Tighten assumptions around CAD3 vs. CVM values

Author: mikera

convex-core/src/main/java/convex/core/cpos/Block.java

@@ -214,11 +214,6 @@ public boolean equals(Block a) {
 		if (!(Cells.equals(transactions, a.transactions))) return false;
 		return true;
 	}
-	
-	@Override
-	public boolean isCVMValue() {
-		return false;
-	}
 
 	@Override
 	public int getRefCount() {

convex-core/src/main/java/convex/core/cpos/Order.java

@@ -159,12 +159,6 @@ public static Order read(Blob b, int pos) throws BadFormatException {
 		result.attachEncoding(b.slice(pos, epos));
 		return result;
 	}
-	
-
-	@Override public final boolean isCVMValue() {
-		// Orders exist outside CVM only
-		return false;
-	}
 
 	/**
 	 * Checks if another Order is consistent with this Order.

convex-core/src/main/java/convex/core/cvm/Receipt.java

@@ -89,11 +89,6 @@ public byte getTag() {
 		int tag=Tag.RECEIPT+(isError?Tag.RECEIPT_ERROR_MASK:0)+((log==null)?0:Tag.RECEIPT_LOG_MASK);
 		return (byte)tag;
 	}
-	
-	@Override public final boolean isCVMValue() {
-		// Receipts exist outside CVM only
-		return false;
-	}
 
 	@Override
 	public RecordFormat getFormat() {

convex-core/src/main/java/convex/core/data/ACell.java

@@ -8,9 +8,9 @@
 import convex.core.util.Utils;
 
 /**
- * Abstract base class for Cells.
+ * Abstract base class for Cells in CAD3 data format.
  * 
- * Cells may contain Refs to other Cells, which can be tested with getRefCount()
+ * Cells may contain Refs to 0-63 child Cells, which can be tested with getRefCount()
  * 
  * All data objects intended for on-chain usage / serialisation should extend this. 
  * 
@@ -348,25 +348,24 @@ public boolean isEmbedded() {
 	public abstract boolean isCanonical();
 
 	/**
-	 * Converts this Cell to a canonical version. Must return this Cell if already canonical, may be O(n) in size of value otherwise.
+	 * Converts this Cell to a canonical version, if not already canonical.
 	 * 
-	 * Callers should usually use getCanonical(), which caches canonical instances once created 
+	 * Must return this Cell if already canonical, may be O(n) in size of value otherwise.
+	 * 
+	 * Users should usually use getCanonical(), which caches canonical instances once created 
 	 * 
 	 * @return Canonical version of Cell
 	 */
 	protected abstract ACell toCanonical();
 
 	/**
-	 * Returns true if this cell is a first class CVM Value used in the CVM state
-	 * 
-	 * Sub-structural cells that are not themselves first class values
-	 * should return false
+	 * Returns true if this cell is a first class CVM Value.
 	 * 
-	 * Records and types that are not permissible on the CVM should return false.
+	 * CAD3 Records and types that are not recognised by the CVM must return false.
 	 * 
-	 * Pretty much everything else should return true.
+	 * Everything the CVM can recognise must return true.
 	 * 
-	 * Note: CVM values might not be in a canonical format, e.g. temporary data structures
+	 * Note: CVM values might still not be in a canonical format, e.g. temporary data structures
 	 * 
 	 * @return true if the object is a CVM Value, false otherwise
 	 */

convex-core/src/main/java/convex/core/data/ARecord.java

@@ -13,7 +13,7 @@
 import convex.core.lang.RecordFormat;
 
 /**
- * Base class for Record data types. 
+ * Base class for CVM Record data types. 
  * 
  * Records are Map-like data structures with fixed sets of Keyword keys, and optional custom behaviour.
  * 
@@ -50,7 +50,7 @@ protected ARecord toCanonical() {
 		return this;
 	}
 
-	@Override public boolean isCVMValue() {
+	@Override final public boolean isCVMValue() {
 		return true;
 	}
 

convex-core/src/main/java/convex/core/data/MapTree.java

@@ -838,8 +838,13 @@ public AHashMap<K, V> mapEntries(Function<MapEntry<K, V>, MapEntry<K, V>> func)
 	public void validate() throws InvalidDataException {
 		super.validate();
 
-		// Perform child validation
-		validateWithPrefix(getFirstHash(),shift);
+		try {
+			Hash firstHash=getFirstHash();
+			// Perform child validation
+			validateWithPrefix(firstHash,shift);
+		} catch (ClassCastException e) {
+			throw new InvalidDataException("Can't get first hash of map: "+e.getMessage(),e);
+		}
 	}
 
 	@Override

convex-core/src/main/java/convex/core/data/SignedData.java

@@ -323,10 +323,6 @@ public boolean isCanonical() {
 		return true;
 	}
 
-	@Override public final boolean isCVMValue() {
-		return false;
-	}
-
 	@Override
 	public final int getRefCount() {
 		// Value Ref only

convex-core/src/main/java/convex/core/data/prim/ByteFlagExtended.java

@@ -52,7 +52,9 @@ public int encode(byte[] bs, int pos) {
 		return pos;
 	}
 
-	
+	@Override public boolean isCVMValue() {
+		return (tag==Tag.TRUE)||(tag==Tag.FALSE);
+	}
 
 	@Override
 	public long longValue() {

convex-core/src/main/java/convex/core/transactions/ATransaction.java

@@ -88,11 +88,6 @@ public final long getSequence() {
 		return sequence;
 	}
 
-	@Override public final boolean isCVMValue() {
-		// Transactions exist outside CVM only
-		return false;
-	}
-	
 	@Override
 	public AType getType() {
 		return Transaction.INSTANCE;

convex-core/src/test/java/convex/core/data/AdversarialDataTest.java

@@ -13,7 +13,8 @@
 
 import convex.core.Result;
 import convex.core.cvm.AccountStatus;
-import convex.core.cvm.Receipt;
+import convex.core.data.impl.DummyCell;
+import convex.core.data.prim.ByteFlagExtended;
 import convex.core.data.prim.CVMDouble;
 import convex.core.data.prim.CVMLong;
 import convex.core.exceptions.BadFormatException;
@@ -30,17 +31,23 @@
  */
 public class AdversarialDataTest {
 
-	// A value that is valid, but not a first class CVM value
-	public static final ACell NON_CVM=Receipt.create(null);
+	// A value that is valid CAD3, but not a first class CVM value
+	public static final ACell NON_CVM=ByteFlagExtended.create(15);
 
 	// A value that is non-canonical but otherwise valid CVM value
 	public static final Blob NON_CANONICAL=Blob.createRandom(new Random(), Blob.CHUNK_LENGTH+1);
 
 	// A value that is invalid 
 	public static final SetLeaf<CVMLong> NON_VALID=SetLeaf.unsafeCreate(new CVMLong[0]);
 
+	// A value that is illegal in any encoding
+	@SuppressWarnings("exports")
+	public static final DummyCell NON_LEGAL=new DummyCell();
+
+	
 	@Test public void testAssumptions() {
 		assertFalse(NON_CVM.isCVMValue());
+		assertFalse(NON_LEGAL.isCVMValue());
 		assertFalse(NON_CANONICAL.isCanonical());
 		assertThrows(InvalidDataException.class, ()->NON_VALID.validate());
 	}