Check if it is feasible to integrate ktlint as a rule set

[arturbosch]

pro:

• get fixes asap from ktlint
• more rules?

neg:

• different kotlinc versions
• two engines -> same work twice? -> shortcuts? invoke ktlint
• detekt additional formatting rules split

[arturbosch]

ktlint-standard-ruleset is not published to maven central as standalone artifact. Formatting rules were fixed and cleaned up for M11.

[shyiko]

@arturbosch fyi: http://search.maven.org/#search%7Cga%7C1%7Ca%3A%22ktlint-ruleset-standard%22

[arturbosch]

@shyiko nice thx. Did not find it on my own :)

[arturbosch]

KtLint uses the embeddable kotlin compiler, detekt not.
The new recommend way for formatting is to use the detektIdeaFormat task starting from M11.

[arturbosch]

Detekt now uses the embeddable compiler. A KtLint rule set is now feasible.

Idea:

• Create new rule set with wrappers around all KtLint rules
• Delete spacing, indentation and newline rules from detekt-formatting, just keep the extra rules which feature ast manipulation
• Users have now the choice between formatting with detektIdeaFormat and detektKtLintFormat

[vanniktech]

So the idea is to get rid of the formatting part in detekt (detekt-formatting) and leave it up to ktlint?

[arturbosch]

Yeah it would be best. I still do not know what to do with the formatting rules which ktlint does not have. Move them to StyleGuideProvider? Should detekt-rules also support autoCorrect? Should we leave detekt-formatting with all rules and integrate KtLint into that module? Create a new detekt-ktlint-module?

I think a hybrid detekt-formatting module would be best (low change costs). We leave all rules as they are and wait until Ktlint releases new rules or fixes. Then we act and wrap one after the other rules. What do you think?

[vanniktech]

I'm at the moment using both tools. Ktlint only for formatting and detekt for everything else. I'd assume that also the way to go for the future.

[arturbosch]

detekt/sonar-detekt#20

[arturbosch]

PoC: 18be6bc

Fairly easy to integrate.

[schalkms]

@arturbosch
I was scanning through the issue list. I think this feature is done, isn't it?

[arturbosch]

Yes, its done, some documentation is needed, but that can be done when we integrate the module into our CI, thanks for the reminder.

[dimsuz]

I am new to the project (just integrated it) and I'm a bit lost about role of ktlint in detekt.
So documentation would be helpful indeed.

I was researching why does detekt currently have to very similar rules NoWildcardImports and WildcardImport in its default config, so in the sources I discovered that one is coming from ktlint, another is "native"?

Is this ok, or should I report an issue (or I could submit a PR if you suggest me how this should be resolved).

[schalkms]

@dimsuz
Detekt provides a wrapper over Ktlint.
There’s actually some documentation regarding the ktlint integration here.
If you have any suggestions for improvement, please feel free to open an issue. We are grateful for PRs regarding detekt's documentation.

[idrisadetunmbi]

Not too sure I understand how this ktlint integration works. If I add the ktlint integration as a formatting ruleset, does it mean detekt will report formatting errors, and if I do not add it, it won't report them? Can I possibly run code formatting with detekt once I add the ktlint integration?

[schalkms]

@idrisadetunmbi I don't quite understand your question.
Detekt provides a wrapper over ktlint's rules with the formatting ruleset.
It depends on whether you have the autoCorrect and active setting set to true in the formatting ruleset.