Detect go files as generated according to official rules

[ernestas2k]

Use officially accepted rules to detect golang generated files https://golang.org/s/generatedcode

Description

The rule dictates that a line matching ^// Code generated .* DO NOT EDIT\.$ can be anywhere in golang file.
I currently use github.com/deepmap/oapi-codegen that generates the following (valid according to the rules) file:

// Package api provides primitives to interact the openapi HTTP API.
//
// Code generated by github.com/deepmap/oapi-codegen DO NOT EDIT.
package api

// Error defines model for Error.
type Error struct {
...

Sample file for test taken from: https://github.com/deepmap/oapi-codegen/blob/master/examples/petstore-expanded/echo/api/petstore-types.gen.go
The project license (apache 2.0) https://github.com/deepmap/oapi-codegen/blob/master/LICENSE

Would be good to get such files ignored automatically by github when reviewing PRs.

This issue was raised and solved multiple times but wasn't merged.
Refs #3800 #2724

Checklist:

• I am adding new or changing current functionality
  • I have added or updated the tests for the new or changed functionality.

[pchaigno]

Thanks for improving this!

[pchaigno]

LGTM! Thanks @ernestas2k!

[lildude]

@ernestas2k Can you please add a note to the original post linking to the source of the sample file and the license it is covered by. Thanks.

[ernestas2k]

@ernestas2k Can you please add a note to the original post linking to the source of the sample file and the license it is covered by. Thanks.

The sample file is generated (using the mentioned tool) and located in private repo of mine. Should I find public sample file instead? Like this one https://github.com/deepmap/oapi-codegen/blob/master/examples/petstore-expanded/echo/api/petstore-server.gen.go ?

[lildude]

@ernestas2k yes please. We need to be able to verify sources in case there are any licensing issues in future.

[pchaigno]

@lildude Isn't posting here in a pull request the same as adding it to a public repository under a permissive license? I mean, it's literally what people are doing by posting here.

[lildude]

@pchaigno sort of. If the file isn't from a source with a verifiable open license, and the author isn't deemed "authoritative" at some point in the future by the owner of the code, it potentially opens GitHub up to legal battles.

I know this isn't the case now, but it's best and easier to be consistent across the board.

[lildude]

@ernestas2k if you're quick, I might just be able to squeeze this into the linguist release I'm currently testing.

[ernestas2k]

@lildude ok just a moment

[ernestas2k]

@lildude updated the PR code and the original post, let me know if any more changes would be valuable.

[lildude]

Thanks @ernestas2k 🙇