内部構造から学ぶGit

社内勉強会資料

Transcript

1. ಺෦ߏ଄͔ΒֶͿGit
   @eichisanden
   

   View Slide

2. f5aecbff04f484dcf74e14f
   c6961da0a8b6d43ad
   

   View Slide

3. Gitͱ͍͑͹ɺSha1ϋογϡ40ܻ
   

   View Slide

4. commit ff86faf2fa02bc21933c9e1dcc75c8d81b3e104a
   Merge: 8f8d0ec 552a736
   Author: Taro
   Date: Wed Aug 19 14:49:37 2015 -0700
   Bugfix xxx
   commit 8f8d0ecfde871144ae839876039fe4e8fed75a9c
   Author: Taro
   Date: Wed Aug 19 14:46:09 2015 -0700
   Refactoring xxx
   commit 011710a315a5e4157e882880fe77798f8d4adde0
   Merge: 8c9155e 09bb652
   Author: Taro
   Date: Wed Aug 19 14:48:56 2015 -0700
   Merge branch 'todo'
   git logͷ݁Ռ
   

   View Slide

5. Q. ԿͰsha1ϋογϡͳͷʁ
   svnΈ͍ͨʹγʔέϯεͷํ͕ྑ͘ͳ
   ͘ͳ͍ʁ
   

   View Slide

6. A. Git͸DVCSʢ෼ࢄܕόʔ
   δϣϯ؅ཧγεςϜʣ͔ͩΒ
   

   View Slide

7. ϦϏδϣϯ1ͬͯԿΑ
   தԝϦϙδτϦ
   "͞ΜͷϩʔΧϧ
   #͞ΜͷϩʔΧϧ
   
   
   
   
   
   →෼ࢄ؀ڥશମͰϢχʔΫͰ͋Δඞཁ͕͋Δ
   

   View Slide

8. ෼ࢄܕ͡Όͳ͔ͬͨͱͯ͠΋ɺ
   Git͸ίϛοτͷྺ࢙ͷվมʹ׮༰
   ͳͷͰɺγʔέϯεNo.͸߹Θͳ͍
   

   View Slide

9. Q. ຖ౓40ܻ΋ࢦఆ͠ͳ͍ͱμϝͳ
   ͷʁ
   

   View Slide

10. A. ඃΒͳ͚Ε͹ɺઌ಄4ܻͰOK
    େ͖ΊͷϦϙδτϦͰ΋6ܻࢦఆͰ͍͚Δ
    

    View Slide

11. Q. ϋογϡ஋͸Ͳ͏΍ܾͬͯ·Δ
    ͷʁ
    

    View Slide

12. A. ίϛοτͷ಺༰Ͱܾ·Δ
    

    View Slide

13. Q. ϋογϡ஋͕ඃΔ͡Όͳ͍ʁ
    

    View Slide

14. A. ඃΔʢՄೳੑ͸͋Δʣ
    

    View Slide

15. Ͱ΋িಥͷՄೳੑ͸Ұஹೋઍԯͷͦ
    ͷ·ͨҰஹഒ
    

    View Slide

16. ஍ٿ্ͷཻ࠭ͷઍೋඦഒͷ֬཰
    ʙPro Git 6ষΑΓʙ
    

    View Slide

17. ී௨ʹ࢖͏෼ʹ͸ؾʹ͢Δඞཁͳ͍
    

    View Slide

18. gitͷΦϒδΣΫτͷछྨ
    commit
    tree
    blob
    tagʢࠓճ͸࿩͠·ͤΜʣ
    

    View Slide

19. Πϝʔδਤ
    HJUMPHͰΈͯͨͷ͸
    ͜͜ͷҰཡ
    

    View Slide

20. Πϝʔδਤ
    ଞͷΦϒδΣΫτ΋Ұҙͳϋο
    γϡΛ͍࣋ͬͯΔ
    

    View Slide

21. git cat-file ίϚϯυͰΦϒδΣΫ
    τͷதΛ೷͍ͯΈΑ͏
    

    View Slide

22. commitΦϒδΣΫτ
    $ git cat-file -p ff86fa
    tree c95970c3507b89fe43181df983f73c8f1db262fb
    parent 8f8d0ecfde871144ae839876039fe4e8fed75a9c
    parent 552a736de775994570570a0514f24e32686afbe0
    author Taro 1440020977 -0700
    committer Taro 1440020977 -0700
    Bugfix: xxx
    

    View Slide

23. treeΦϒδΣΫτ
    $ git cat-file -p c95970
    100644 blob 5e98806c6cc246acef5f539ae191710a0c06ad3f .gitattributes
    100644 blob a685ec1fb0ca49607431a65f1ccf035bb9b95a3a .gitignore
    100644 blob ece2951a2b1e1cdd611c7dc371e50501d416d1f8 .mailmap
    100644 blob 536e55524db72bd2acf175208aef4f3dfc148d42 COPYING
    040000 tree dbb0cc4bf1e93167118aa39e57c8b7efa9113598 Documentation
    100755 blob fc45283501a3b004edabc55781b486b37509dd37 GIT-VERSION-GEN
    ϑΝΠϧͱϑΥϧμͷ৘ใΛ
    อ͍࣋ͯ͠Δɻ
    

    View Slide

24. blobΦϒδΣΫτ
    $ git cat-file -p 4223f1
    package main
    import “fmt”
    fun main() {
    fmt.Printf(“Hello World”)
    }
    ಡΊΔʂಡΊΔͧʂʂ
    

    View Slide

25. Q. GitͷΦϒδΣΫτ͸Ͳ͜ʹอଘ
    ͞Ε͍ͯΔͷʁ
    

    View Slide

26. A. .gitϑΥϧμͷத
    

    View Slide

27. GitͷϑΥϧμߏ੒
    .git
    !"" HEAD ←HEAD͕Ͳ͜Λࢦ͍ࣔͯ͠͠Δ
    !"" config ←จࣈ௨ΓઃఆϑΝΠϧ
    !"" description
    !"" hooks ←hookεΫϦϓτ
    !"" info
    # %"" exclude
    !"" objects ←͜͜ʹΦϒδΣΫτ͕ೖ͍ͬͯΔ
    # !"" 22
    # # %"" 62de0c121f22df8e78f5a37d6e114fd322c0b0
    # !"" 3e
    # # %"" 2799e0729c58acb86bb40f19c8cb4b2b4f8e96
    # !"" 46
    # # %"" d2987acc571a47f9e69b585eb833f6e903b2cc
    # !"" 6c
    # # %"" c84aae39643fdb94d1699b74b07e2c6500cbaf
    # !"" info
    # %"" pack
    %"" refs
    !"" heads
    %"" tags
    8 directories, 13 files
    

    View Slide

28. Q. શ͘ಉ͡಺༰ͷϑΝΠϧ͕͋ͬͨ
    ΒΦϒδΣΫτ͸ͲͷΑ͏ʹ֨ೲ͞
    ΕΔͷʁ
    

    View Slide

29. ಉ͡಺༰ͷϑΝΠϧΛ࡞੒ͯ͠ΈΔ
    $ echo "hoge" > a.txt
    $ echo "hoge" > b.txt
    $ git add .
    $ git commit -m 'add a.txt and b.txt'
    [master (root-commit) 6cc84aa] add a.txt and b.txt
    2 files changed, 2 insertions(+)
    create mode 100644 a.txt
    create mode 100644 b.txt
    $ git cat-file -p 6cc84aa
    tree f5aecbff04f484dcf74e14fc6961da0a8b6d43ad
    author eichisanden 1440425753 +0900
    committer eichisanden 1440425753 +0900
    add a.txt and b.txt
    $ git cat-file -p f5aecbff
    100644 blob 2262de0c121f22df8e78f5a37d6e114fd322c0b0 a.txt
    100644 blob 2262de0c121f22df8e78f5a37d6e114fd322c0b0 b.txt
    $ git cat-file -p 2262
    hoge
    ϋογϡ͸ಉ͡஋ͳͷͰແବͳΦ
    ϒδΣΫτ͸࡞ΒΕͳ͍ʂ
    

    View Slide

30. ϑΝΠϧ໊͕ҧ͓͏͕ɺ
    อଘϑΥϧμ͕ҧ͓͏͕ɺ
    ಺༰͕ಉ͡ͳΒಉ͡ϋογϡʹͳΔʂ
    

    View Slide

31. ϋογϡ஋͕িಥͨ͠ͱ͖΋Git͸
    ಉ͡ಈ͖Λ͢Δ͸ͣ
    ʢલड़ͷ௨Γɺى͜Γಘͳ͍Ͱ͕͢ʣ
    

    View Slide

32. Q. ϑΝΠϧΛࠩ෼Ͱ؅ཧ͠ͳ͍ͱɺ
    ͑Β͍༰ྔΛ৯͏ͷͰ͸ʁ
    

    View Slide

33. ͔֬ʹcommit(git add)ͨ͠
    ௚ޙ͸༰ྔΛ৯͏
    

    View Slide

34. ͨͩɺGCͰpackfileʹҠಈ͞Ε༰ྔ͸ݮΔͷͰେৎ෉
    .git
    !"" HEAD ←HEAD͕Ͳ͜Λࢦ͍ࣔͯ͠͠Δ
    !"" config ←จࣈ௨ΓઃఆϑΝΠϧ
    !"" description
    !"" hooks ←hookεΫϦϓτ
    !"" info
    # %"" exclude
    !"" objects
    # !"" 22
    # # %"" 62de0c121f22df8e78f5a37d6e114fd322c0b0
    # !"" 3e
    # # %"" 2799e0729c58acb86bb40f19c8cb4b2b4f8e96
    # !"" 46
    # # %"" d2987acc571a47f9e69b585eb833f6e903b2cc
    # !"" 6c
    # # %"" c84aae39643fdb94d1699b74b07e2c6500cbaf
    # !"" info
    # %"" pack ←͜͜ʹҠಈ͞ΕΔ
    %"" refs
    !"" heads
    %"" tags
    8 directories, 13 files
    

    View Slide

35. ໌ࣔతʹgit gcίϚϯυΛଧͨͳͯ͘΋ɺ
    git pushͱ͔ͷλΠϛϯάͰউखʹ΍ͬ
    ͯ͘ΕΔͷͰɺීஈ͸ҙࣝ͠ͳͯ͘OK
    

    View Slide

36. ಺෦ߏ଄Λ஌ΔͱgitΛ࢖͏ͷ
    ָ͕͘͠ͳΔ͔΋
    

    View Slide

37. ͝੩ௌ͋Γ͕ͱ͏͍͟͝·ͨ͠
    

    View Slide