core/vm: set tracer-observable value of a delegatecall to match parent value ethereum#26632 (#1317)

This is a breaking change in the tracing hooks API as well as semantics of the callTracer:

- CaptureEnter hook provided a nil value argument in case of DELEGATECALL. However to stay consistent with how delegate calls behave in EVM this hook is changed to pass in the value of the parent call.
- callTracer will return parent call's value for DELEGATECALL frames.

---------

Co-authored-by: Chris Ziogas <[email protected]>
Co-authored-by: Sina Mahmoodi <[email protected]>

Author: 3 people

core/vm/evm.go

@@ -320,7 +320,11 @@ func (evm *EVM) DelegateCall(caller ContractRef, addr common.Address, input []by
 
 	// Invoke tracer hooks that signal entering/exiting a call frame
 	if evm.Config.Tracer != nil {
-		evm.Config.Tracer.CaptureEnter(DELEGATECALL, caller.Address(), addr, input, gas, nil)
+		// NOTE: caller must, at all times be a contract. It should never happen
+		// that caller is something other than a Contract.
+		parent := caller.(*Contract)
+		// DELEGATECALL inherits value from parent call
+		evm.Config.Tracer.CaptureEnter(DELEGATECALL, caller.Address(), addr, input, gas, parent.value)
 		defer func(startGas uint64) {
 			evm.Config.Tracer.CaptureExit(ret, startGas-gas, err)
 		}(gas)

eth/tracers/internal/tracetest/testdata/call_tracer/delegatecall.json

@@ -72,7 +72,8 @@
             "input": "0x7d65837a0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000a529806c67cc6486d4d62024471772f47f6fd672",
             "output": "0x0000000000000000000000000000000000000000000000000000000000000001",
             "to": "0x42b02b5deeb78f34cd5ac896473b63e6c99a71a2",
-            "type": "DELEGATECALL"
+            "type": "DELEGATECALL",
+            "value": "0x0"
           }
         ],
         "from": "0x269296dddce321a6bcbaa2f0181127593d732cba",

eth/tracers/internal/tracetest/testdata/call_tracer_withLog/delegatecall.json

@@ -165,7 +165,8 @@
             "to": "0xef3487d24a0702703e04a26cef479e313c8fc7ae",
             "input": "0x24d4e90a0000000000000000000000000000000000000000000000020000000000000000",
             "output": "0x000000000000000000000000000000000000000000000000b17217f7d1cf79ab",
-            "type": "DELEGATECALL"
+            "type": "DELEGATECALL",
+            "value": "0x0"
           },
           {
             "from": "0x8695e5e79dab06fbbb05f445316fa4edb0da30f0",
@@ -174,7 +175,8 @@
             "to": "0xef3487d24a0702703e04a26cef479e313c8fc7ae",
             "input": "0x872fb2b5000000000000000000000000000000000000000000000000c330b3f7006420b8",
             "output": "0x00000000000000000000000000000000000000000000000224bf7df2c80f0878",
-            "type": "DELEGATECALL"
+            "type": "DELEGATECALL",
+            "value": "0x0"
           },
           {
             "from": "0x8695e5e79dab06fbbb05f445316fa4edb0da30f0",
@@ -183,7 +185,8 @@
             "to": "0xef3487d24a0702703e04a26cef479e313c8fc7ae",
             "input": "0x872fb2b50000000000000000000000000000000000000000000000000000000000000000",
             "output": "0x00000000000000000000000000000000000000000000000100000016aee6e8ef",
-            "type": "DELEGATECALL"
+            "type": "DELEGATECALL",
+            "value": "0x0"
           },
           {
             "from": "0x8695e5e79dab06fbbb05f445316fa4edb0da30f0",
@@ -192,7 +195,8 @@
             "to": "0xef3487d24a0702703e04a26cef479e313c8fc7ae",
             "input": "0x24d4e90a00000000000000000000000000000000000000000000000324bf7e0976f5f167",
             "output": "0x0000000000000000000000000000000000000000000000012535c5e5f87ee0d2",
-            "type": "DELEGATECALL"
+            "type": "DELEGATECALL",
+            "value": "0x0"
           },
           {
             "from": "0x8695e5e79dab06fbbb05f445316fa4edb0da30f0",
@@ -201,7 +205,8 @@
             "to": "0xef3487d24a0702703e04a26cef479e313c8fc7ae",
             "input": "0x872fb2b5000000000000000000000000000000000000000000000000c330b3f7006420b8",
             "output": "0x00000000000000000000000000000000000000000000000224bf7df2c80f0878",
-            "type": "DELEGATECALL"
+            "type": "DELEGATECALL",
+            "value": "0x0"
           },
           {
             "from": "0x8695e5e79dab06fbbb05f445316fa4edb0da30f0",
@@ -210,7 +215,8 @@
             "to": "0xef3487d24a0702703e04a26cef479e313c8fc7ae",
             "input": "0x872fb2b500000000000000000000000000000000000000000000000237d37fe5d297a500",
             "output": "0x0000000000000000000000000000000000000000000000093088c407fcbbce38",
-            "type": "DELEGATECALL"
+            "type": "DELEGATECALL",
+            "value": "0x0"
           },
           {
             "from": "0x8695e5e79dab06fbbb05f445316fa4edb0da30f0",
@@ -219,7 +225,8 @@
             "to": "0xef3487d24a0702703e04a26cef479e313c8fc7ae",
             "input": "0x24d4e90a00000000000000000000000000000000000000000000000b554841fac4cad6b0",
             "output": "0x0000000000000000000000000000000000000000000000026d7fc130d6a74cbe",
-            "type": "DELEGATECALL"
+            "type": "DELEGATECALL",
+            "value": "0x0"
           }
         ],
         "value": "0x0",
@@ -387,7 +394,8 @@
                 "data": "0x000000000000000000000000000000000000000000000000de0b6b3a76400000"
               }
             ],
-            "type": "DELEGATECALL"
+            "type": "DELEGATECALL",
+            "value": "0x0"
           }
         ],
         "value": "0x0",