Propose adding a handful of sections to the CodeReviewComments page. The sections that follow provide advice given during Go readability reviews at Google.

Import _

Packages that are imported only for their side effects (using the syntax import _ "pkg") should only be imported in the main package of a program, or in tests that require them.

Avoid blank imports in library packages, even if the library indirectly depends on them. Containing side-effect imports in the main package helps control dependencies, and makes it possible to write tests that rely on a different side-effect without conflict.

If you create a library package that indirectly depends on a side-effect import, leave a comment reminding users to import that package in their main package.

Switch Break

Avoid the use of redundant break statements without target labels at the ends of switch clauses. Unlike in C or Java, switch clauses in Go automatically break, and a fallthrough statement is needed to achieve the C-style behavior.

Use a comment if you want to clarify the purpose of an empty clause.

Prefer:

switch x {
case "A", "B":
  buf.WriteString(x)
case "C":
  // Handled outside of the switch statement
default:
  return fmt.Errorf("unknown value: %q", x)
}

and not:

switch x {
case "A", "B":
  buf.WriteString(x)
  break  // Redundant
case "C":
  break // Redundant
default:
  return fmt.Errorf("unknown value: %q", x)
}

Type Aliases

Use a type definition (type T1 T2) to define a new type.

Use an alias declaration (type T1 = T2) to refer to an existing type without defining a new type.

Prefer type definitions over alias declarations.

Use %q

Go's format functions (fmt.Printf and friends) have a %q verb which prints a string inside quotation marks. It should be used in preference to doing the equivalent manually.

Prefer:

 fmt.Printf("value %q looks like English text", someText)

and not:

 fmt.Printf("value '%s' looks like English text", someText)

Also, note that using %q is a good idea in output intended for humans where the input value could possibly be empty. It can be very hard to notice a silent empty string, but "" stands out clearly as such.