mvn clean install adds files to presto-main/src

[elharo]

I've noticed that recently these new files keep showing up in my repo:

Untracked files:
(use "git add ..." to include in what will be committed)
presto-main/src/main/resources/webapp/dev/query_viewer.js
presto-main/src/main/resources/webapp/dist/

I think these belong instead in the generated-sources directory (or something like that; still need to fully debug and research this). I suspect they've been added as a result of #22645

[yhwang]

These untracked files are from the #22645 (but they were not added by the PR, the PR removed them from the sources):

presto-main/src/main/resources/webapp/dev/query_viewer.js
presto-main/src/main/resources/webapp/dist/

@ZacBlanco also informed me about this issue
The possible solutions are:

1. Add these files into .gitigonre
2. Modify the webpack to generate compiled JS to presto-main/target directory

For solution 2, it may need to tweak the webpack config to cover the dev scenarios. Need to make sure yarn watch, yarn serve work with the new JS location.

[elharo]

#1 is not really a solution. #2 is a maybe. In the past I've seen these sorts of tools use a generated-sources directory though at the moment, I can't find any docs about that. However we definitely should not generate anything into src/main. We need to put generated code somewhere mvn clean will delete it.

[yhwang]

@elharo

We need to put generated code somewhere mvn clean will delete it

That's option 2.

[elharo]

had to look in the maven-compiler-plugin source code but it likely belongs in

${project.build.directory}/generated-sources/

[yhwang]

FYI, Presto is following the Maven stadnard directory layout: https://maven.apache.org/guides/introduction/introduction-to-the-standard-directory-layout.html

[elharo]

Yes, and nothing in that layout is for generated code.

[yhwang]

for .js files, they are equal to .class which would go to target/classes