Merge pull request #916 from sebright/enable-checker-framework

Run Checker Framework null analysis (fixes #359).

4 files changed, 23 insertions, 3 deletions

diff --git a/contrib/agent/src/main/java/io/opencensus/contrib/agent/bootstrap/ContextTrampoline.java b/contrib/agent/src/main/java/io/opencensus/contrib/agent/bootstrap/ContextTrampoline.java
index dd250790..382a161d 100644
--- a/contrib/agent/src/main/java/io/opencensus/contrib/agent/bootstrap/ContextTrampoline.java
+++ b/contrib/agent/src/main/java/io/opencensus/contrib/agent/bootstrap/ContextTrampoline.java
@@ -31,6 +31,8 @@ package io.opencensus.contrib.agent.bootstrap;
  * <p>{@code ContextTrampoline} is implemented as a static class to allow for easy and fast use from
  * instrumented bytecode. We cannot use dependency injection for the instrumented bytecode.
  */
+// TODO(sebright): Fix the Checker Framework warnings.
+@SuppressWarnings("nullness")
 public final class ContextTrampoline {
 
   // Not synchronized to avoid any synchronization costs after initialization.
diff --git a/contrib/agent/src/main/java/io/opencensus/contrib/agent/bootstrap/TraceTrampoline.java b/contrib/agent/src/main/java/io/opencensus/contrib/agent/bootstrap/TraceTrampoline.java
index 975caf99..b4501b45 100644
--- a/contrib/agent/src/main/java/io/opencensus/contrib/agent/bootstrap/TraceTrampoline.java
+++ b/contrib/agent/src/main/java/io/opencensus/contrib/agent/bootstrap/TraceTrampoline.java
@@ -35,6 +35,8 @@ import javax.annotation.Nullable;
  * <p>{@code TraceTrampoline} is implemented as a static class to allow for easy and fast use from
  * instrumented bytecode. We cannot use dependency injection for the instrumented bytecode.
  */
+// TODO(sebright): Fix the Checker Framework warnings.
+@SuppressWarnings("nullness")
 public final class TraceTrampoline {
 
   // Not synchronized to avoid any synchronization costs after initialization.
diff --git a/contrib/zpages/src/main/java/io/opencensus/contrib/zpages/TraceConfigzZPageHandler.java b/contrib/zpages/src/main/java/io/opencensus/contrib/zpages/TraceConfigzZPageHandler.java
index 9b075b30..5257960d 100644
--- a/contrib/zpages/src/main/java/io/opencensus/contrib/zpages/TraceConfigzZPageHandler.java
+++ b/contrib/zpages/src/main/java/io/opencensus/contrib/zpages/TraceConfigzZPageHandler.java
@@ -16,8 +16,6 @@
 
 package io.opencensus.contrib.zpages;
 
-import static com.google.common.base.Strings.isNullOrEmpty;
-
 import com.google.common.base.Charsets;
 import io.opencensus.trace.config.TraceConfig;
 import io.opencensus.trace.config.TraceParams;
@@ -27,6 +25,11 @@ import java.io.OutputStream;
 import java.io.OutputStreamWriter;
 import java.io.PrintWriter;
 import java.util.Map;
+import javax.annotation.Nullable;
+
+/*>>>
+import org.checkerframework.checker.nullness.qual.EnsuresNonNullIf;
+*/
 
 // TODO(bdrutu): Add tests.
 /**
@@ -167,6 +170,13 @@ final class TraceConfigzZPageHandler extends ZPageHandler {
     }
   }
 
+  // TODO(sebright): Try to use a Checker Framework stub file for the Guava Strings class and use
+  // Strings.isNullOrEmpty instead.
+  /*>>> @EnsuresNonNullIf(result = false, expression = "#1") */
+  private static boolean isNullOrEmpty(@Nullable String str) {
+    return str == null || str.isEmpty();
+  }
+
   // Prints a table to a PrintWriter that shows existing trace parameters.
   private static void emitTraceParamsTable(TraceParams params, PrintWriter out) {
     out.write(
diff --git a/contrib/zpages/src/main/java/io/opencensus/contrib/zpages/TracezZPageHandler.java b/contrib/zpages/src/main/java/io/opencensus/contrib/zpages/TracezZPageHandler.java
index a1f3545b..7a42c2c7 100644
--- a/contrib/zpages/src/main/java/io/opencensus/contrib/zpages/TracezZPageHandler.java
+++ b/contrib/zpages/src/main/java/io/opencensus/contrib/zpages/TracezZPageHandler.java
@@ -370,7 +370,7 @@ final class TracezZPageHandler extends ZPageHandler {
               .escape(
                   event.getEvent() instanceof Annotation
                       ? renderAnnotation((Annotation) event.getEvent())
-                      : renderNetworkEvents((NetworkEvent) event.getEvent())));
+                      : renderNetworkEvents((NetworkEvent) castNonNull(event.getEvent()))));
 
       lastTimestampNanos = event.getTimestamp();
     }
@@ -383,6 +383,12 @@ final class TracezZPageHandler extends ZPageHandler {
         "", htmlEscaper().escape(renderAttributes(span.getAttributes().getAttributeMap())));
   }
 
+  // TODO(sebright): Remove this method.
+  @SuppressWarnings("nullness")
+  private static <T> T castNonNull(@Nullable T arg) {
+    return arg;
+  }
+
   // Emits the summary table with links to all samples.
   private void emitSummaryTable(PrintWriter out, Formatter formatter)
       throws UnsupportedEncodingException {