Relax the assertion in Desugar for checking the calls to $closeResource(...).

It is possible that $closeResource(...) is not used as the calls to it might
be eliminated by some optimization tools, such as Proguard.

RELNOTES: n/a.
PiperOrigin-RevId: 193262552
GitOrigin-RevId: 1a2ab6d54e2a8749549f41055cd66f3f6dfea4cc
Change-Id: Ifdbd7b47132b541ecfd831d2a7b83d76853ec206

3 files changed, 13 insertions, 7 deletions

diff --git a/java/com/google/devtools/build/android/desugar/TryWithResourcesRewriter.java b/java/com/google/devtools/build/android/desugar/TryWithResourcesRewriter.java
index 818585f..98eef45 100644
--- a/java/com/google/devtools/build/android/desugar/TryWithResourcesRewriter.java
+++ b/java/com/google/devtools/build/android/desugar/TryWithResourcesRewriter.java
@@ -166,14 +166,12 @@ public class TryWithResourcesRewriter extends ClassVisitor {
             new CloseResourceMethodSpecializer(cv, resourceInternalName, isInterface));
       }
     } else {
+      // It is possible that all calls to $closeResources(...) are in dead code regions, and the
+      // calls are eliminated, which leaving the method $closeResources() unused. (b/78030676).
+      // In this case, we just discard the method body.
       checkState(
-          closeResourceMethod == null,
-          "The field resourceTypeInternalNames is empty. "
-              + "But the class has the $closeResource method.");
-      checkState(
-          !hasCloseResourceMethod,
-          "The class %s has close resource method, but resourceTypeInternalNames is empty.",
-          internalName);
+          !hasCloseResourceMethod || closeResourceMethod != null,
+          "There should be $closeResources(...) in the class file.");
     }
     super.visitEnd();
   }
diff --git a/test/java/com/google/devtools/build/android/desugar/desugar_unused_synthetic_close_resource_method_golden.txt b/test/java/com/google/devtools/build/android/desugar/desugar_unused_synthetic_close_resource_method_golden.txt
new file mode 100644
index 0000000..4be60b6
--- /dev/null
+++ b/test/java/com/google/devtools/build/android/desugar/desugar_unused_synthetic_close_resource_method_golden.txt
@@ -0,0 +1,8 @@
+Compiled from "UnusedSyntheticCloseResourceMethod.java"
+public class com.google.devtools.build.android.desugar.testdata.UnusedSyntheticCloseResourceMethod {
+  public com.google.devtools.build.android.desugar.testdata.UnusedSyntheticCloseResourceMethod();
+    Code:
+       0: aload_0
+       1: invokespecial #9                  // Method java/lang/Object."<init>":()V
+       4: return
+}
diff --git a/test/java/com/google/devtools/build/android/desugar/unused_closed_resource.jar b/test/java/com/google/devtools/build/android/desugar/unused_closed_resource.jar
new file mode 100644
index 0000000..6a451eb
--- /dev/null
+++ b/test/java/com/google/devtools/build/android/desugar/unused_closed_resource.jar