What makes a linter a formatter

[mmorel-35]

I see that the following linters are now defined as formatters
- gci
- gofmt
- gofumpt
- goimports
- golines

but two others that are dealing with whitespaces stays linters but not formatters

• whitespace
• wsl

I'd like to understand that distinction because I would have expected whitespace linters to be defined as formatter.

[ldez]

Hello,

there are 2 main differences:

• the notion of "style" vs "format"
• their implementations

This is the same difference as govet and gofmt.

wsl, whitespace, etc. are analyzers (analysis.Analyzer), and are related to style (they don't format the code but detect style issues).

gofmt, goimports, etc. are formatters (func(src []byte) []byte), and are related to format (they don't detect style problems, they just apply a format).

We have a "bridge" to use formatters as a linter, but it's more of a convenience than their intended use.

FYI, technically, gci, gofmt, gofumpt, goimports have never been "linters"; they were just wrapped to fake a linter behavior.

[alexandear]

@ldez Maybe we should add this question/answer to the FAQ page?

[ldez]

For now, this is not a frequent question.

[buzzdan]

@ldez are formatters also count as linters?
i mean, if my code wasnt formatted and linter runs, will it fail linting ?

[bombsimon]

You will have to run fmt if you don't have a config:

› golangci-lint run --no-config --default all
0 issues.

› echo $?
0

› golangci-lint fmt --no-config --diff
diff /home/simon/tmp/x/main.go.orig /home/simon/tmp/x/main.go
--- /home/simon/tmp/x/main.go.orig
+++ /home/simon/tmp/x/main.go
@@ -2,5 +2,5 @@
 package main

 func main() {
-    _ = 1
+       _ = 1
 }

› echo $?
1

But if you have a config like this:

---
version: 2
linters:
  default: none

formatters:
  enable:
    - gofmt

it will run automatically:

› golangci-lint run
main.go:4:1: File is not properly formatted (gofmt)
    _ = 1
^
1 issues:
* gofmt: 1

[ldez]

i mean, if my code wasnt formatted and linter runs, will it fail linting ?

Yes, the formatters defined inside the configuration are used as linters automatically.