[6.0] GetVar(inputIndex, varId) for reading context variable from another input and fix for Context.getVar

core/shared/src/main/scala/sigma/SigmaDsl.scala

@@ -589,6 +589,17 @@ trait Context {
     */
   def getVar[T](id: Byte)(implicit cT: RType[T]): Option[T]
 
+  /**
+    * A variant of `getVar` to extract a context variable by id and type from any input
+    *
+    * @param inputIndex - input index
+    * @param id - context variable id
+    * @tparam T - expected type of the variable
+    * @return Some(value) if the variable is defined in the context AND has the given type.
+    *         None otherwise
+    */
+  def getVarFromInput[T](inputIndex: Short, id: Byte)(implicit cT: RType[T]): Option[T]
+
   def vars: Coll[AnyValue]
 
   /** Maximum version of ErgoTree currently activated on the network.

core/shared/src/main/scala/sigma/reflection/ReflectionData.scala

@@ -288,6 +288,9 @@ object ReflectionData {
         mkMethod(clazz, "getVar", Array[Class[_]](classOf[Byte], classOf[RType[_]])) { (obj, args) =>
           obj.asInstanceOf[Context].getVar(args(0).asInstanceOf[Byte])(args(1).asInstanceOf[RType[_]])
         },
+        mkMethod(clazz, "getVarFromInput", Array[Class[_]](classOf[Short], classOf[Byte], classOf[RType[_]])) { (obj, args) =>
+          obj.asInstanceOf[Context].getVarFromInput(args(0).asInstanceOf[Short], args(1).asInstanceOf[Byte])(args(2).asInstanceOf[RType[_]])
+        },
         mkMethod(clazz, "headers", Array[Class[_]]()) { (obj, _) =>
           obj.asInstanceOf[Context].headers
         }

data/shared/src/main/scala/sigma/ast/SMethod.scala

@@ -302,6 +302,18 @@ object SMethod {
           (implicit cT: ClassTag[T], cA1: ClassTag[A1], cA2: ClassTag[A2]): RMethod =
     RClass(cT.runtimeClass).getMethod(methodName, cA1.runtimeClass, cA2.runtimeClass)
 
+  /** Return [[Method]] descriptor for the given `methodName` on the given `cT` type.
+    * @param methodName the name of the method to lookup
+    * @param cT the class where to search the methodName
+    * @param cA1 the class of the method's first argument
+    * @param cA2 the class of the method's second argument
+    * @param cA3 the class of the method's third argument
+    */
+  def javaMethodOf[T, A1, A2, A3]
+      (methodName: String)
+          (implicit cT: ClassTag[T], cA1: ClassTag[A1], cA2: ClassTag[A2], cA3: ClassTag[A3]): RMethod =
+    RClass(cT.runtimeClass).getMethod(methodName, cA1.runtimeClass, cA2.runtimeClass, cA3.runtimeClass)
+
   /** Default fallback method call recognizer which builds MethodCall ErgoTree nodes. */
   val MethodCallIrBuilder: PartialFunction[(SigmaBuilder, SValue, SMethod, Seq[SValue], STypeSubst), SValue] = {
     case (builder, obj, method, args, tparamSubst) =>

data/shared/src/main/scala/sigma/ast/SigmaPredef.scala

@@ -146,6 +146,18 @@ object SigmaPredef {
         Seq(ArgInfo("varId", "\\lst{Byte} identifier of context variable")))
     )
 
+    val GetVarFromInputFunc = PredefinedFunc("getVarFromInput",
+      Lambda(Array(paramT), Array("inputId" -> SShort, "varId" -> SByte), SOption(tT), None),
+      PredefFuncInfo(
+        { case (Ident(_, SFunc(_, SOption(rtpe), _)), Seq(inputId: Constant[SNumericType]@unchecked, varId: Constant[SNumericType]@unchecked)) =>
+          mkMethodCall(Context, SContextMethods.getVarFromInputMethod, IndexedSeq(SShort.downcast(inputId.value.asInstanceOf[AnyVal]), SByte.downcast(varId.value.asInstanceOf[AnyVal])), Map(tT -> rtpe))
+        }),
+      OperationInfo(MethodCall,
+        "Get context variable with given \\lst{varId} and type.",
+        Seq(ArgInfo("inputId", "\\lst{Byte} index of input to read context variable from"),
+            ArgInfo("varId", "\\lst{Byte} identifier of context variable")))
+    )
+
     def PKFunc(networkPrefix: NetworkPrefix) = PredefinedFunc("PK",
       Lambda(Array("input" -> SString), SSigmaProp, None),
       PredefFuncInfo(
@@ -468,6 +480,7 @@ object SigmaPredef {
       ExecuteFromVarFunc,
       ExecuteFromSelfRegFunc,
       SerializeFunc,
+      GetVarFromInputFunc,
       FromBigEndianBytesFunc
     ).map(f => f.name -> f).toMap
 

data/shared/src/main/scala/sigma/ast/methods.scala

@@ -1677,16 +1677,52 @@ case object SContextMethods extends MonoTypeMethods {
   lazy val selfBoxIndexMethod = propertyCall("selfBoxIndex", SInt, 8, FixedCost(JitCost(20)))
   lazy val lastBlockUtxoRootHashMethod = property("LastBlockUtxoRootHash", SAvlTree, 9, LastBlockUtxoRootHash)
   lazy val minerPubKeyMethod = property("minerPubKey", SByteArray, 10, MinerPubkey)
-  lazy val getVarMethod = SMethod(
+
+  lazy val getVarV5Method = SMethod(
     this, "getVar", SFunc(ContextFuncDom, SOption(tT), Array(paramT)), 11, GetVar.costKind)
     .withInfo(GetVar, "Get context variable with given \\lst{varId} and type.",
       ArgInfo("varId", "\\lst{Byte} identifier of context variable"))
 
-  protected override def getMethods() = super.getMethods() ++ Seq(
+  lazy val getVarV6Method = SMethod(
+    this, "getVar", SFunc(ContextFuncDom, SOption(tT), Array(paramT)), 11, GetVar.costKind, Seq(tT))
+    .withIRInfo(
+      MethodCallIrBuilder,
+      javaMethodOf[Context, Byte, RType[_]]("getVar"),
+      { mtype => Array(mtype.tRange.asOption[SType].elemType) })
+    .withInfo(MethodCall, "Get context variable with given \\lst{varId} and type.")
+
+  lazy val getVarFromInputMethod = SMethod(
+    this, "getVarFromInput", SFunc(Array(SContext, SShort, SByte), SOption(tT), Array(paramT)), 12, GetVar.costKind, Seq(tT))
+    .withIRInfo(
+      MethodCallIrBuilder,
+      javaMethodOf[Context, Short, Byte, RType[_]]("getVarFromInput"),
+      { mtype => Array(mtype.tRange.asOption[SType].elemType) })
+    .withInfo(MethodCall, "Get context variable with given \\lst{varId} and type.",
+      ArgInfo("inputIdx", "Index of input to read variable from."),
+      ArgInfo("varId", "Index of variable.")
+    )
+
+  private lazy val commonMethods = super.getMethods() ++ Array(
     dataInputsMethod, headersMethod, preHeaderMethod, inputsMethod, outputsMethod, heightMethod, selfMethod,
-    selfBoxIndexMethod, lastBlockUtxoRootHashMethod, minerPubKeyMethod, getVarMethod
+    selfBoxIndexMethod, lastBlockUtxoRootHashMethod, minerPubKeyMethod
+  )
+
+  private lazy val v5Methods = commonMethods ++ Seq(
+    getVarV5Method
+  )
+
+  private lazy val v6Methods = commonMethods ++ Seq(
+    getVarV6Method, getVarFromInputMethod
   )
 
+  protected override def getMethods(): Seq[SMethod] = {
+    if (VersionContext.current.isV6SoftForkActivated) {
+      v6Methods
+    } else {
+      v5Methods
+    }
+  }
+
   /** Names of methods which provide blockchain context.
    * This value can be reused where necessary to avoid allocations. */
   val BlockchainContextMethodNames: IndexedSeq[String] = Array(

data/shared/src/main/scala/sigma/interpreter/ContextExtension.scala

@@ -16,8 +16,15 @@ import sigma.serialization.{SigmaByteReader, SigmaByteWriter, SigmaSerializer}
   * @param values internal container of the key-value pairs
   */
 case class ContextExtension(values: scala.collection.Map[Byte, EvaluatedValue[_ <: SType]]) {
-  def add(bindings: VarBinding*): ContextExtension =
+  def add(bindings: VarBinding*): ContextExtension = {
     ContextExtension(values ++ bindings)
+  }
+
+  /**
+    * @param varId - index of context variable
+    * @return context variable with provided index or None if it is not there
+    */
+  def get(varId: Byte): Option[EvaluatedValue[_ <: SType]] = values.get(varId)
 }
 
 object ContextExtension {

docs/LangSpec.md

@@ -919,7 +919,7 @@ def longToByteArray(input: Long): Coll[Byte]
 def decodePoint(bytes: Coll[Byte]): GroupElement 
 
 
-/** Extracts Context variable by id and type.
+/** Extracts Context variable from SELF input by id and type.
   * ErgoScript is typed, so accessing a the variables is an operation which involves
   * some expected type given in brackets. Thus `getVar[Int](id)` expression should
   * evaluate to a valid value of the `Option[Int]` type.
@@ -976,6 +976,18 @@ def decodePoint(bytes: Coll[Byte]): GroupElement
   */
 def getVar[T](tag: Int): Option[T]
 
+/** Extracts Context variable from any input by input index, variable id and variable type.
+  * Unlike getVar, it is not throwing exception when expected type does not match real type of the variable.
+  * Thus it can be used to get context variable from self without exception, using selfBoxIndex, e.g. 
+  * <pre class="stHighlight">
+  *   {
+  *       val idx = CONTEXT.selfBoxIndex
+  *       sigmaProp(CONTEXT.getVarFromInput[Int](idx.toShort, 1.toByte).get == 5)
+  *   }
+  * </pre>
+  */
+def getVarFromInput[T](inputId: Short, varId: Byte): Option[T]
+
 /** Construct a new SigmaProp value representing public key of Diffie Hellman
   * signature protocol. When executed as part of Sigma protocol allow to provide
   * for a verifier a zero-knowledge proof of secret knowledge.

interpreter/shared/src/main/scala/org/ergoplatform/ErgoLikeContext.scala

@@ -168,7 +168,7 @@ class ErgoLikeContext(val lastBlockUtxoRoot: AvlTreeData,
         syntax.error(s"Undefined context property: currentErgoTreeVersion"))
     CContext(
       dataInputs, headers, preHeader, inputs, outputs, preHeader.height, selfBox, selfIndex, avlTree,
-      preHeader.minerPk.getEncoded, vars, activatedScriptVersion, ergoTreeVersion)
+      preHeader.minerPk.getEncoded, vars, spendingTransaction, activatedScriptVersion, ergoTreeVersion)
   }
 
 

interpreter/shared/src/main/scala/sigmastate/eval/CContext.scala

@@ -1,8 +1,11 @@
 package sigmastate.eval
 
 import debox.cfor
+import org.ergoplatform.{ErgoLikeTransactionTemplate, UnsignedInput}
+import sigma.Evaluation.stypeToRType
 import sigma.Extensions.ArrayOps
 import sigma._
+import sigma.ast.SType
 import sigma.data._
 import sigma.exceptions.InvalidType
 
@@ -24,6 +27,7 @@ case class CContext(
     lastBlockUtxoRootHash: AvlTree,
     _minerPubKey: Coll[Byte],
     vars: Coll[AnyValue],
+    spendingTransaction: ErgoLikeTransactionTemplate[_ <: UnsignedInput],
     override val activatedScriptVersion: Byte,
     override val currentErgoTreeVersion: Byte
 ) extends Context {
@@ -69,6 +73,14 @@ case class CContext(
     } else None
   }
 
+  override def getVarFromInput[T](inputIndex: Short, id: Byte)(implicit tT: RType[T]): Option[T] = {
+    spendingTransaction.inputs.lift(inputIndex).flatMap(_.extension.get(id)) match {
+      case Some(v) if stypeToRType[SType](v.tpe) == tT => Some(v.value.asInstanceOf[T])
+      case _ =>
+        None
+    }
+  }
+
   /** Return a new context instance with variables collection updated.
     * @param bindings  a new binding of the context variables with new values.
     * @return a new instance (if `bindings` non-empty) with the specified bindings.

interpreter/shared/src/test/scala/special/sigma/ContractsTestkit.scala

@@ -47,7 +47,7 @@ trait ContractsTestkit {
     new CContext(
       noInputs.toColl, noHeaders, dummyPreHeader,
       inputs.toColl, outputs.toColl, height, self, inputs.indexOf(self), tree,
-      minerPk.toColl, vars.toColl, activatedScriptVersion, currErgoTreeVersion)
+      minerPk.toColl, vars.toColl, null, activatedScriptVersion, currErgoTreeVersion)
 
   def newContext(
       height: Int,

sc/shared/src/main/scala/sigma/compiler/ir/GraphBuilding.scala

@@ -1,6 +1,7 @@
 package sigma.compiler.ir
 
 import org.ergoplatform._
+import sigma.ast.SType.tT
 import sigma.Evaluation.stypeToRType
 import sigma.ast.SType.tT
 import sigma.ast.TypeCodes.LastConstantCode
@@ -1059,6 +1060,15 @@ trait GraphBuilding extends Base with DefRewriting { IR: IRContext =>
               ctx.LastBlockUtxoRootHash
             case SContextMethods.minerPubKeyMethod.name =>
               ctx.minerPubKey
+            case SContextMethods.getVarV6Method.name =>
+              val c2 = asRep[Byte](argsV(0))
+              val c3 = stypeToElem(typeSubst.apply(tT))
+              ctx.getVar(c2)(c3)
+            case SContextMethods.getVarFromInputMethod.name =>
+              val c1 = asRep[Short](argsV(0))
+              val c2 = asRep[Byte](argsV(1))
+              val c3 = stypeToElem(typeSubst.apply(tT))
+              ctx.getVarFromInput(c1, c2)(c3)
             case _ => throwError()
           }
           case (tree: Ref[AvlTree]@unchecked, SAvlTreeMethods) => method.name match {

sc/shared/src/main/scala/sigma/compiler/ir/GraphIRReflection.scala

@@ -349,6 +349,9 @@ object GraphIRReflection {
         mkMethod(clazz, "getVar", Array[Class[_]](classOf[Base#Ref[_]], classOf[TypeDescs#Elem[_]])) { (obj, args) =>
           obj.asInstanceOf[ctx.Context].getVar(args(0).asInstanceOf[ctx.Ref[Byte]])(args(1).asInstanceOf[ctx.Elem[_]])
         },
+        mkMethod(clazz, "getVarFromInput", Array[Class[_]](classOf[Base#Ref[_]], classOf[Base#Ref[_]], classOf[TypeDescs#Elem[_]])) { (obj, args) =>
+          obj.asInstanceOf[ctx.Context].getVarFromInput(args(0).asInstanceOf[ctx.Ref[Short]], args(1).asInstanceOf[ctx.Ref[Byte]])(args(2).asInstanceOf[ctx.Elem[_]])
+        },
         mkMethod(clazz, "headers", Array[Class[_]]()) { (obj, args) =>
           obj.asInstanceOf[ctx.Context].headers
         }

sc/shared/src/main/scala/sigma/compiler/ir/TreeBuilding.scala

@@ -1,6 +1,7 @@
 package sigma.compiler.ir
 
 import org.ergoplatform._
+import sigma.VersionContext
 import sigma.Evaluation.{rtypeToSType, stypeToRType}
 import sigma.ast.SType.tT
 import sigma.ast._

sc/shared/src/main/scala/sigma/compiler/ir/wrappers/sigma/SigmaDslUnit.scala

@@ -92,6 +92,7 @@ import scalan._
       def preHeader: Ref[PreHeader];
       def minerPubKey: Ref[Coll[Byte]];
       def getVar[T](id: Ref[Byte])(implicit cT: Elem[T]): Ref[WOption[T]];
+      def getVarFromInput[T](inputId: Ref[Short], id: Ref[Byte])(implicit cT: Elem[T]): Ref[WOption[T]];
     };
     trait SigmaDslBuilder extends Def[SigmaDslBuilder] {
       def Colls: Ref[CollBuilder];

sc/shared/src/main/scala/sigma/compiler/ir/wrappers/sigma/impl/SigmaDslImpl.scala

@@ -1626,10 +1626,19 @@ object Context extends EntityObject("Context") {
     }
 
     override def getVar[T](id: Ref[Byte])(implicit cT: Elem[T]): Ref[WOption[T]] = {
+      val st = Evaluation.rtypeToSType(cT.sourceType)
       asRep[WOption[T]](mkMethodCall(self,
         ContextClass.getMethod("getVar", classOf[Sym], classOf[Elem[_]]),
         Array[AnyRef](id, cT),
-        true, false, element[WOption[T]]))
+        true, false, element[WOption[T]], Map(tT -> st)))
+    }
+
+    override def getVarFromInput[T](inputId: Ref[Short], varId: Ref[Byte])(implicit cT: Elem[T]): Ref[WOption[T]] = {
+      val st = Evaluation.rtypeToSType(cT.sourceType)
+      asRep[WOption[T]](mkMethodCall(self,
+        ContextClass.getMethod("getVarFromInput", classOf[Sym], classOf[Sym], classOf[Elem[_]]),
+        Array[AnyRef](inputId, varId, cT),
+        true, false, element[WOption[T]], Map(tT -> st)))
     }
 
   }
@@ -1723,10 +1732,19 @@ object Context extends EntityObject("Context") {
     }
 
     def getVar[T](id: Ref[Byte])(implicit cT: Elem[T]): Ref[WOption[T]] = {
+      val st = Evaluation.rtypeToSType(cT.sourceType)
       asRep[WOption[T]](mkMethodCall(source,
         ContextClass.getMethod("getVar", classOf[Sym], classOf[Elem[_]]),
         Array[AnyRef](id, cT),
-        true, true, element[WOption[T]]))
+        true, true, element[WOption[T]], Map(tT -> st)))
+    }
+
+    def getVarFromInput[T](inputId: Ref[Short], varId: Ref[Byte])(implicit cT: Elem[T]): Ref[WOption[T]] = {
+      val st = Evaluation.rtypeToSType(cT.sourceType)
+      asRep[WOption[T]](mkMethodCall(source,
+        ContextClass.getMethod("getVarFromInput", classOf[Sym], classOf[Sym], classOf[Elem[_]]),
+        Array[AnyRef](inputId, varId, cT),
+        true, true, element[WOption[T]], Map(tT -> st)))
     }
   }
 
@@ -1745,7 +1763,7 @@ object Context extends EntityObject("Context") {
     override protected def collectMethods: Map[RMethod, MethodDesc] = {
       super.collectMethods ++
         Elem.declaredMethods(RClass(classOf[Context]), RClass(classOf[SContext]), Set(
-        "OUTPUTS", "INPUTS", "dataInputs", "HEIGHT", "SELF", "selfBoxIndex", "LastBlockUtxoRootHash", "headers", "preHeader", "minerPubKey", "getVar", "vars"
+        "OUTPUTS", "INPUTS", "dataInputs", "HEIGHT", "SELF", "selfBoxIndex", "LastBlockUtxoRootHash", "headers", "preHeader", "minerPubKey", "getVar", "getVarFromInput", "vars"
         ))
     }
   }

sc/shared/src/main/scala/sigma/compiler/phases/SigmaTyper.scala

@@ -134,8 +134,19 @@ class SigmaTyper(val builder: SigmaBuilder,
       res
 
     case Apply(ApplyTypes(sel @ Select(obj, n, _), Seq(rangeTpe)), args) =>
+      // downcast getVarFromInput arguments to short and byte
+      val nArgs = if (n == SContextMethods.getVarFromInputMethod.name &&
+          args.length == 2 &&
+          args(0).isInstanceOf[Constant[_]] &&
+          args(1).isInstanceOf[Constant[_]] &&
+          args(0).tpe.isNumType &&
+          args(1).tpe.isNumType) {
+        IndexedSeq(ShortConstant(SShort.downcast(args(0).asInstanceOf[Constant[SNumericType]].value.asInstanceOf[AnyVal])).withSrcCtx(args(0).sourceContext),
+          ByteConstant(SByte.downcast(args(1).asInstanceOf[Constant[SNumericType]].value.asInstanceOf[AnyVal])).withSrcCtx(args(1).sourceContext))
+      } else args
+
       val newObj = assignType(env, obj)
-      val newArgs = args.map(assignType(env, _))
+      val newArgs = nArgs.map(assignType(env, _))
       newObj.tpe match {
         case p: SProduct =>
           MethodsContainer.getMethod(p, n) match {
@@ -155,7 +166,7 @@ class SigmaTyper(val builder: SigmaBuilder,
                   .getOrElse(mkMethodCall(newObj, method, newArgs, subst))
               } else {
                 val newSelect = mkSelect(newObj, n, Some(concrFunTpe)).withSrcCtx(sel.sourceContext)
-                mkApply(newSelect, newArgs.toArray[SValue])
+                mkApply(newSelect, newArgs)
               }
             case Some(method) =>
               error(s"Don't know how to handle method $method in obj $p", sel.sourceContext)
@@ -221,6 +232,11 @@ class SigmaTyper(val builder: SigmaBuilder,
             case (Ident(GetVarFunc.name | ExecuteFromVarFunc.name, _), Seq(id: Constant[SNumericType]@unchecked))
               if id.tpe.isNumType =>
                 Seq(ByteConstant(SByte.downcast(id.value.asInstanceOf[AnyVal])).withSrcCtx(id.sourceContext))
+            case (Ident(SContextMethods.getVarFromInputMethod.name, _),
+                  Seq(inputId: Constant[SNumericType]@unchecked, varId: Constant[SNumericType]@unchecked))
+                  if inputId.tpe.isNumType && varId.tpe.isNumType =>
+              Seq(ShortConstant(SShort.downcast(inputId.value.asInstanceOf[AnyVal])).withSrcCtx(inputId.sourceContext),
+                ByteConstant(SByte.downcast(varId.value.asInstanceOf[AnyVal])).withSrcCtx(varId.sourceContext))
             case _ => typedArgs
           }
           val actualTypes = adaptedTypedArgs.map(_.tpe)
@@ -409,11 +425,6 @@ class SigmaTyper(val builder: SigmaBuilder,
           error(s"Invalid application of type arguments $app: function $input doesn't have type parameters", input.sourceContext)
       }
 
-//    case app @ ApplyTypes(in, targs) =>
-//      val newIn = assignType(env, in)
-//      ApplyTypes(newIn, targs)
-//      error(s"Invalid application of type arguments $app: expression doesn't have type parameters")
-
     case If(c, t, e) =>
       val c1 = assignType(env, c).asValue[SBoolean.type]
       val t1 = assignType(env, t)

sc/shared/src/test/scala/sigma/LanguageSpecificationV5.scala

@@ -4533,6 +4533,7 @@ class LanguageSpecificationV5 extends LanguageSpecificationBase { suite =>
           .append(Coll[AnyValue](
             CAnyValue(Helpers.decodeBytes("00")),
             CAnyValue(true))),
+      spendingTransaction = null,
       activatedScriptVersion = activatedVersionInTests,
       currentErgoTreeVersion = ergoTreeVersionInTests
     )