Hi Tor,

Are there any instructions on how to add custom lint rules to Android 
Studio 1.4+ where it'd underline problematic areas within the IDE? I'm 
unable to figure it out even when looking at  the Analyze menu since I see 
no signs of any of the custom rules' existence within the menu.

Thanks!

On Monday, July 20, 2015 at 8:10:32 AM UTC-7, Tor Norbye wrote:
>
> Hi!
>>
>> My team has been working on integration some custom rules in our build 
>> process, and we have a few questions:
>>
>> - Is it possible to enable custom rules to run within Android Studio and 
>> highlight errors like built-in rules do?
>>
>
> Yes -- but only in Studio 1.4 which we'll put in canary as soon as 1.3 
> goes stable (we're at RC3 now.)  
>
> The reason custom lint rules do not show up in the IDE is that the IDE, 
> what you see running are really IntelliJ inspections. We wrap each lint 
> rule as an IDE inspection. And IDE inspections have to be registered 
> *statically* (in a plugin XML registration file). For all the builtin lint 
> rules, we've done this. But we recently fixed this:
> https://android-review.googlesource.com/#/c/158054/
> https://android-review.googlesource.com/#/c/157894/
>
> Note that there is one limitation though: Normally, in the Analyze window, 
> you get to see the full explanation text for the issue. That doesn't work 
> for third party rules. For custom rules, these will all be using a common 
> category and explanation (Third party Inspection or something like that), 
> and the explanation says that to see each full description to run Gradle's 
> lint target to get the HTML report with full explanations.  So, it's really 
> important that the error message itself be pretty descriptive. 
>
> - Is it possible (and practical!) to run Android Lint on non Android java 
>> projects?
>>
>
> It probably doesn't work, since there are a number of assumptions for 
> example that a manifest exist. Note however that lint *should* handle the 
> case where you are using a non-Android library module. It will still look 
> for problems in that non-Android module. So perhaps you could just create a 
> dummy Android app module referencing the non-Android library for this case?
>
> Note however that lint *doesn't* try to duplicate all the "general" 
> programming checks done by most IDEs -- assignment in conditional, etc. 
> Instead it focuses exclusively on flagging just Android-specific issues. 
> The idea was that IDEs and CI plugins already do a pretty good job checking 
> for general Java issues so let's not (a) duplicate effort and (b) have the 
> user end up with 2 sets of error messages for each error.
>
> - We are generating our custom lint jar as part of the build, and declare 
>> a dependent task to all lint tasks that makes it available to the lint 
>> tool. ANDROID_LINT_JARS is not convenient for us, since we can't modify an 
>> env variable from within the process, and the home directory won't work in 
>> shared servers. Copying the jar file into ${buildDir}/lint/lint.jar works, 
>> but it feels hacky. What is your recommendation? Also, would it be possible 
>> to add a list of custom rule jar files to lintOptions?
>>
>
> The best way for this to work is for you to inject your custom rules lint 
> jars by using the exact name "lint.jar", and then packaging this inside a 
> library AAR file that your project depends on. When lint runs on your 
> project, it gathers custom rules provided for any libraries your project is 
> using, if those libraries provide custom rules (and the way to do that is 
> to include them in the AAR payload using that exact location and name 
> inside the AAR file (which is just a .zip).
>
> Longer term we'd like to make it easy to create lint custom rules by just 
> having a new lint source set in your project (next to src/main/java, 
> src/main/test, etc we'd have src/main/lint), and those lint sources would 
> automatically be compiled with the lint API dependencies, and packaged into 
> the AAR (or if in an app module, be used when lintint this project.)
>
> But note that none of this is automated yet; primarily because the lint 
> API is not yet stable, and will probably change a bit more before we get 
> there.
>  
>
>> - I couldn't find a way to pass configuration parameters for my rules 
>> through the Lint options and I have been using Java system properties, but 
>> it feels ugly. It would be great to be able to configure rules in the lint 
>> configuration file. What is your recommendation for passing configuration 
>> into custom lint rules?
>>
>
> I agree, it's ugly, but there isn't a better way to do it yet.
>  
>
>> - Lint tries to load rules from every jar file in the lint directory, 
>> making it impossible for me to add dependent jar files. Is there a way to 
>> use custom rule jar files that have external dependencies?
>>
>
> Right now you'll need to use jarjar to include your dependencies (other 
> than lint's built-in dependencies) with your custom rule inside the same 
> jar. That's necessary because there isn't a way to describe what jars it 
> needs and have all the different lint-embedding contexts (studio/intellij, 
> gradle, command line script, eclipse) find and load it with a suitable 
> class loader.
>   
>
>> - Your sample code doesn't include support for unit tests, which would be 
>> really useful for debugging rules. How can I set them up?
>>
>
> There's a lint-tests AAR artifact now which makes this better, but sadly 
> it depends on another library, testutils, which wasn't published right, so 
> it doesn't work at the moment. As soon as that's republished (hopefully as 
> part of the 1.3 push) I'll update the sample which makes it trivial to unit 
> test lint checks.
>
> Also, I have a couple of minor questions about writing the rules 
>> themselves:
>>
>> - ResolvedClass has getMethods() but not getFields() (which would be 
>> useful, for example, to validate immutability). Is that an intentional 
>> omission?
>>
>
> No, that was not intentional! I've added it here:
> https://android-review.googlesource.com/160382
> https://android-review.googlesource.com/160391
>  
>
>> - applicableSuperClasses() can't be used with generic base classes, since 
>> the Java visitor seems to check against the full signature (which includes 
>> type parameters). We are working around this by selecting all classes 
>> instead and checking manually, but it seems wasteful. Would it make sense 
>> for the visitor to look up the class name as well?
>>
>
> Yes - that was not intentional, it should be using the raw type there. 
> Fixed by https://android-review.googlesource.com/160420 .
>  
>
>> - Super minor nit: Lint only admits "//noinspection" to disable issues, 
>> while AS will also take "// noinspection". We've been using the latter, and 
>> it took me a while to figure out the problem!
>>
>
> Interesting - I think it only used to work for the //noinspection version. 
> I guess we should make it a bit more flexible.
>
>
>> Sorry about the long email!
>>
>
> No problem, thanks for the feedback.
>
> -- Tor 
>

-- 
You received this message because you are subscribed to the Google Groups 
"adt-dev" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to [email protected].
For more options, visit https://groups.google.com/d/optout.

Reply via email to