fix: add warnings for unsupported feature flags (#18672)

[schastlivcev]

Description

There was no indication if you were using non-existent or unsupported feature flags at startup. This change brings log warnings about existence of such feature flags

Fixes #18672

Type of change

• Bugfix
• Feature

Checklist

• I have read the contribution guide: https://vaadin.com/docs/latest/guide/contributing/overview/
• I have added a description following the guideline.
• The issue is created in the corresponding repository and I have referenced it.
• I have added tests to ensure my change is effective and works as intended.
• New and existing tests are passing locally with my change.
• I have performed self-review and corrected misspellings.

[CLAassistant]

All committers have signed the CLA.

[schastlivcev]

Hi, I'm sorry for taking so long, have some questions:

1. I saw "expressBuild" feature flag in some .properties files, should I add it to the FeatureFlags class? Add a feature flag for Express Build #15375
2. I checked against the ids in the class, is it correct or is there another place to look?
3. Original issue was about the .properties file, should I expand it to the system properties?
4. Do I need to put a boolean check flag into a synchronized block?

[mshabarov]

Thanks for your contribution @schastlivcev !

Some suggestions:

1. ExpressBuild flag has been removed and isn't used anymore. It was related to pre-compiled bundles feature, but can be removed now from everywhere in Flow.
2. I think the com.vaadin.experimental. + flag's id is enough for matching.
3. Would be better to apply to system properties, as this might be a common case to set flags in CI for instance.

[github-actions]

Test Results

1 099 files  ±0  1 099 suites  ±0   1h 19m 50s ⏱️ -31s
7 012 tests +3  6 963 ✅ +3  49 💤 ±0  0 ❌ ±0 
7 356 runs  +4  7 295 ✅ +4  61 💤 ±0  0 ❌ ±0 

Results for commit b320073. ± Comparison against base commit 63e6dfd.

♻️ This comment has been updated with latest results.

[mshabarov]

@schastlivcev anything else you wanted to add? Otherwise, I'll merge this pull request.
Thanks again for contribution!

[vaadin-bot]

TC Format Checker Report - 12:39 - 19 - Apr

There are 2 files with format errors

• To see a complete report of formatting issues, download the differences file

• To fix the build, please run mvn formatter:format in your branch and commit the changes.

• Optionally you might add the following line in your .git/hooks/pre-commit file:

  mvn formatter:format
  

Here is the list of files with format issues in your PR:

flow-server/src/main/java/com/vaadin/experimental/FeatureFlags.java
flow-server/src/test/java/com/vaadin/experimental/FeatureFlagsTest.java

[mshabarov]

@schastlivcev could you please run mvn formatter:format and push changes? formatting blocks this PR and I cannot access your fork branch.

[sonarcloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarCloud

[schastlivcev]

Sorry for so long replies, lots of work. I'll deal with changes by the end of the week

[mshabarov]

Sorry for so long replies, lots of work. I'll deal with changes by the end of the week

Thanks! And no worries, let me know if you need any support.

[mshabarov]

Closed in favour of #19345.