Allow multiple main in same folder (for adhoc scripts, now fails with "main redeclared...")

[timonwong]

Is your feature request related to a problem? Please describe.

Sometimes we include several ad-hoc golang scripts in same folder, for example "scripts", to do ad-hoc jobs (executed them with go run).
However, since golangci-lint cannot just ignore "packages", it will fail like this:

WARN [runner] Can't run linter goanalysis_metalinter: S1004: failed prerequisites: [(inspect@xxx, isgenerated@xxx): analysis skipped: errors in package: [xxx/script-1.go:13:6: main redeclared in this block xxx/script-2.go:13:6:       other declaration of main]] 
ERRO Running error: S1004: failed prerequisites: [(inspect@xxx, isgenerated@xxx): analysis skipped: errors in package: [xxx/script-1.go:13:6: main redeclared in this block xxx/script-2.go:13:6:         other declaration of main]] 

Currently, as a workaround, we run golangci-lint individually for each valid packages, and then run golangci-lint for those scripts one by one, this is sometimes cumbersome so I think it's better to do it in golangci-lint.

Describe the solution you'd like

Add an option to not treat these directories as packages, instead, scan them as golang files individually.

Additional context

#489 (comment)

[boring-cyborg]

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[SVilgelm]

you can use skip-dirs in main golangci.yml: https://github.com/golangci/golangci-lint/blob/master/.golangci.yml#L137

and add individual golangci.yml for every sub project and just run all of them

[timonwong]

you can use skip-dirs in main golangci.yml: https://github.com/golangci/golangci-lint/blob/master/.golangci.yml#L137

skip-dirs won't work since the loader will include those packages first.

So provided the following project structure:

.
├── .golanci.yml
├── cmd
│   └── demo-server
│       └── main.go
├── go.mod
├── pkg
│   └── httputil
│       └── httputil.go
└── scripts
    ├── script1.go
    └── script2.go

In order to make golangci-lint work, we need to run the following respectively:

• golangci-lint run ./cmd/... # package
• golangci-lint run ./pkg/... # package
• golangci-lint run scripts/script1.go # file
• golangci-lint run scripts/script1.go # file

And this is not straight forward

[SVilgelm]

because you need to put script1.go and script2.go into different packages

scripts
|-- script1
|    |-- script1.go
|-- script2
     |-- script2.go

you structure incorrect, you cannot declare functions/variable with same name in same package. Just put to different packages

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[vegerot]

you structure incorrect,

@SVilgelm can you explain how it's incorrect? I can have multiple main functions in the same main package in the same directory and go run them fine

[ldez]

can you explain how it's incorrect?

golangci-lint works by package, it's the same thing as run go run . (or go run ./scripts/).

Also, you can create multiple main functions but you cannot call them by package because all those files are a part of the same package.

From the point of view of a package, it's impossible to have multiple functions/variables with the same name.

Go is an app-oriented language, not a script-oriented language, so it's a bad practice to have a main package with multiple main functions.