Git父母和祖先之间的逻辑区别是什么 [英] Git what is the logical difference between parent and ancestor

问题描述

我知道我可以找到许多有关HEAD^和HEAD~

I know I can find dozens of questions about the difference between HEAD^ and HEAD~

• ~指定ancestors
• ^指定parents

• ~ specifies ancestors
• ^ specifies parents

我的问题是关于parents和ancestors含义的区别.对我而言，父母与祖先相同.

My question is about the difference of meaning of parents and ancestors. for me parent is the same as ancestor.

父母与祖先之间的逻辑区别是什么?

What is the logical difference between parent and ancestor?

Git中的HEAD ^和HEAD〜有什么区别没有回答我的问题，我的问题是关于这两个术语的逻辑含义.

What's the difference between HEAD^ and HEAD~ in Git? doesn't answer my question, my question is about the logical meaning of the two terms.

推荐答案

区别是垂直和水平问题.

The difference is a bit of a vertical vs horizontal matter.

在Git中，提交是链接列表的一种，每个提交都引用一个父提交或一个多个父提交.

In Git, commits are a type of linked list, each commit has a reference to a parent commit, or to multiple parent commits.

通过~访问父级或祖父母级:

Accessing a parent, or a grand-parent, is done with ~:

• ~是提交的直接父级，
• ~2(或~~)是祖父母
• 依此类推

• ~ is the direct parent of a commit,
• ~2 (or ~~) is the grand-parent
• and so on

这是垂直的一面，如果您查看日志，则使用~将使您深入了解提交.

This is the vertical side, if you look at a log, using ~ will make you go down through the commits.

现在，当您合并两个分支时，它将进行合并提交.根据定义，合并提交是将两个或多个分支合并在一起.因此，合并提交将有两个或多个父级.

Now, when you merge two branches, it makes a merge commit. A merge commit, by definition, is merging two, or more, branches together. So the merge commit will have two or more parents.

在合并提交中，如果要访问不同的父级，请使用^(实际上看起来像是两个分支的合并).

From the merge commit, if you want to access different parents, you use ^ (it actually looks like a merge of two branches).

因此请考虑日志的这一部分:

So consider this part of log:

*   39a2f899 (HEAD)
|\  
| * e2e7d241 (BRANCH)
| * caf13dc1
| * 609a9715
|/  
*   663e09ff

如果要访问BRANCH的父提交，则可以执行BRANCH~或e2e7d241~，这将给出caf13dc1.现在，如果您要访问HEAD的父级并执行HEAD~，它将为您提供663e09ff(分支开始之前的提交).

If you want to access the parent commit of BRANCH, you would do BRANCH~, or e2e7d241~, which would give caf13dc1. Now if you want to access the parent of HEAD, and do HEAD~, it will give you 663e09ff (the commit before the branch started).

但是，如果您想访问合并分支的提交链，那就是^在游戏中出现的位置，您可以执行HEAD^2，说"HEAD的第二父级"(而不是父级的父级)

But if you want to access the chain of commits of the merged branch, that's where ^ comes in the game, you would do HEAD^2, to say the "second parent of HEAD" (not the parent's parent).

您当然可以组合它们，在同一张图中，HEAD^2~是HEAD的第二个父级(^2)的父级(~)，caf13dc1

You can of course combine them, in the same graph, HEAD^2~ is the parent (~) of the second parent (^2) of HEAD, which is caf13dc1

顺便说一句，每个提交至少有1个父对象，因此commit^始终与commit~相同.另一方面，如果提交具有单亲(不是合并提交)，则commit^2将返回错误.

Incidentally, every commit has at least 1 parent, so commit^ is always the same as commit~. On the other hand, if a commit has a single parent (it is not a merge commit), commit^2 will return an error.

总而言之，您可以使用^访问合并的不同父级，并且可以使用~访问生成的提交.

To sum up, you access different parents of a merge with ^ and you access generations of commits with ~.

可以通过以下更复杂的合并来说明(一次合并4个分支):

It can be illustrated as follow with a more complex merge (of 4 branches merged at once):

----------> use ^ to go through the parents of the merge
|
|   *-----.   6af2936d
|   |\ \ \ \  
|   | | | | * 20d6fb23 BRANCH1
|   | | | * | e589d446 BRANCH2
|   | | | * | ec6088bd
|   | | | |/  
|   | | * | 38dcecfa BRANCH3
|   | | |/  
|   | * | 698c3daa BRANCH4
|   | |/  
|   |/  
|   *   2d97958e
|   |\  
|   | * 8989f1d3
|   | * d907cb7a
|   |/  
|   *   af368002
V
use ~ to go this way (through the ancestors)

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