From f9b80d9beef469f3ed9fcbba77fdcdbabdbd12d0 Mon Sep 17 00:00:00 2001
From: Uwe Schindler <uwe@thetaphi.de>
Date: Wed, 2 Sep 2020 12:30:03 +0200
Subject: [PATCH] Add better reporting if ASM fails to parse a class with an
 unspecified RuntimeException

---
 .../de/thetaphi/forbiddenapis/AsmUtils.java   |  9 ++++++++
 .../de/thetaphi/forbiddenapis/Checker.java    | 22 ++++++++++++++++++-
 .../RelatedClassLoadingException.java         |  5 +++++
 3 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/src/main/java/de/thetaphi/forbiddenapis/AsmUtils.java b/src/main/java/de/thetaphi/forbiddenapis/AsmUtils.java
index e7f0fb79..2aeaeb02 100644
--- a/src/main/java/de/thetaphi/forbiddenapis/AsmUtils.java
+++ b/src/main/java/de/thetaphi/forbiddenapis/AsmUtils.java
@@ -24,6 +24,7 @@
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.util.Locale;
+import java.util.Objects;
 import java.util.regex.Pattern;
 
 import org.objectweb.asm.ClassReader;
@@ -181,5 +182,13 @@ public static ClassReader readAndPatchClass(InputStream in) throws IOException {
     if (false) patchClassMajorVersion(bytecode, Opcodes.V15 + 1, Opcodes.V15);
     return new ClassReader(bytecode);
   }
+  
+  /** Returns true, if the given {@link RuntimeException} was caused by ASM's ClassReader */
+  public static boolean isExceptionInAsmClassReader(RuntimeException re) {
+    // Because of javac bugs some class files are broken and cause RuntimeExceptions like AIOOBE
+    // We analyze stack trace if this is caused by ASM's ClassReader and not our code:
+    final StackTraceElement[] stack = re.getStackTrace();
+    return stack.length > 0 && Objects.equals(ClassReader.class.getName(), stack[0].getClassName());
+  }
 
 }
diff --git a/src/main/java/de/thetaphi/forbiddenapis/Checker.java b/src/main/java/de/thetaphi/forbiddenapis/Checker.java
index 3f236224..a2633d17 100644
--- a/src/main/java/de/thetaphi/forbiddenapis/Checker.java
+++ b/src/main/java/de/thetaphi/forbiddenapis/Checker.java
@@ -309,6 +309,11 @@ public ClassSignature lookupRelatedClass(String internalName, String internalNam
       }
     } catch (IOException ioe) {
       throw new RelatedClassLoadingException(ioe, Type.getObjectType(internalNameOrig).getClassName());
+    } catch (RuntimeException re) {
+      if (AsmUtils.isExceptionInAsmClassReader(re)) {
+        throw new RelatedClassLoadingException(re, Type.getObjectType(internalNameOrig).getClassName());
+      }
+      throw re;
     }
   }
   
@@ -419,8 +424,23 @@ private int checkClass(final ClassReader reader, Pattern suppressAnnotationsPatt
       }
       msg.append(": ").append(cause);
       msg.append(" (while looking up details about referenced class '").append(rcle.getClassName()).append("')");
-      assert cause != null && (cause instanceof IOException || cause instanceof ClassNotFoundException);
+      assert cause != null && (cause instanceof IOException || cause instanceof ClassNotFoundException || cause instanceof RuntimeException);
       throw new ForbiddenApiException(msg.toString(), cause);
+    } catch (RuntimeException re) {
+      if (AsmUtils.isExceptionInAsmClassReader(re)) {
+        final StringBuilder msg = new StringBuilder()
+            .append("Failed to parse class '")
+            .append(className)
+            .append('\'');
+        final String source = scanner.getSourceFile();
+        if (source != null) {
+          msg.append(" (").append(source).append(')');
+        }
+        msg.append(": ").append(re);
+        throw new ForbiddenApiException(msg.toString(), re);
+      }
+      // else rethrow (it's occuring in our code):
+      throw re;
     }
     final List<ForbiddenViolation> violations = scanner.getSortedViolations();
     final Pattern splitter = Pattern.compile(Pattern.quote(ForbiddenViolation.SEPARATOR));
diff --git a/src/main/java/de/thetaphi/forbiddenapis/RelatedClassLoadingException.java b/src/main/java/de/thetaphi/forbiddenapis/RelatedClassLoadingException.java
index ffe1eb98..4a1cf660 100644
--- a/src/main/java/de/thetaphi/forbiddenapis/RelatedClassLoadingException.java
+++ b/src/main/java/de/thetaphi/forbiddenapis/RelatedClassLoadingException.java
@@ -33,6 +33,11 @@ public RelatedClassLoadingException(IOException e, String className) {
     this.className = className;
   }
   
+  public RelatedClassLoadingException(RuntimeException e, String className) {
+    super(e);
+    this.className = className;
+  }
+  
   public Exception getException() {
     return (Exception) getCause();
   }