fix: skip invalid locations (#1357)

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This PR does the following

* If a location in the locations array have invalid values (i.e. :-
every slice element's col and line are 0 or less), we will remove the
location entry.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **Bug Fixes**
* Improved error-location handling: invalid or incomplete location
entries are filtered out; the locations field is removed when empty or
when omission is requested, while preserving valid entries.

* **Tests**
* Added comprehensive tests covering omission-flag behavior, removal vs.
preservation cases, non-array/empty objects, mixed valid/invalid
locations, and large datasets.

* **Chores**
  * Internal cleanup and small refactors to error-field handling.

<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

## Checklist

- [ ] I have discussed my proposed changes in an issue and have received
approval to proceed.
- [ ] I have followed the coding standards of the project.
- [ ] Tests or benchmarks have been added or updated.

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Please add any additional information or context regarding your changes
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Author: SkArchon

v2/pkg/engine/resolve/const.go

@@ -2,6 +2,10 @@ package resolve
 
 import "errors"
 
+const (
+	locationsField = "locations"
+)
+
 var (
 	lBrace                    = []byte("{")
 	rBrace                    = []byte("}")
@@ -16,7 +20,7 @@ var (
 	literalFalse              = []byte("false")
 	literalErrors             = []byte("errors")
 	literalMessage            = []byte("message")
-	literalLocations          = []byte("locations")
+	literalLocations          = []byte(locationsField)
 	literalPath               = []byte("path")
 	literalUnderscoreEntities = []byte("_entities")
 	literalExtensions         = []byte("extensions")
@@ -35,19 +39,3 @@ var (
 	errHeaderPathInvalid           = errors.New("invalid header path: header variables must be of this format: .request.header.{{ key }} ")
 	ErrUnableToResolve             = errors.New("unable to resolve operation")
 )
-
-var (
-	errorPaths = [][]string{
-		{"message"},
-		{"locations"},
-		{"path"},
-		{"extensions"},
-	}
-)
-
-const (
-	errorsMessagePathIndex    = 0
-	errorsLocationsPathIndex  = 1
-	errorsPathPathIndex       = 2
-	errorsExtensionsPathIndex = 3
-)

v2/pkg/engine/resolve/loader.go

@@ -936,12 +936,38 @@ func (l *Loader) optionallyOmitErrorFields(values []*astjson.Value) {
 
 // optionallyOmitErrorLocations removes the "locations" object from all values.
 func (l *Loader) optionallyOmitErrorLocations(values []*astjson.Value) {
-	if !l.omitSubgraphErrorLocations {
-		return
-	}
+	arena := astjson.Arena{}
+
 	for _, value := range values {
-		if value.Exists("locations") {
-			value.Del("locations")
+		// If the flag is set, delete all locations
+		if !value.Exists(locationsField) || l.omitSubgraphErrorLocations {
+			value.Del(locationsField)
+			continue
+		}
+
+		// Create a new array via astjson we can append to the valid types
+		validLocations := arena.NewArray()
+		validIndex := 0
+
+		// GetArray will return nil if not an array which will not be ranged over
+		allLocations := value.Get(locationsField)
+		for _, loc := range allLocations.GetArray() {
+			line := loc.Get("line")
+			column := loc.Get("column")
+
+			// Keep location only if both line and column are > 0 (spec says 0 is invalid)
+			// In case it is not an int, 0 will be returned which is invalid anyway
+			if line.GetInt() > 0 && column.GetInt() > 0 {
+				validLocations.SetArrayItem(validIndex, loc)
+				validIndex++
+			}
+		}
+
+		// If all locations were invalid, delete the locations field
+		if len(validLocations.GetArray()) > 0 {
+			value.Set(locationsField, validLocations)
+		} else {
+			value.Del(locationsField)
 		}
 	}
 }