/refs/heads/feature.git/refs/heads/feature/memoize_client.git/refs/heads/master.git/refs/tags



λ cat .git/refs/heads/feature/memoize_client

λ cat .git/refs/heads/master

83862bbb8472f0b802be96b5e59993ca044f3c31

83862bbb8472f0b802be96b5e59993ca044f3c31

λ git cat-file -p 83862bbb8472f0b802be96b5e59993ca044f3c31 tree a854cc8b798fb00ad0c3a7a63508b8cffe2e979bauthor juandebravo <[email protected]> 1353253703 +0100committer juandebravo <[email protected]> 1353253703 +0100

first commit



λ git checkout feature/memoize_clientλ echo "¿Cómo están ustedes?" >> foo

λ git commit -am "miliki, we love you"

[feature/memoize_client 7d52f00] miliki, we love you 1 files changed, 2 insertions(+), 0 deletions(-)



λ cat .git/refs/heads/feature/memoize_client

7d52f0083ebf11fdfd4ea00f6806e29fd8089ab2

λ cat .git/refs/heads/master

83862bbb8472f0b802be96b5e59993ca044f3c31



λ git log

7d52f00 - (HEAD, feature/memoize_client) miliki, we love you - juandebravo (15 minutes ago)

83862bb - (master) first commit - juandebravo (8 days ago)



λ git log

7d52f00 - (HEAD, feature/memoize_client) miliki, we love you - juandebravo (15 minutes ago)


λ git tag v1.07d52f00 - (HEAD, v1.0, feature/memoize_client) miliki, we love you - juandebravo (15 minutes ago)




λ find .git/refs .git/refs.git/refs/heads.git/refs/heads/feature.git/refs/heads/feature/memoize_client.git/refs/heads/master.git/refs/tags.git/refs/tags/v1.0



λ echo "Bieeeeeeeeen" >> foo

λ git commit -am "yet another commit"

[feature/memoize_client c212075] yet another commit 1 files changed, 1 insertions(+), 0 deletions(-)

λ cat .git/refs/tags/v1.0

7d52f0083ebf11fdfd4ea00f6806e29fd8089ab2



λ git log

c212075 - (HEAD, feature/memoize_client) yet another commit - juandebravo (87 seconds ago)7d52f00 - (v1.0) miliki, we love you - juandebravo (25 minutes ago)83862bb - (master) first commit - juandebravo (8 days ago)

1

2

git internals

git advanced topics

3 git tips & tricks


2 git advanced topics

git bisect2.1

2.2 git reflog

2.3 git stash



git bisect2.1

2.2 git reflog

2.3 git stash


The bisect command does a binary search through your commit history to help you identify as quickly as possible which commit introduced an issue.


2.1 git bisect Page 72


2.1 git bisect 17 Page 73

λ tree.!"" main#!! !"" __init__.py#!! $"" foo.py$"" tests $"" foo_tests.py



import re

reg_expr = re.compile('^\d{,10}$')

class Foo(object):

@staticmethod def is_valid(value): _value = reg_expr.match(str(value)) return True if _value else False



import unittestfrom pyshould import should

from main.foo import Foo

class TestFoo(unittest.TestCase):

def setUp(self): self.foo = Foo

def test_is_valid_string(self): self.foo.is_valid('1234') | should.be_true

def test_is_valid_number(self): self.foo.is_valid(1234) | should.be_true

def test_is_valid_one_digit(self): self.foo.is_valid(1) | should.be_true



λ nosetests -sv test_is_valid_number (foo_tests.TestFoo) ... oktest_is_valid_one_digit (foo_tests.TestFoo) ... oktest_is_valid_string (foo_tests.TestFoo) ... ok

---------------------------------------------------------Ran 3 tests in 0.013s

OK



λ git lg* 2ca0083 - (HEAD, master) change regepx - juandebravo (12 minutes ago)* 1824e4f - change regepx - juandebravo (12 minutes ago)* 898489c - change regepx - juandebravo (12 minutes ago)* f683803 - change regepx - juandebravo (12 minutes ago)* dbe4c2e - change regepx - juandebravo (12 minutes ago)* ec56109 - change regepx - juandebravo (12 minutes ago)* 14b0d5f - change regepx - juandebravo (13 minutes ago)* 938a43b - change regepx - juandebravo (13 minutes ago)* bb9f17a - change regepx - juandebravo (13 minutes ago)* a8aa38f - change regepx - juandebravo (13 minutes ago)* 74e307f - remove pyc files - juandebravo (2 hours ago)* 82e49f3 - fix .gitignore - juandebravo (2 hours ago)* 9a8bdf8 - first commit - juandebravo (2 hours ago)



λ nosetests -sv test_is_valid_number (foo_tests.TestFoo) ... FAILtest_is_valid_one_digit (foo_tests.TestFoo) ... oktest_is_valid_string (foo_tests.TestFoo) ... FAIL

-------------------------------------------------------Ran 3 tests in 0.013s

FAILED (failures=2)



1) Figure out a commit that was right: good commit2) Figure out a commit that is wrong: the current one, bad commit3) run git bisect command

git bisect is your friend



λ git lg* dc46efc - (HEAD, master) add unittest main - juandebravo (4 minutes ago)* 2ca0083 - change regepx - juandebravo (12 minutes ago)* 1824e4f - change regepx - juandebravo (12 minutes ago)* 898489c - change regepx - juandebravo (12 minutes ago)* f683803 - change regepx - juandebravo (12 minutes ago)* dbe4c2e - change regepx - juandebravo (12 minutes ago)* ec56109 - change regepx - juandebravo (12 minutes ago)* 14b0d5f - change regepx - juandebravo (13 minutes ago)* 938a43b - change regepx - juandebravo (13 minutes ago)* bb9f17a - change regepx - juandebravo (13 minutes ago)* a8aa38f - change regepx - juandebravo (13 minutes ago)* 74e307f - remove pyc files - juandebravo (2 hours ago)* 82e49f3 - fix .gitignore - juandebravo (2 hours ago)* 9a8bdf8 - first commit - juandebravo (2 hours ago)



reg = r'^\s*(?=^.{7,}$)(?=.*[a-zA-Z])(?=.*\d)(?!.*\s).*?\s*$'

reg_expr = re.compile(reg)



λ git bisect start HEAD 9a8bdf8

Bisecting: 5 revisions left to test after this (roughly 3 steps)[ec56109cc441293571a0773c83006afe483ff0e6] change regepx






$ git bisect run nosetests -sv

Ran 3 tests in 0.014s

OKBisecting: 2 revisions left to test after this (roughly 2 steps)[898489c1e7b77989717a84f08f49f43cf215c120] change regepx






----------------------------------------------------------Ran 3 tests in 0.014s

FAILED (failures=2)Bisecting: 0 revisions left to test after this (roughly 1 step)[f6838032010b18a7e3998f4a2fdcde65124424a2] change regepx






----------------------------------------------------------Ran 3 tests in 0.013s

OK898489c1e7b77989717a84f08f49f43cf215c120 is the first bad commitcommit 898489c1e7b77989717a84f08f49f43cf215c120Author: juandebravo <[email protected]>Date: Mon Nov 26 21:48:50 2012 +0100

change regepx

:040000 040000 70ccfdcf5d796cbd581a840c1c92ebe47b40345e 3912c8faed49a91e6fe3f68e7370a86c120c2844 M

mainbisect run success



λ git lg* dc46efc - (master) add unittest main - juandebravo (4 minutes ago)* 2ca0083 - change regepx - juandebravo (49 minutes ago)* 1824e4f - change regepx - juandebravo (49 minutes ago)* 898489c - (refs/bisect/bad) change regepx - juandebravo (49 minutes ago)* f683803 - (HEAD, refs/bisect/good-f6838032010b18a7e3998f4a2fdcde65124424a2) change regepx - juandebravo (49 minutes* dbe4c2e - change regepx - juandebravo (49 minutes ago)* ec56109 - (refs/bisect/good-ec56109cc441293571a0773c83006afe483ff0e6) change regepx - juandebravo (50 minutes ago)* 14b0d5f - change regepx - juandebravo (50 minutes ago)* 938a43b - change regepx - juandebravo (50 minutes ago)* bb9f17a - change regepx - juandebravo (50 minutes ago)* a8aa38f - change regepx - juandebravo (50 minutes ago)* 74e307f - (refs/bisect/good-74e307f9003e661f3c5e5f9697915d2a1de2e96e) remove pyc files - juandebravo (2 hours ago)* 82e49f3 - fix .gitignore - juandebravo (2 hours ago)* 9a8bdf8 - first commit - juandebravo (2 hours ago)



λ git bisect resetPrevious HEAD position was f683803... change regepxSwitched to branch 'master'

Reset: remove bisect information from history




git bisect2.1

2.2 git reflog

git stash

2.2

2.1

2.3

2.2


A log of where your HEAD and branch references have been for the last few months.


2.2 git reflog Page 93

It persists independently of other changes in your repository.

I could unlink any commit from my repository (using reset), yet it would still be referenced by the reflog for another 30 days!


2.2 git reflog 4 Page 94

dc46efc HEAD@{0}: checkout: moving from 2ca0083fc6ba6bdfbf3000122eba51359309ae7f to master2ca0083 HEAD@{1}: checkout: moving from master to HEAD@{22}dc46efc HEAD@{2}: checkout: moving from 1824e4fdcf1fc963554b2ae671ede799a692838a to master1824e4f HEAD@{3}: checkout: moving from ec56109cc441293571a0773c83006afe483ff0e6 to HEAD@{36}ec56109 HEAD@{4}: checkout: moving from master to HEAD@{70}dc46efc HEAD@{5}: checkout: moving from f6838032010b18a7e3998f4a2fdcde65124424a2 to masterf683803 HEAD@{6}: checkout: moving from 898489c1e7b77989717a84f08f49f43cf215c120 to f6838032010b18a7e3998f4a2fdcde651898489c HEAD@{7}: checkout: moving from ec56109cc441293571a0773c83006afe483ff0e6 to 898489c1e7b77989717a84f08f49f43cfec56109 HEAD@{8}: checkout: moving from master to ec56109cc441293571a0773c83006afe483ff0e6dc46efc HEAD@{9}: checkout: moving from master to masterdc46efc HEAD@{10}: checkout: moving from a8aa38f28e9bc76bdc73603b73f1a31a674b28dd to master

$ git reflog



$ git show HEAD@{5}

$ git show master@{2.months.ago}




git rebase2.1

2.2

git stash

2.2 git bisect

2.1

2.3


Imagine this scenario...


2.3 git stash 9 Page 98

1) you are working in a cool user story2) a JIRA task is assigned to you


2.3 git stash Page 99

1) you are working in a cool user story2) a JIRA task is assigned to you3) JIRA is down



1) you are working in a cool user story2) a JIRA task is assigned to you3) JIRA is down4) coffee while JIRA comes back to life5) you figure out what you should do6) you need to switch to another branch7) but you don't want to commit half-work





λ git status# On branch master# Changes not staged for commit:# (use "git add <file>..." to update what will be committed)# (use "git checkout -- <file>..." to discard changes in working directory)## modified: main/foo.py#no changes added to commit (use "git add" and/or "git commit -a")



λ git stashSaved working directory and index state WIP on master: dc46efc add unittest mainHEAD is now at dc46efc add unittest main

λ git stash liststash@{0}: WIP on master: dc46efc add unittest main



λ git lg* 7cf1d41 - (refs/stash) WIP on master: dc46efc add main - juandebravo (6 minutes ago)|\ | * 7bcc6de - index on master: dc46efc add unittest main - juandebravo (6 minutes ago)|/ * dc46efc - (HEAD, master) add unittest main - juandebravo (46 minutes ago)* 2ca0083 - change regepx - juandebravo (2 hours ago)* 1824e4f - change regepx - juandebravo (2 hours ago)* 898489c - change regepx - juandebravo (2 hours ago)



λ git cat-file commit 7cf1d41tree f1d28d6483820c19e43bc17d46f3a9ab393aba6fparent dc46efcfa8fee91b94ed40d78e8b43f7afc53196parent 7bcc6de1d49f8113d019e2c45b87938363bb54bdauthor juandebravo <[email protected]> 1353968043 +0100committer juandebravo <[email protected]> 1353968043 +0100

WIP on master: dc46efc add unittest main



λ git cat-file commit 7bcc6detree 71d53f971a4924e0cec9264a0774ba63a6eba3b9parent dc46efcfa8fee91b94ed40d78e8b43f7afc53196author juandebravo <[email protected]> 1353968043 +0100committer juandebravo <[email protected]> 1353968043 +0100

index on master: dc46efc add unittest main



λ git stash list

λ cat .git/refs/stash

stash@{0}: WIP on master: dc46efc add unittest main

7cf1d41c1352d4df176d53d566354b8ca4d517cd



1


3 git tips & tricks

git internals


WORK WITH MORE THAN ONE REMOTE


3. git tips and tricks Page 110

$ git clone [email protected]:jdbd/txsip.git

1) Clone repository

0) Fork repository

$ git remote -vorigin [email protected]:jdbd/txsip.git (fetch)origin [email protected]:jdbd/txsip.git (push)


3. git tips and tricks 2 Page 111

$ git remote -vorigin [email protected]:jdbd/txsip.git (fetch)origin [email protected]:jdbd/txsip.git (push)upstream [email protected]:ggb/txsip.git (fetch)upstream [email protected]:ggb/txsip.git (push)

$ git remote add upstream [email protected]:ggb/txsip.git

2) Add upstream repository



$ git checkout -b task/minor_changes..git commit -m "bla bla"git push origin task/minor_changes

3) Work...

4) Pull request...



5) Your pull request is accepted by the upstream repo owner (thanks @ggb)



6) Fetch and sync changes$ git fetch upstream$ git checkout master$ git merge upstream/master

Updating c87ea52..eec65b1Fast-forward .gitignore | 1 + README.md | 2 +- libs/pjsua.pyc | Bin 104192 -> 100106 bytes txsip/__init__.py | 1 + txsip.py => txsip/main.py | 0 5 files changed, 3 insertions(+), 1 deletions(-) create mode 100644 .gitignore create mode 100644 txsip/__init__.py rename txsip.py => txsip/main.py (100%)



7) Push changes to origingit push origin mastergit lg

* eec65b1 - (HEAD, upstream/master, origin/master, origin/HEAD, master) Merge pull request #2 from jdbd/task/minor_|\ | * f9e29a5 - (origin/task/minor_changes) PDI folder structure - juandebravo (4 days ago)| * 4b653ac - fix typo - juandebravo (4 days ago)| * 100a3db - create .gitignore file - juandebravo (4 days ago)| * 41ea559 - remove *.pyc - juandebravo (4 days ago)|/ * c87ea52 - UPDATE packet size limit in pjsip - ggb (5 weeks ago)



HIGHLIGHT YOUR SHELL





USE .GITCONFIG



[user] name = juandebravo email = [email protected][alias] lg= log --graph --abbrev-commit --date=relative --all co = checkout br = branch ci = commit st = status db = branch -d unstage = reset HEAD -- last = log -1 HEAD release = !"sh -c 'git checkout -b release/$1' develop"





git internalsgit advanced topics

Juan de Bravo Questions?


Dev conf git_lecture

Documents

git internals1

git objects1

git init

git blobgit internalsdevcon

git treesgit internalsdevcon

git format object type

git object format object

foo foo hello