Show warning if view_template method is not defined on Phlex class

[marcoroth]

I just upgraded Phlex to the latest 2.x rc in a Rails app and after bumping the phlex and phlex-rails versions the app would boot, the pages would render but all components would just render out as empty strings, since none of the components defined the new view_template method.

This pull request adds a warning to the rendered component output so that you know what's going on when you are upgrading.

Feel free to close this pull request if you feel like there's no place for this in Phlex.

[marcoroth]

FWIW, looks like the RuboCop config is broken (also happens on main):

Output

❯ bundle exec rubocop -A
Error: unrecognized cop or department Lint/DuplicateMatchPattern found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Lint/DuplicateBranch`?
unrecognized cop or department Lint/ItWithoutArgumentsInBlock found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Lint/LambdaWithoutLiteralBlock`?
unrecognized cop or department Lint/LiteralAssignmentInCondition found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Lint/AssignmentInCondition`?
unrecognized cop or department Lint/RedundantRegexpQuantifiers found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Lint/RedundantCopEnableDirective`?
unrecognized cop or department Style/ComparableClamp found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Style/Sample`?
unrecognized cop or department Style/DirEmpty found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Style/Strip`?
unrecognized cop or department Style/ExactRegexpMatch found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Style/RedundantRegexpCharacterClass`?
unrecognized cop or department Style/RedundantArrayConstructor found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Style/RedundantEach`?
unrecognized cop or department Style/RedundantCurrentDirectoryInPath found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Style/RedundantConditional`?
unrecognized cop or department Style/RedundantFilterChain found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Style/RedundantInterpolation`?
unrecognized cop or department Style/RedundantHeredocDelimiterQuotes found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Style/RedundantFileExtensionInRequire`?
unrecognized cop or department Style/RedundantLineContinuation found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Style/RedundantCondition`?
unrecognized cop or department Style/RedundantRegexpArgument found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Style/RedundantRegexpEscape`, `Style/RedundantArgument`, `Style/RedundantSelfAssignment`?
unrecognized cop or department Style/RedundantRegexpConstructor found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Style/RedundantRegexpEscape`?
unrecognized cop or department Style/SendWithLiteralMethodName found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Style/TrailingMethodEndStatement`?
unrecognized cop or department Style/SingleLineDoEndBlock found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Style/SingleLineMethods`?
unrecognized cop or department Style/SuperArguments found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Style/PerlBackrefs`?
unrecognized cop or department Style/SuperWithArgsParentheses found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Style/DefWithParentheses`?
unrecognized cop or department Style/YAMLFileRead found in .rubocop-https---www-goodcop-style-base-yml
Did you mean `Style/FileRead`?

[joeldrapper]

Thank you @marcoroth 🙏