Stream inlining: more precise source/terminal handling

Fixes IDEA-176129 Provide Control flow related inspection for Stream.anyMatch() / Stream.allMatch() / Stream.noneMatch()
2026-08-26 03:13:40 +07:00 · 2017-08-14 17:27:36 +07:00
parent 152dad886c
commit 4a48b57906
4 changed files with 373 additions and 34 deletions
@@ -0,0 +1,124 @@
+import java.util.*;
+import java.util.stream.*;
+
+public class StreamKnownSource {
+  void testFlatMap(List<String> list) {
+    long count = list.stream().<String>flatMap(s -> Stream.empty()).count();
+    if(<warning descr="Condition 'count > 0' is always 'false'">count > 0</warning>) {
+      System.out.println("Impossible");
+    }
+  }
+
+  void testEmptyStream(List<String> list) {
+    long result = Stream.empty().count();
+
+    if (<warning descr="Condition 'result > 0' is always 'false'">result > 0</warning>) {
+      System.out.println("Never");
+    }
+
+    int sum = list.stream().filter(Objects::isNull).filter(<warning descr="Method reference result is always 'false'">Objects::nonNull</warning>).mapToInt(String::length).sum();
+    if (<warning descr="Condition 'sum == 0' is always 'true'">sum == 0</warning>) {
+      System.out.println("Always");
+    }
+
+    Optional<String> any = Stream.<String>empty().map(String::trim).findAny();
+    if (<warning descr="Condition 'any.isPresent()' is always 'false'">any.isPresent()</warning>) {
+      System.out.println("Never");
+    }
+    Optional<String> any2 = Stream.of("x").map(String::trim).findAny();
+    if (<warning descr="Condition 'any2.isPresent()' is always 'true'">any2.isPresent()</warning>) {
+      System.out.println("Always");
+    }
+    Optional<String> any3 = list.stream().map(String::trim).findAny();
+    if (any3.isPresent()) {
+      System.out.println("Possible");
+    }
+    Optional<String> any4 = Stream.of("x").limit(list.size()).map(String::trim).findAny();
+    if (any4.isPresent()) {
+      System.out.println("Probably");
+    }
+
+    boolean emptyAll = Stream.empty().allMatch(Objects::nonNull);
+    if (<warning descr="Condition 'emptyAll' is always 'true'">emptyAll</warning>) {
+      System.out.println("True");
+    }
+    boolean emptyAny = Stream.empty().anyMatch(Objects::nonNull);
+    if (<warning descr="Condition 'emptyAny' is always 'false'">emptyAny</warning>) {
+      System.out.println("False");
+    }
+    boolean emptyNone = Stream.empty().noneMatch(Objects::nonNull);
+    if (<warning descr="Condition 'emptyNone' is always 'true'">emptyNone</warning>) {
+      System.out.println("True");
+    }
+
+    boolean allMatch = Stream.generate(() -> "foo").limit(10).allMatch(<warning descr="Method reference result is always 'false'">"bar"::equals</warning>);
+    if (allMatch) { // currently we're not aware that stream is non-empty (limit arg is not processed), and allMatch could be true for empty list
+      System.out.println("Who knows?");
+    }
+    Optional<String> min = Stream.<String>empty().min(Comparator.comparing(String::length));
+    if(<warning descr="Condition 'min.isPresent()' is always 'false'">min.isPresent()</warning>) {
+      System.out.println("Impossible");
+    }
+  }
+
+  void testSingleElement(String foo) {
+    Optional<String> notNull = Stream.of(foo).filter(Objects::nonNull).findAny();
+    if(<warning descr="Condition 'notNull.isPresent() && foo == null' is always 'false'">notNull.isPresent() && <warning descr="Condition 'foo == null' is always 'false' when reached">foo == null</warning></warning>) {
+      System.out.println("Impossible");
+    }
+    OptionalInt max = IntStream.of(1).max();
+    if(<warning descr="Condition 'max.isPresent()' is always 'true'">max.isPresent()</warning>) {
+      System.out.println("Always");
+    }
+    OptionalLong opt = LongStream.of(2).reduce(Long::sum);
+    if(<warning descr="Condition 'opt.isPresent()' is always 'true'">opt.isPresent()</warning>) {
+      System.out.println("Always");
+    }
+  }
+
+  void testStreamOf(int[] arr) {
+    if(Stream.of().count() > 0) {
+      System.out.println("Impossible");
+    }
+    if(<warning descr="Condition 'Stream.of(\"foo\", \"bar\").findFirst().isPresent()' is always 'true'">Stream.of("foo", "bar").findFirst().isPresent()</warning>) {
+      System.out.println("Always");
+    }
+    if(<warning descr="Condition 'DoubleStream.of(0.0, 1.0, 2.0, 3.0).map(x -> x*2).max().isPresent()' is always 'true'">DoubleStream.of(0.0, 1.0, 2.0, 3.0).map(x -> x*2).max().isPresent()</warning>) {
+      System.out.println("Always");
+    }
+    if(<warning descr="Condition 'IntStream.of(arr).filter(x -> x > 0).sum() > 0 && arr.length == 0' is always 'false'">IntStream.of(arr).filter(x -> x > 0).sum() > 0 && <warning descr="Condition 'arr.length == 0' is always 'false' when reached">arr.length == 0</warning></warning>) {
+      System.out.println("Impossible");
+    }
+  }
+
+  void testListSize(List<String> list, int[] arr) {
+    if (<warning descr="Condition 'arr.length == 0 && Arrays.stream(arr).anyMatch(x -> x > 0)' is always 'false'">arr.length == 0 && <warning descr="Condition 'Arrays.stream(arr).anyMatch(x -> x > 0)' is always 'false' when reached">Arrays.stream(arr).anyMatch(x -> x > 0)</warning></warning>) {
+      System.out.println("Impossible");
+    }
+    if (<warning descr="Condition 'Arrays.stream(arr).anyMatch(x -> x > 0) && arr.length == 0' is always 'false'">Arrays.stream(arr).anyMatch(x -> x > 0) && <warning descr="Condition 'arr.length == 0' is always 'false' when reached">arr.length == 0</warning></warning>) {
+      System.out.println("Impossible");
+    }
+    boolean empty = list.isEmpty();
+    String res = list.stream().map(String::trim).findFirst().orElse(null);
+    if(res == null && <warning descr="Condition 'empty' is always 'true' when reached">empty</warning>) {
+      System.out.println("res == null -> empty list");
+    }
+    Optional<String> first = list.stream().filter(Objects::nonNull).findFirst();
+    if (empty) {
+      System.out.println(first.<warning descr="'Optional.get()' without 'isPresent()' check">get</warning>());
+    }
+  }
+
+  // IDEA-176129
+  void foo(List<Long> list) {
+    if (!list.isEmpty()) {
+      return;
+    }
+
+    boolean hasNoNulls = list.stream().allMatch(Objects::nonNull);
+
+    if(<warning descr="Condition 'hasNoNulls' is always 'true'">hasNoNulls</warning>) {
+      System.out.println("Always");
+    }
+  }
+}