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package org.pkl.thirdparty.truffle.api.dsl;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import org.pkl.thirdparty.truffle.api.Assumption;
import org.pkl.thirdparty.truffle.api.ContextLocal;
import org.pkl.thirdparty.truffle.api.ContextThreadLocal;
import org.pkl.thirdparty.truffle.api.TruffleLanguage.ContextPolicy;
import org.pkl.thirdparty.truffle.api.TruffleLanguage.LanguageReference;
import org.pkl.thirdparty.truffle.api.nodes.DirectCallNode;
import org.pkl.thirdparty.truffle.api.nodes.Node;
/**
* Methods annotated with {@link Idempotent} must be methods that may cause side effects but will
* always cause the same side effects for repeated invocations with the same parameters. From this
* follows that an idempotent method must return the same result after it was executed once for each
* consecutive execution given the same parameters.
*
* Truffle DSL uses this property to execute {@link Specialization#guards() guards} where all bound
* methods are idempotent once on the slow-path, during specialization, and never on the fast-path.
* By default, all methods that do not bind dynamic parameters are interpreted as idempotent for
* compatibility reasons. The DSL emits warnings whenever a method should be annotated either with
* {@link Idempotent} or {@link NonIdempotent}. Note that guards that bind dynamic parameters will
* never be idempotent in the fast-path, so the DSL will not require annotations for such guards.
*
*
* Examples for non-idempotent methods are:
*
* - {@link ContextThreadLocal#get()}
*
- {@link Assumption#isValid()}
*
- {@link Assumption#isValidAssumption(Assumption)}
*
- {@link Assumption#isValidAssumption(Assumption[])}
*
- {@link ContextLocal#get()} if the language uses a context policy {@link ContextPolicy#REUSE}
* or {@link ContextPolicy#SHARED}
*
*
* Examples for idempotent methods are:
*
* - {@link LanguageReference#get(Node)}
*
- {@link DirectCallNode#getCallTarget()}
*
- {@link ContextLocal#get()} if the language uses context policy
* {@link ContextPolicy#EXCLUSIVE}.
*
*
* Note that usages may assume that the current language instance never changes for a given Node.
* Therefore it is safe to assume language reference accesses idempotent.
*
* @see NonIdempotent
* @since 23.0
*/
@Retention(RetentionPolicy.CLASS)
@Target({ElementType.METHOD})
public @interface Idempotent {
}