Add Resolver.getDeclarationsFromPackage() API for getting declaration…

…s with a given package name.

api/src/main/kotlin/com/google/devtools/ksp/processing/Resolver.kt

@@ -211,4 +211,13 @@ interface Resolver {
      */
     @KspExperimental
     fun getJvmCheckedException(function: KSFunctionDeclaration): Sequence<KSType>
+
+    /**
+     * Returns declarations with the given package name.
+     * @param packageName the package name to look up.
+     * @return A sequence of [KSDeclaration] with matching package name.
+     * This will return declarations from both dependencies and source.
+     */
+    @KspExperimental
+    fun getDeclarationsFromPackage(packageName: String): Sequence<KSDeclaration>
 }

compiler-plugin/src/main/kotlin/com/google/devtools/ksp/processing/impl/ResolverImpl.kt

@@ -41,6 +41,7 @@ import org.jetbrains.kotlin.container.ComponentProvider
 import org.jetbrains.kotlin.container.get
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.annotations.AnnotationDescriptor
+import org.jetbrains.kotlin.descriptors.impl.ModuleDescriptorImpl
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
 import org.jetbrains.kotlin.load.java.components.TypeUsage
 import org.jetbrains.kotlin.load.java.descriptors.JavaForKotlinOverridePropertyDescriptor
@@ -595,6 +596,15 @@ class ResolverImpl(
         }
     }
 
+    @KspExperimental
+    override fun getDeclarationsFromPackage(packageName: String): Sequence<KSDeclaration> {
+        module.getPackage(FqName(packageName)).memberScope
+        val res = (module as ModuleDescriptorImpl).packageFragmentProvider.packageFragments(FqName(packageName))
+            .flatMap{ it.getMemberScope().getContributedDescriptors() }
+            .mapNotNull { (it as? MemberDescriptor)?.toKSDeclaration() }
+        return res.asSequence()
+    }
+
     override fun getTypeArgument(typeRef: KSTypeReference, variance: Variance): KSTypeArgument {
         return KSTypeArgumentLiteImpl.getCached(typeRef, variance)
     }

compiler-plugin/src/main/kotlin/com/google/devtools/ksp/processor/GetPackageProcessor.kt

@@ -0,0 +1,29 @@
+package com.google.devtools.ksp.processor
+
+import com.google.devtools.ksp.KspExperimental
+import com.google.devtools.ksp.processing.Resolver
+import com.google.devtools.ksp.symbol.KSAnnotated
+
+class GetPackageProcessor : AbstractTestProcessor() {
+    val results = mutableListOf<String>()
+
+    override fun toResult(): List<String> {
+        return results
+    }
+
+    @KspExperimental
+    override fun process(resolver: Resolver): List<KSAnnotated> {
+        addPackage("lib1", resolver)
+        addPackage("lib2", resolver)
+        addPackage("main", resolver)
+        return emptyList()
+    }
+
+    @KspExperimental
+    private fun addPackage(name: String, resolver: Resolver) {
+        results.add("symbols from package $name")
+        resolver.getDeclarationsFromPackage(name).forEach {
+            results.add("${it.qualifiedName?.asString() ?: "error"} ${it.origin}")
+        }
+    }
+}

compiler-plugin/src/test/java/com/google/devtools/ksp/test/KotlinKSPTestGenerated.java

@@ -127,6 +127,11 @@ public void testFunctionTypeAlias() throws Exception {
         runTest("testData/api/functionTypeAlias.kt");
     }
 
+    @TestMetadata("getPackage.kt")
+    public void testGetPackage() throws Exception {
+        runTest("testData/api/getPackage.kt");
+    }
+
     @TestMetadata("getSymbolsFromAnnotation.kt")
     public void testGetSymbolsFromAnnotation() throws Exception {
         runTest("testData/api/getSymbolsFromAnnotation.kt");

compiler-plugin/testData/api/getPackage.kt

@@ -0,0 +1,69 @@
+/*
+ * Copyright 2021 Google LLC
+ * Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// TEST PROCESSOR: GetPackageProcessor
+// EXPECTED:
+// symbols from package lib1
+// lib1.FooInSource KOTLIN
+// lib1.propInSource KOTLIN
+// lib1.Bar CLASS
+// lib1.Foo CLASS
+// lib1.funcFoo CLASS
+// symbols from package lib2
+// lib2.Foo CLASS
+// lib2.a CLASS
+// symbols from package main
+// main.KotlinMain KOTLIN
+// END
+
+// MODULE: lib1
+// FILE: foo.kt
+package lib1
+
+class Foo
+
+fun funcFoo(): Int {
+    return 1
+}
+
+// FILE: Bar.java
+package lib1;
+
+class Bar {}
+
+// MODULE: lib2
+// FILE: foo.kt
+package lib2
+
+class Foo
+
+val a = 0
+
+// FILE: Bar.java
+
+class Bar {}
+
+// MODULE: main(lib1, lib2)
+// FILE: a.kt
+package lib1
+class FooInSource
+
+val propInSource = 1
+// FILE: main.kt
+package main
+
+class KotlinMain