Handle multiple arguments in thenThrow.

PiperOrigin-RevId: 738343494

Author: graememorgan

core/src/main/java/com/google/errorprone/bugpatterns/MockIllegalThrows.java

@@ -52,43 +52,46 @@ public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState
     if (!THEN_THROW.matches(tree, state)) {
       return NO_MATCH;
     }
-    ExpressionTree exceptionTree = tree.getArguments().get(0);
-    var thrownType = getType(exceptionTree);
-    if (!isCheckedExceptionType(thrownType, state)) {
-      return NO_MATCH;
-    }
-    // Heuristic: if the type being thrown is Exception/Throwable, but doesn't come directly from a
-    // constructor, it might be a parameter, and we can't know that it's not always given sensible
-    // types.
-    if (!(exceptionTree instanceof NewClassTree)
-        && (isSameType(thrownType, state.getSymtab().exceptionType, state)
-            || isSameType(thrownType, state.getSymtab().throwableType, state))) {
-      return NO_MATCH;
-    }
-    for (var receiver = getReceiver(tree);
-        receiver instanceof MethodInvocationTree whenMit;
-        receiver = getReceiver(receiver)) {
-      if (WHEN.matches(receiver, state)
-          && whenMit.getArguments().get(0) instanceof MethodInvocationTree mit
-          && getType(mit.getMethodSelect()).getThrownTypes().stream()
-              .noneMatch(
-                  throwableType -> state.getTypes().isAssignable(thrownType, throwableType))) {
-        var thrownTypes = getType(mit.getMethodSelect()).getThrownTypes();
-        return buildDescription(whenMit.getArguments().get(0))
-            .setMessage(
-                thrownTypes.isEmpty()
-                    ? format(
-                        "%s is not throwable by this method; only unchecked exceptions can be"
-                            + " thrown.",
-                        thrownType.tsym.getSimpleName())
-                    : format(
-                        "%s is not throwable by this method; possible exception types are %s, or"
-                            + " any unchecked exception.",
-                        thrownType.tsym.getSimpleName(),
-                        thrownTypes.stream()
-                            .map(t -> t.tsym.getSimpleName().toString())
-                            .collect(joining(", "))))
-            .build();
+    for (ExpressionTree exceptionTree : tree.getArguments()) {
+      var thrownType = getType(exceptionTree);
+      if (!isCheckedExceptionType(thrownType, state)) {
+        continue;
+      }
+      // Heuristic: if the type being thrown is Exception/Throwable, but doesn't come directly from
+      // a constructor, it might be a parameter, and we can't know that it's not always given
+      // sensible types.
+      if (!(exceptionTree instanceof NewClassTree)
+          && (isSameType(thrownType, state.getSymtab().exceptionType, state)
+              || isSameType(thrownType, state.getSymtab().throwableType, state))) {
+        continue;
+      }
+      for (var receiver = getReceiver(tree);
+          receiver instanceof MethodInvocationTree whenMit;
+          receiver = getReceiver(receiver)) {
+        if (WHEN.matches(receiver, state)
+            && whenMit.getArguments().get(0) instanceof MethodInvocationTree mit
+            && getType(mit.getMethodSelect()).getThrownTypes().stream()
+                .noneMatch(
+                    throwableType -> state.getTypes().isAssignable(thrownType, throwableType))) {
+          var thrownTypes = getType(mit.getMethodSelect()).getThrownTypes();
+          state.reportMatch(
+              buildDescription(whenMit.getArguments().get(0))
+                  .setMessage(
+                      thrownTypes.isEmpty()
+                          ? format(
+                              "%s is not throwable by this method; only unchecked exceptions can be"
+                                  + " thrown.",
+                              thrownType.tsym.getSimpleName())
+                          : format(
+                              "%s is not throwable by this method; possible exception types are %s,"
+                                  + " or any unchecked exception.",
+                              thrownType.tsym.getSimpleName(),
+                              thrownTypes.stream()
+                                  .map(t -> t.tsym.getSimpleName().toString())
+                                  .collect(joining(", "))))
+                  .build());
+          break;
+        }
       }
     }
     return NO_MATCH;

core/src/test/java/com/google/errorprone/bugpatterns/MockIllegalThrowsTest.java

@@ -46,6 +46,26 @@ void test(Test t) {
         .doTest();
   }
 
+  @Test
+  public void positive_multipleThrows() {
+    compilationHelper
+        .addSourceLines(
+            "Test.java",
+            """
+            import static org.mockito.Mockito.when;
+
+            abstract class Test {
+              abstract Object foo();
+
+              void test(Test t) {
+                // BUG: Diagnostic contains: only unchecked
+                when(t.foo()).thenThrow(new IllegalStateException(), new Exception());
+              }
+            }
+            """)
+        .doTest();
+  }
+
   @Test
   public void positiveWithSpecificType() {
     compilationHelper
@@ -108,6 +128,25 @@ void test(Test t) throws Exception {
         .doTest();
   }
 
+  @Test
+  public void nothingThrown_noFinding() {
+    compilationHelper
+        .addSourceLines(
+            "Test.java",
+            """
+            import static org.mockito.Mockito.when;
+
+            abstract class Test {
+              abstract Object foo() throws Exception;
+
+              void test(Test t) throws Exception {
+                when(t.foo()).thenThrow();
+              }
+            }
+            """)
+        .doTest();
+  }
+
   @Test
   public void genericException() {
     compilationHelper