[FEATURE] Configure spotless to handle newline linting in lieu of linelint

[dbwiddis]

Is your feature request related to a problem?

Issue #46 requested to add linelint to this repo matching OS #2857. I commented that it could have been done with spotless, but there was no further discussion and linelint was implemented as a GitHub Action.

This presents a frustrating situation for users, as linelint does not automatically fix errors. (The actual program does but this is not helpful from a GHA.). There is no real way to proactively lint files from the command line, or even check them, prior to submitting a PR, seeing a failing lint check, and then manually fixing the affected files.

I would like to re-raise the issue of using a single linter (spotless) which not only detects but auto-fixes these issues.

Contrary to the comments on OS #2857, it can handle all sorts of files and is not limited to just .java files. See for example here where .gradle and .md (and other) files are included:

  format 'misc', {
    // define the files to apply `misc` to
    target '*.gradle', '*.md', '.gitignore'

    // define the steps to apply to those files
    trimTrailingWhitespace()
    indentWithTabs() // or spaces. Takes an integer argument if you don't like 4
    endWithNewline()
  }

What solution would you like?

Remove linelint and configure spotless as above (but with spaces, not tabs).

Consider making the same change in OpenSearch for the same reasons and with a much wider impact.

What alternatives have you considered?

Building linelint on my local machine so I can take advantage of its auto-fix features. I already tried to install with homebrew but it's not set up there and the effort vs. time saved isn't worth building it myself on multiple machines; or even if it was, that would only help me.

Do you have any additional context?

I plan on adding more .svg files documenting designs, and they don't include newlines by default. I don't want to manually edit .svg files. I don't want to upload .svg files and get yelled at by failed GHA. I don't want to keep adding exclusions to linelint.yml. I just want to run ./gradlew spotlessApply which I already do, and not have to think about end of file newlines ever again.

[owaiskazi19]

@peternied do we have any advantage of using the current line linter as compared to Spotless linelint? If not, then we are good to go with Spotless :)

[dbwiddis]

https://github.com/opensearch-project/opensearch-sdk-java/runs/8199437661?check_suite_focus=true

Note for future me to reduce that 11 minutes to 2 minutes until this is changed, ed has a nice trick:

$ ed -s openapi.json <<< w
newline appended