Extend StreamIsEmpty Refaster rule (#1025)

PicnicSupermarket · Feb 11, 2024 · 1f71ccc · 1f71ccc
1 parent 57fa6ae
commit 1f71ccc
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Showing 3 changed files with 48 additions and 7 deletions.
diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/StreamRules.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/StreamRules.java
@@ -4,6 +4,7 @@
 import static java.util.Comparator.naturalOrder;
 import static java.util.Comparator.reverseOrder;
 import static java.util.function.Predicate.not;
+import static java.util.stream.Collectors.collectingAndThen;
 import static java.util.stream.Collectors.counting;
 import static java.util.stream.Collectors.filtering;
 import static java.util.stream.Collectors.flatMapping;
@@ -37,6 +38,7 @@
 import java.util.DoubleSummaryStatistics;
 import java.util.IntSummaryStatistics;
 import java.util.LongSummaryStatistics;
+import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.function.BinaryOperator;
@@ -254,15 +256,21 @@ Optional<S> after(Stream<T> stream, Function<? super T, S> function) {
   // XXX: This rule assumes that any matched `Collector` does not perform any filtering.
   // (Perhaps we could add a `@Matches` guard that validates that the collector expression does not
   // contain a `Collectors#filtering` call. That'd still not be 100% accurate, though.)
-  static final class StreamIsEmpty<T> {
+  static final class StreamIsEmpty<T, K, V, C extends Collection<K>, M extends Map<K, V>> {
     @BeforeTemplate
-    boolean before(Stream<T> stream, Collector<? super T, ?, ? extends Collection<?>> collector) {
+    boolean before(Stream<T> stream, Collector<? super T, ?, ? extends C> collector) {
       return Refaster.anyOf(
           stream.count() == 0,
           stream.count() <= 0,
           stream.count() < 1,
           stream.findFirst().isEmpty(),
-          stream.collect(collector).isEmpty());
+          stream.collect(collector).isEmpty(),
+          stream.collect(collectingAndThen(collector, C::isEmpty)));
+    }
+
+    @BeforeTemplate
+    boolean before2(Stream<T> stream, Collector<? super T, ?, ? extends M> collector) {
+      return stream.collect(collectingAndThen(collector, M::isEmpty));
     }
 
     @AfterTemplate

diff --git a/...contrib/src/test/resources/tech/picnic/errorprone/refasterrules/StreamRulesTestInput.java b/...contrib/src/test/resources/tech/picnic/errorprone/refasterrules/StreamRulesTestInput.java
@@ -1,10 +1,13 @@
 package tech.picnic.errorprone.refasterrules;
 
+import static com.google.common.collect.ImmutableList.toImmutableList;
+import static com.google.common.collect.ImmutableMap.toImmutableMap;
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static java.util.Comparator.comparingInt;
 import static java.util.Comparator.reverseOrder;
 import static java.util.function.Function.identity;
 import static java.util.function.Predicate.not;
+import static java.util.stream.Collectors.collectingAndThen;
 import static java.util.stream.Collectors.counting;
 import static java.util.stream.Collectors.filtering;
 import static java.util.stream.Collectors.flatMapping;
@@ -21,11 +24,14 @@
 import static java.util.stream.Collectors.summingLong;
 
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Streams;
 import java.util.DoubleSummaryStatistics;
 import java.util.IntSummaryStatistics;
+import java.util.List;
 import java.util.LongSummaryStatistics;
+import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.function.Function;
@@ -38,8 +44,12 @@ final class StreamRulesTest implements RefasterRuleCollectionTestCase {
   public ImmutableSet<Object> elidedTypesAndStaticImports() {
     return ImmutableSet.of(
         ImmutableList.class,
+        ImmutableMap.class,
+        List.class,
+        Map.class,
         Objects.class,
         Streams.class,
+        collectingAndThen(null, null),
         counting(),
         filtering(null, null),
         flatMapping(null, null),
@@ -54,7 +64,9 @@ public ImmutableSet<Object> elidedTypesAndStaticImports() {
         summarizingLong(null),
         summingDouble(null),
         summingInt(null),
-        summingLong(null));
+        summingLong(null),
+        toImmutableList(),
+        toImmutableMap(null, null));
   }
 
   String testJoining() {
@@ -114,7 +126,12 @@ ImmutableSet<Boolean> testStreamIsEmpty() {
         Stream.of(2).count() <= 0,
         Stream.of(3).count() < 1,
         Stream.of(4).findFirst().isEmpty(),
-        Stream.of(5).collect(toImmutableSet()).isEmpty());
+        Stream.of(5).collect(toImmutableSet()).isEmpty(),
+        Stream.of(6).collect(collectingAndThen(toImmutableList(), List::isEmpty)),
+        Stream.of(7).collect(collectingAndThen(toImmutableList(), ImmutableList::isEmpty)),
+        Stream.of(8).collect(collectingAndThen(toImmutableMap(k -> k, v -> v), Map::isEmpty)),
+        Stream.of(9)
+            .collect(collectingAndThen(toImmutableMap(k -> k, v -> v), ImmutableMap::isEmpty)));
   }
 
   ImmutableSet<Boolean> testStreamIsNotEmpty() {

diff --git a/...ontrib/src/test/resources/tech/picnic/errorprone/refasterrules/StreamRulesTestOutput.java b/...ontrib/src/test/resources/tech/picnic/errorprone/refasterrules/StreamRulesTestOutput.java
@@ -1,11 +1,14 @@
 package tech.picnic.errorprone.refasterrules;
 
+import static com.google.common.collect.ImmutableList.toImmutableList;
+import static com.google.common.collect.ImmutableMap.toImmutableMap;
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static java.util.Comparator.comparingInt;
 import static java.util.Comparator.naturalOrder;
 import static java.util.Comparator.reverseOrder;
 import static java.util.function.Function.identity;
 import static java.util.function.Predicate.not;
+import static java.util.stream.Collectors.collectingAndThen;
 import static java.util.stream.Collectors.counting;
 import static java.util.stream.Collectors.filtering;
 import static java.util.stream.Collectors.flatMapping;
@@ -22,12 +25,15 @@
 import static java.util.stream.Collectors.summingLong;
 
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Streams;
 import java.util.Arrays;
 import java.util.DoubleSummaryStatistics;
 import java.util.IntSummaryStatistics;
+import java.util.List;
 import java.util.LongSummaryStatistics;
+import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.function.Function;
@@ -40,8 +46,12 @@ final class StreamRulesTest implements RefasterRuleCollectionTestCase {
   public ImmutableSet<Object> elidedTypesAndStaticImports() {
     return ImmutableSet.of(
         ImmutableList.class,
+        ImmutableMap.class,
+        List.class,
+        Map.class,
         Objects.class,
         Streams.class,
+        collectingAndThen(null, null),
         counting(),
         filtering(null, null),
         flatMapping(null, null),
@@ -56,7 +66,9 @@ public ImmutableSet<Object> elidedTypesAndStaticImports() {
         summarizingLong(null),
         summingDouble(null),
         summingInt(null),
-        summingLong(null));
+        summingLong(null),
+        toImmutableList(),
+        toImmutableMap(null, null));
   }
 
   String testJoining() {
@@ -115,7 +127,11 @@ ImmutableSet<Boolean> testStreamIsEmpty() {
         Stream.of(2).findAny().isEmpty(),
         Stream.of(3).findAny().isEmpty(),
         Stream.of(4).findAny().isEmpty(),
-        Stream.of(5).findAny().isEmpty());
+        Stream.of(5).findAny().isEmpty(),
+        Stream.of(6).findAny().isEmpty(),
+        Stream.of(7).findAny().isEmpty(),
+        Stream.of(8).findAny().isEmpty(),
+        Stream.of(9).findAny().isEmpty());
   }
 
   ImmutableSet<Boolean> testStreamIsNotEmpty() {