Merge branch 'doc/extend-code-review-guidelines' into 'master'

Extend code review docs with chapter about the right balance

[ci skip]

See merge request !7838

doc/development/code_review.md

@@ -74,6 +74,32 @@ experience, refactors the existing code). Then:
 - If you set the MR to "Merge When Build Succeeds", you should take over
   subsequent revisions for anything that would be spotted after that.
 
+## The right balance
+
+One of the most difficult things during code review is finding the right
+balance in how deep the reviewer can interfere with the code created by a
+reviewee.
+
+- Learning how to find the right balance takes time; that is why we have
+  minibosses that become merge request endbosses after some time spent on
+  reviewing merge requests.
+- Finding bugs and improving code style is important, but thinking about good
+  design is important as well. Building abstractions and good design is what
+  makes it possible to hide complexity and makes future changes easier.
+- Asking the reviewee to change the design sometimes means the complete rewrite
+  of the contributed code. It's usually a good idea to ask another merge
+  request endboss before doing it, but have the courage to do it when you
+  believe it is important.
+- There is a difference in doing things right and doing things right now.
+  Ideally, we should do the former, but in the real world we need the latter as
+  well. A good example is a security fix which should be released as soon as
+  possible. Asking the reviewee to do the major refactoring in the merge
+  request that is an urgent fix should be avoided.
+- Doing things well today is usually better than doing something perfectly
+  tomorrow. Shipping a kludge today is usually worse than doing something well
+  tomorrow. When you are not able to find the right balance, ask other people
+  about their opinion.
+
 ## Credits
 
 Largely based on the [thoughtbot code review guide].