[Style] added branch

collects/scribblings/style/branch-and-commit.scrbl

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+#lang scribble/base
+
+@(require "shared.rkt")
+
+@title{Branch and Commit}
+
+@section{Commit}
+
+So what is the major lesson of this section? When you fix a bug, make sure
+ to commit (1) the code delta, (2) the new test case, and (3) the revised
+ docs (if applicable) in one batch. If the creation of a single commit is
+ too complex of if you wish to factor out one of the commits, please push
+ all pieces at once. That way the code base is always in a state where
+ code, tests, and documentation are in sync, and readers of commit messages
+ can evaluate changes completely.
+
+@section{No Commit ``Bombs'' Please}
+
+On occasion, you will find that you are spending a significant amount of
+ time working with someone else's code. To avoid potentially painful
+ merges, please (1) inform the author when you create the branch and (2)
+ set the mail hook @margin-note*{See Eli's write-up on using git in PLT for
+ information on the mechanics.} so that git sends a commit message to both
+ you and the original author. Furthermore, you should test your changes on
+ the actual code base. In some cases it is acceptable to delay such tests,
+ e.g., when you will not know for a long time whether the performance
+ implication allow a commit to the PLT repository.