From 8d6f80592b3a929b9e6fa29086b084e2a2aae75a Mon Sep 17 00:00:00 2001
From: Ethan Buchman <ethan@coinculture.info>
Date: Fri, 26 Jun 2015 01:36:31 +0000
Subject: [PATCH] some panics, dont panic on invalid opcode

---
 state/execution.go | 18 ++++++++----------
 state/genesis.go   |  2 +-
 vm/native.go       | 10 ++--------
 vm/vm.go           |  7 ++++++-
 4 files changed, 17 insertions(+), 20 deletions(-)

diff --git a/state/execution.go b/state/execution.go
index 65d161404..84e589ebe 100644
--- a/state/execution.go
+++ b/state/execution.go
@@ -293,15 +293,6 @@ func adjustByOutputs(accounts map[string]*account.Account, outs []*types.TxOutpu
 // If the tx is invalid, an error will be returned.
 // Unlike ExecBlock(), state will not be altered.
 func ExecTx(blockCache *BlockCache, tx_ types.Tx, runCall bool, evc events.Fireable) error {
-
-	defer func() {
-		if r := recover(); r != nil {
-			err := errors.New(Fmt("Recovered from panic in ExecTx", "err", r, "tx", tx_))
-			log.Error(err.Error())
-			// TODO return error
-		}
-	}()
-
 	// TODO: do something with fees
 	fees := int64(0)
 	_s := blockCache.State() // hack to access validators and block height
@@ -822,6 +813,10 @@ func ExecTx(blockCache *BlockCache, tx_ types.Tx, runCall bool, evc events.Firea
 
 // Get permission on an account or fall back to global value
 func HasPermission(state AccountGetter, acc *account.Account, perm ptypes.PermFlag) bool {
+	if perm > ptypes.AllBasePermissions {
+		panic("Checking an unknown permission in state should never happen")
+	}
+
 	if acc == nil {
 		// TODO
 		// this needs to fall back to global or do some other specific things
@@ -830,7 +825,10 @@ func HasPermission(state AccountGetter, acc *account.Account, perm ptypes.PermFl
 
 	v, err := acc.Permissions.Base.Get(perm)
 	if _, ok := err.(ptypes.ErrValueNotSet); ok {
-		return HasPermission(state, state.GetAccount(ptypes.GlobalPermissionsAddress), perm)
+		if state == nil {
+			panic("All known global permissions should be set!")
+		}
+		return HasPermission(nil, state.GetAccount(ptypes.GlobalPermissionsAddress), perm)
 	}
 	return v
 }
diff --git a/state/genesis.go b/state/genesis.go
index 6fcc40e14..fdee9e3fd 100644
--- a/state/genesis.go
+++ b/state/genesis.go
@@ -108,7 +108,7 @@ func MakeGenesisState(db dbm.DB, genDoc *GenesisDoc) *State {
 	if genDoc.Params != nil && genDoc.Params.GlobalPermissions != nil {
 		globalPerms = genDoc.Params.GlobalPermissions
 		// XXX: make sure the set bits are all true
-		// Without it the HasPermission() functions will recurse till death
+		// Without it the HasPermission() functions will fail
 		globalPerms.Base.SetBit = ptypes.AllSet
 	}
 
diff --git a/vm/native.go b/vm/native.go
index 003f557ff..27f2e8f4b 100644
--- a/vm/native.go
+++ b/vm/native.go
@@ -53,10 +53,7 @@ func sha256Func(input []byte, gas *int64) (output []byte, err error) {
 	// Hash
 	hasher := sha256.New()
 	// CONTRACT: this does not err
-	_, err = hasher.Write(input)
-	if err != nil {
-		panic(err)
-	}
+	hasher.Write(input)
 	return hasher.Sum(nil), nil
 }
 
@@ -71,10 +68,7 @@ func ripemd160Func(input []byte, gas *int64) (output []byte, err error) {
 	// Hash
 	hasher := ripemd160.New()
 	// CONTRACT: this does not err
-	_, err = hasher.Write(input)
-	if err != nil {
-		panic(err)
-	}
+	hasher.Write(input)
 	return LeftPadBytes(hasher.Sum(nil), 32), nil
 }
 
diff --git a/vm/vm.go b/vm/vm.go
index f8c6e2bf2..8087443c6 100644
--- a/vm/vm.go
+++ b/vm/vm.go
@@ -90,11 +90,16 @@ func (vm *VM) EnablePermissions() {
 	vm.perms = true
 }
 
+// XXX: it is the duty of the contract writer to call known permissions
+// we do not convey if a permission is not set
+// (unlike in state/execution, where we guarantee HasPermission is called
+// on known permissions and panics else)
 func HasPermission(appState AppState, acc *Account, perm ptypes.PermFlag) bool {
 	v, err := acc.Permissions.Base.Get(perm)
 	if _, ok := err.(ptypes.ErrValueNotSet); ok {
 		if appState == nil {
-			panic(fmt.Sprintf("Global permission value not set for %b", perm))
+			fmt.Printf("\n\n***** Unknown permission %b! ********\n\n", perm)
+			return false
 		}
 		return HasPermission(nil, appState.GetAccount(ptypes.GlobalPermissionsAddress256), perm)
 	}