fix: use i64 for shards/ranges

Using int is problematic because it's platform-dependent. On 32-bit
platform this may cause issues if SubjectShards > 2,147,483,647. This
will make the number go negative and ranges might not match.

Author: rasendubi

eppoclient/client.go

@@ -89,12 +89,12 @@ func (ec *EppoClient) getAssignment(subjectKey string, flagKey string, subjectAt
 
 	// Get assigned variation
 	assignmentKey := "assignment-" + subjectKey + "-" + flagKey
-	shard := getShard(assignmentKey, int64(config.SubjectShards))
+	shard := getShard(assignmentKey, config.SubjectShards)
 	variations := allocation.Variations
 	var variationShard Variation
 
 	for _, variation := range variations {
-		if isShardInRange(int(shard), variation.ShardRange) {
+		if isShardInRange(shard, variation.ShardRange) {
 			variationShard = variation
 		}
 	}
@@ -137,9 +137,9 @@ func getSubjectVariationOverride(experimentConfig experimentConfiguration, subje
 	return Null()
 }
 
-func isInExperimentSample(subjectKey string, flagKey string, subjectShards int, percentExposure float32) bool {
+func isInExperimentSample(subjectKey string, flagKey string, subjectShards int64, percentExposure float32) bool {
 	shardKey := "exposure-" + subjectKey + "-" + flagKey
-	shard := getShard(shardKey, int64(subjectShards))
+	shard := getShard(shardKey, subjectShards)
 
 	return float64(shard) <= float64(percentExposure)*float64(subjectShards)
 }

eppoclient/configurationstore.go

@@ -22,7 +22,7 @@ type Allocation struct {
 type experimentConfiguration struct {
 	Name          string                `json:"name"`
 	Enabled       bool                  `json:"enabled"`
-	SubjectShards int                   `json:"subjectShards"`
+	SubjectShards int64                 `json:"subjectShards"`
 	Rules         []rule                `json:"rules"`
 	Overrides     map[string]Value      `json:"typedOverrides"`
 	Allocations   map[string]Allocation `json:"allocations"`

eppoclient/shard.go

@@ -6,8 +6,8 @@ import (
 )
 
 type shardRange struct {
-	Start int `json:"start"`
-	End   int `json:"end"`
+	Start int64 `json:"start"`
+	End   int64 `json:"end"`
 }
 
 func getShard(input string, subjectShards int64) int64 {
@@ -17,6 +17,6 @@ func getShard(input string, subjectShards int64) int64 {
 	return intVal % subjectShards
 }
 
-func isShardInRange(shard int, shardRange shardRange) bool {
+func isShardInRange(shard int64, shardRange shardRange) bool {
 	return shard >= shardRange.Start && shard < shardRange.End
 }

eppoclient/shard_test.go

@@ -27,7 +27,7 @@ func Test_isShardInRange_Fail(t *testing.T) {
 	input := 5
 	inputRange := shardRange{Start: 1, End: 5}
 	expected := false
-	result := isShardInRange(input, inputRange)
+	result := isShardInRange(int64(input), inputRange)
 
 	assert.Equal(t, expected, result)
 }
@@ -36,7 +36,7 @@ func Test_isShardInRange_Success(t *testing.T) {
 	input := 3
 	inputRange := shardRange{Start: 1, End: 7}
 	expected := true
-	result := isShardInRange(input, inputRange)
+	result := isShardInRange(int64(input), inputRange)
 
 	assert.Equal(t, expected, result)
 }