feat(eth/tracers): add coinbase to ctx (#12321)

backport ethereum/go-ethereum#30231

Signed-off-by: jsvisa <[email protected]>

Author: jsvisa

eth/tracers/js/goja.go

@@ -249,6 +249,12 @@ func (t *jsTracer) CaptureStart(env *vm.EVM, from libcommon.Address, to libcommo
 	}
 	t.ctx["value"] = valueBig
 	t.ctx["block"] = t.vm.ToValue(env.Context.BlockNumber)
+	coinbase, err := t.toBuf(t.vm, env.Context.Coinbase.Bytes())
+	if err != nil {
+		t.err = err
+		return
+	}
+	t.ctx["coinbase"] = t.vm.ToValue(coinbase)
 	// Update list of precompiles based on current block
 	rules := env.ChainRules()
 	t.activePrecompiles = vm.ActivePrecompiles(rules)

eth/tracers/js/tracer_test.go

@@ -161,6 +161,9 @@ func TestTracer(t *testing.T) {
 			want:     "",
 			fail:     "tracer reached limit for padding memory slice: end 1049600, memorySize 32 at step (<eval>:1:83(23))    in server-side tracer function 'step'",
 			contract: []byte{byte(vm.PUSH1), byte(0xff), byte(vm.PUSH1), byte(0x00), byte(vm.MSTORE8), byte(vm.STOP)},
+		}, { // tests ctx.coinbase
+			code: "{lengths: [], step: function(log) { }, fault: function() {}, result: function(ctx) { var coinbase = ctx.coinbase; return toAddress(coinbase); }}",
+			want: `{"0":0,"1":0,"2":0,"3":0,"4":0,"5":0,"6":0,"7":0,"8":0,"9":0,"10":0,"11":0,"12":0,"13":0,"14":0,"15":0,"16":0,"17":0,"18":0,"19":0}`,
 		},
 	} {
 		if have, err := execTracer(tt.code, tt.contract); tt.want != string(have) || tt.fail != err {