regexp.{Must}Compile{POSIX} should be called at once for performance.

You can get regexponce by go get command.

$ go get -u github.com/budougumi0617/regexponce/cmd/regexponce

regexponce run with go vet as below when Go is 1.12 and higher.

$ go vet -vettool=$(which regexponce) ./...

regexp.Compile is heavy, therefore the functions should be called jsut once in the process. Analyzer confirms that the below functions are not called multiple times.

• regexp.Compile
• regexp.CompilePOSIX
• regexp.MustCompile
• regexp.MustCompilePOSIX

• Called target functions in the package scope.
• Called target functions in init function.
• Called target functions in main function.
  • Except if they are called in for loop.
• Add staticcheck's style comments
  • //lint:ignore regexponce REASON

• Called target functions in normal function.
• Called target functions in for lop.

The warning sample is below.

package main

import (
    "fmt"
    "regexp"
)

func f() {
	var validID = regexp.MustCompile(`^[a-z]+\[[0-9]+\]$`) // want `regexp.MustCompile must be called only once at initialize`
	// lint:ignore regexponce allowed
	validID = regexp.MustCompile(`^[a-z]+\[[0-9]+\]$`) // OK because add specify comment.

	assign := regexp.MustCompile
	assign(`^[a-z]+\[[0-9]+\]$`) // want `regexp.MustCompile must be called only once at initialize`
}

func main() {
	var validID = regexp.MustCompile(`^[a-z]+\[[0-9]+\]$`) // OK because main function runs only once.

	for i := 0; i < 10; i++ {
		validID = regexp.MustCompile(`^[a-z]+\[[0-9]+\]$`) // want `regexp.MustCompile must be called only once at initialize`
	}
}

$ regexponce help regexponce
regexponce: Below functions should be called at once for performance.
- regexp.Compile
- regexp.MustCompile
- regexp.CompilePOSIX
- regexp.MustCompilePOSIX

Allow call in init, and main(except for in for loop) functions because each function is called only once.

1. Fork (https://github.com/budougumi0617/regexponce/fork)
2. Create a feature branch
3. Commit your changes
4. Rebase your local changes against the master branch
5. Run test suite with the go test ./... command and confirm that it passes
6. Run gofmt -s
7. Create new Pull Request

MIT

Yoichiro Shimizu(@budougumi0617)