dev: rename CompareProposerPriority to Cmp, add nil check (2.27)

consensus/bor/validator.go

@@ -29,18 +29,23 @@ func NewValidator(address common.Address, votingPower int64) *Validator {
 	}
 }
 
-// Creates a new copy of the validator so we can mutate ProposerPriority.
+// Copy creates a new copy of the validator so we can mutate ProposerPriority.
 // Panics if the validator is nil.
 func (v *Validator) Copy() *Validator {
 	vCopy := *v
 	return &vCopy
 }
 
-// Returns the one with higher ProposerPriority.
-func (v *Validator) CompareProposerPriority(other *Validator) *Validator {
+// Cmp returns the one validator with a higher ProposerPriority.
+// If ProposerPriority is same, it returns the validator with lexicographically smaller address
+func (v *Validator) Cmp(other *Validator) *Validator {
+	// if both of v and other are nil, nil will be returned and that could possibly lead to nil pointer dereference bubbling up the stack
 	if v == nil {
 		return other
 	}
+	if other == nil {
+		return v
+	}
 	if v.ProposerPriority > other.ProposerPriority {
 		return v
 	} else if v.ProposerPriority < other.ProposerPriority {
@@ -53,7 +58,6 @@ func (v *Validator) CompareProposerPriority(other *Validator) *Validator {
 			return other
 		} else {
 			panic("Cannot compare identical validators")
-			return nil
 		}
 	}
 }

consensus/bor/validator_set.go

@@ -182,7 +182,7 @@ func computeMaxMinPriorityDiff(vals *ValidatorSet) int64 {
 func (vals *ValidatorSet) getValWithMostPriority() *Validator {
 	var res *Validator
 	for _, val := range vals.Validators {
-		res = res.CompareProposerPriority(val)
+		res = res.Cmp(val)
 	}
 	return res
 }
@@ -298,7 +298,7 @@ func (vals *ValidatorSet) findProposer() *Validator {
 	var proposer *Validator
 	for _, val := range vals.Validators {
 		if proposer == nil || !bytes.Equal(val.Address.Bytes(), proposer.Address.Bytes()) {
-			proposer = proposer.CompareProposerPriority(val)
+			proposer = proposer.Cmp(val)
 		}
 	}
 	return proposer