3 files changed, 9 insertions, 1 deletions
diff --git a/absl/log/scoped_mock_log.cc b/absl/log/scoped_mock_log.cc
index 4ebc0a9f..39a0a52a 100644
--- a/absl/log/scoped_mock_log.cc
+++ b/absl/log/scoped_mock_log.cc
@@ -30,7 +30,7 @@ namespace absl {
 ABSL_NAMESPACE_BEGIN
 
 ScopedMockLog::ScopedMockLog(MockLogDefault default_exp)
-    : sink_(this), is_capturing_logs_(false) {
+    : sink_(this), is_capturing_logs_(false), is_triggered_(false) {
   if (default_exp == MockLogDefault::kIgnoreUnexpected) {
     // Ignore all calls to Log we did not set expectations for.
     EXPECT_CALL(*this, Log).Times(::testing::AnyNumber());
diff --git a/absl/log/scoped_mock_log.h b/absl/log/scoped_mock_log.h
index 44470c16..399e604d 100644
--- a/absl/log/scoped_mock_log.h
+++ b/absl/log/scoped_mock_log.h
@@ -185,6 +185,9 @@ class ScopedMockLog final {
 
   ForwardingSink sink_;
   bool is_capturing_logs_;
+  // Until C++20, the default constructor leaves the underlying value wrapped in
+  // std::atomic uninitialized, so all constructors should be sure to initialize
+  // is_triggered_.
   std::atomic<bool> is_triggered_;
 };
 
diff --git a/absl/log/scoped_mock_log_test.cc b/absl/log/scoped_mock_log_test.cc
index 44b8d737..42736939 100644
--- a/absl/log/scoped_mock_log_test.cc
+++ b/absl/log/scoped_mock_log_test.cc
@@ -71,6 +71,11 @@ TEST(ScopedMockLogDeathTest, StopCapturingLogsCannotBeCalledWhenNotCapturing) {
       },
       "StopCapturingLogs");
 }
+
+TEST(ScopedMockLogDeathTest, FailsCheckIfStartCapturingLogsIsNeverCalled) {
+  EXPECT_DEATH({ absl::ScopedMockLog log; },
+               "Did you forget to call StartCapturingLogs");
+}
 #endif
 
 // Tests that ScopedMockLog intercepts LOG()s when it's alive.