Would it be possible to detect side effects in addition to the annotation? Watching for interaction with anything with a greater scope than the method (such as a field). I would be much more likely to use this if I didn't have to remember to add the annotation to every method with a side effect.

My main android module build file have set java version = 1.7

  compileOptions {
    encoding "UTF-8"
    sourceCompatibility JavaVersion.VERSION_1_7
    targetCompatibility JavaVersion.VERSION_1_7
  }

Here is the error message when ran the app.

Error:Error converting bytecode to dex:
Cause: Dex cannot parse version 52 byte code.
This is caused by library dependencies that have been compiled using Java 8 or above.
If you are using the 'java' gradle plugin in a library submodule add 
targetCompatibility = '1.7'
sourceCompatibility = '1.7'
to that submodule's build.gradle file.
...while parsing com/anupcowkur/herebedragons/SideEffect.class

This makes it easy to find @sideeffect

In this line

This helsp you visually identify which methods are impure when a bunch of methods are being called in a code block

It should be helps.

Please correct it.

.

Let me start by saying, the name you've come up with for this library is awesome, I'm very tempted to steal it to make my own variation.
That being said, I figured I'd run my proposal by you before performing grand theft (please understand this is meant as a compliment, not a threat).

I'd like to be able to annotate the parameters on methods if the parameters get side effected.
For example:

/**
 * Allow us to annotate that collection passed has elements added/removed/sorted/ect...
 * within the method.
 */
int doActions(@SideEffectModifies(type = COLLECTION) final Set<Something> somethings) {
    somethings.add(anotherSomething());
    return somethings.size();
}

/**
 * Allow us to annotate that collection elements get modified when passed to the method.
 */
int doActions(@SideEffectModifies(type = ELEMENTS) final Set<Something> somethings) {
    something.forEach(something -> something.setIt("it"));
    return somethings.size();
}

/**
 * Allow us to annotate that both kinds of side effecting happens.
 */
int doActions(@SideEffectModifies(type = BOTH) final Set<Something> somethings) {
    somethings.add(anotherSomething());
    something.forEach(something -> something.setIt("it"));
    return somethings.size();
}

My particular use case is that I'm refactoring a large swath of code. I'd like myself and other developers to leave hints to each other that we have discovered this kind of side effecting behaviour. The goal is, while you might not be able to do the refactor to fix the problem at the time, you've figured out this is what is going on.

This is a neat little plugin, I can see it come in very helpful. I mainly develop in Kotlin though, so it would be great if I could also use it there - right now, I can annotate Kotlin code and it will show the dragon when called from Java code, but no dragons are shown in Kotlin code.

For instance, all methods in a Retrofit interface instance carry side-effects. Instead of marking every single method with a @SideEffect (which also clutters the method definitions in the class), I prefer marking the entire type instead.

This would also require another annotation to mark exclusions inside a class. Maybe another annotation named @Pure.

If one creates a tag of each release, from that point forward GitHub provides a way of attaching arbitrary release artifacts to that tag, moving the burden of hosting the artifacts onto GitHub and out of the repo itself.

One may do that manually, or GitHub also offers an API to create a release and then upload assets into it. One can create an api key suitable for housing in Travis or Circle or whatever, but the scope needs to be repo as I don't believe there is a scope specifically to "create a release."

GitHub also has helpful content which describes the overall picture