Linters are the tools that help us write better source code. The first Linter was developed in 1978, as a means to analyze source code. Since then, Linters have evolved to perform tasks beyond their original specification. Nowadays, Linters can “perform Static Analysis, enforce configuration flags, check for compliance with a given style-guide or security rule, and a lot more.” Go’s standard library ships with a command gofmt , gofmt performs static analysis on specified source code. The command can also rewrite source code to improve formatting. gofmt is a Go Linter.

The OSS community offers its set of Go Linters as well. One of my favorite OSS projects is go-ruleguard . I find it useful because Go code defines the rules dynamically. go-ruleguard has a custom command to perform source code analysis. To run the command, you need to specify the go source with the rules and the files to analyze. If used correctly, go-ruleguardis a powerful tool to master.

Writing a linter rule for golang

The first rule I wrote detects if strings are being appended together with the + operator. Joining strings this way is not efficient on a large scale, hence my motivation for writing this. I began by writing source code that would break the rule on purpose. Here is the content of file main.go :

Next, I’ll create a file named rules.go , it’ll house my Linter rules :