ANS-1289 Prefer flatMapIterable(identity()) over `flatMap(i -> Flux…

….fromIterable(i))`
PicnicSupermarket · Oct 5, 2022 · 6cf3c93 · 6cf3c93
1 parent 9ad8c27
commit 6cf3c93
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diff --git a/...rone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ReactorTemplates.java b/...rone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ReactorTemplates.java
@@ -2,6 +2,7 @@
 
 import static com.google.common.collect.MoreCollectors.toOptional;
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
+import static java.util.function.Function.identity;
 import static org.assertj.core.api.Assertions.assertThat;
 
 import com.google.common.collect.MoreCollectors;
@@ -271,6 +272,23 @@ Flux<S> after(Flux<T> flux) {
     }
   }
 
+  /**
+   * Prefer {@link Flux#flatMapIterable(Function)} (Class)} over {@link Flux#flatMap(Function)} with
+   * {@link Flux#fromIterable(Iterable)}.
+   */
+  static final class FluxFlatMapIterable<S> {
+    @BeforeTemplate
+    Flux<S> before(Flux<? extends Iterable<S>> flux) {
+      return flux.flatMap(list -> Flux.fromIterable(list));
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    Flux<S> after(Flux<? extends Iterable<S>> flux) {
+      return flux.flatMapIterable(identity());
+    }
+  }
+
   /** Prefer {@link PublisherProbe#empty()}} over more verbose alternatives. */
   static final class PublisherProbeEmpty<T> {
     @BeforeTemplate

diff --git a/...rc/test/resources/tech/picnic/errorprone/refastertemplates/ReactorTemplatesTestInput.java b/...rc/test/resources/tech/picnic/errorprone/refastertemplates/ReactorTemplatesTestInput.java
@@ -95,6 +95,10 @@ Flux<Number> testFluxCast() {
     return Flux.just(1).map(Number.class::cast);
   }
 
+  Flux<String> testFluxFlatMapIterable() {
+    return Flux.just(ImmutableList.of("1")).flatMap(list -> Flux.fromIterable(list));
+  }
+
   ImmutableSet<PublisherProbe<Void>> testPublisherProbeEmpty() {
     return ImmutableSet.of(PublisherProbe.of(Mono.empty()), PublisherProbe.of(Flux.empty()));
   }

diff --git a/...c/test/resources/tech/picnic/errorprone/refastertemplates/ReactorTemplatesTestOutput.java b/...c/test/resources/tech/picnic/errorprone/refastertemplates/ReactorTemplatesTestOutput.java
@@ -1,6 +1,7 @@
 package tech.picnic.errorprone.refastertemplates;
 
 import static com.google.common.collect.MoreCollectors.toOptional;
+import static java.util.function.Function.identity;
 import static org.assertj.core.api.Assertions.assertThat;
 
 import com.google.common.collect.ImmutableList;
@@ -94,6 +95,10 @@ Flux<Number> testFluxCast() {
     return Flux.just(1).cast(Number.class);
   }
 
+  Flux<String> testFluxFlatMapIterable() {
+    return Flux.just(ImmutableList.of("1")).flatMapIterable(identity());
+  }
+
   ImmutableSet<PublisherProbe<Void>> testPublisherProbeEmpty() {
     return ImmutableSet.of(PublisherProbe.empty(), PublisherProbe.empty());
   }