MB-65807: Graceful handling of non-conforming polygon data (#2165)

Geo's `extract3DCoordinates` does not validate input data which can
cause malformed polygon data to cause a panic:

```
panic: reflect: call of reflect.Value.Index on map Value

panic({0x100a9e0c0?, 0x140001163a8?})
        /opt/homebrew/opt/go/libexec/src/runtime/panic.go:770 +0x124
reflect.Value.Index({0x100a9ffe0?, 0x14000118c00?, 0x14000062c58?}, 0x1008913c8?)
        /opt/homebrew/opt/go/libexec/src/reflect/value.go:1447 +0x170
github.com/blevesearch/bleve/v2/geo.extract3DCoordinates({0x100a9ffe0?, 0x14000118c00?})
        /Users/abhinav.dangeti/Documents/go/src/github.com/blevesearch/bleve/geo/parse.go:245 +0x12c
github.com/blevesearch/bleve/v2/geo.ExtractGeoShapeCoordinates({0x100a9ffe0?, 0x14000118c00?}, {0x100a24659, 0x7})
```

See: https://pkg.go.dev/reflect#Value.IsValid

Author: abhinavdangeti

geo/parse.go

@@ -236,14 +236,19 @@ func extract2DCoordinates(thing interface{}) [][]float64 {
 
 func extract3DCoordinates(thing interface{}) (c [][][]float64) {
 	coords := reflect.ValueOf(thing)
-	for i := 0; i < coords.Len(); i++ {
-		vals := coords.Index(i)
-
-		edges := vals.Interface()
-		if es, ok := edges.([]interface{}); ok {
-			loop := extract2DCoordinates(es)
-			if len(loop) > 0 {
-				c = append(c, loop)
+	if !coords.IsValid() {
+		return nil
+	}
+
+	if coords.Kind() == reflect.Slice {
+		for i := 0; i < coords.Len(); i++ {
+			vals := coords.Index(i)
+			edges := vals.Interface()
+			if es, ok := edges.([]interface{}); ok {
+				loop := extract2DCoordinates(es)
+				if len(loop) > 0 {
+					c = append(c, loop)
+				}
 			}
 		}
 	}

geo/parse_test.go

@@ -15,12 +15,12 @@
 package geo
 
 import (
+	"encoding/json"
 	"reflect"
 	"testing"
 )
 
 func TestExtractGeoPoint(t *testing.T) {
-
 	tests := []struct {
 		in      interface{}
 		lon     float64
@@ -353,3 +353,103 @@ func TestExtractGeoShape(t *testing.T) {
 		}
 	}
 }
+
+func TestExtractGeoShapeCoordinates(t *testing.T) {
+	tests := []struct {
+		x        []byte
+		typ      string
+		expectOK bool
+	}{
+		{
+			x: []byte(`[
+				[
+					[77.58894681930542,12.976498523818783],
+					[77.58677959442139,12.974533005048169],
+					[77.58894681930542,12.976498523818783]
+				]
+			]`),
+			typ:      PolygonType,
+			expectOK: true,
+		},
+		{ // Invalid construct, but handled
+			x: []byte(`[
+				[
+					{"lon":77.58894681930542,"lat":12.976498523818783},
+					{"lon":77.58677959442139,"lat":12.974533005048169},
+					{"lon":77.58894681930542,"lat":12.976498523818783}
+				]
+			]`),
+			typ:      PolygonType,
+			expectOK: false,
+		},
+		{ // Invalid construct causes panic (within extract3DCoordinates), fix MB-65807
+			x: []byte(`{
+				"coordinates": [
+					[77.58894681930542,12.976498523818783],
+					[77.58677959442139,12.974533005048169],
+					[77.58894681930542,12.976498523818783]
+				]
+			}`),
+			typ:      PolygonType,
+			expectOK: false,
+		},
+		{
+			x: []byte(`[
+				[
+					[
+						[-0.163421630859375,51.531600743186644],
+						[-0.15277862548828125,51.52455221546295],
+						[-0.15895843505859375,51.53693981046689],
+						[-0.163421630859375,51.531600743186644]
+					]
+				],
+				[
+					[
+						[-0.1902008056640625,51.5091698216777],
+						[-0.1599884033203125,51.51322956905176],
+						[-0.1902008056640625,51.5091698216777]
+					]
+				]
+			]`),
+			typ:      MultiPolygonType,
+			expectOK: true,
+		},
+		{ // Invalid construct causes panic (within extract3DCoordinates), fix MB-65807
+			x: []byte(`[
+				{
+					"coordinates": [
+						[-0.163421630859375,51.531600743186644],
+						[-0.15277862548828125,51.52455221546295],
+						[-0.15895843505859375,51.53693981046689],
+						[-0.163421630859375,51.531600743186644]
+					]
+				},
+				{
+					"coordinates": [
+						[-0.1902008056640625,51.5091698216777],
+						[-0.1599884033203125,51.51322956905176],
+						[-0.1902008056640625,51.5091698216777]
+					]
+				}
+			]`),
+			typ:      MultiPolygonType,
+			expectOK: false,
+		},
+	}
+
+	for i := range tests {
+		var x interface{}
+		if err := json.Unmarshal(tests[i].x, &x); err != nil {
+			t.Fatalf("[%d] JSON err: %v", i+1, err)
+		}
+
+		_, typ, ok := ExtractGeoShapeCoordinates(x, tests[i].typ)
+		if ok != tests[i].expectOK {
+			t.Errorf("[%d] expected ok %t, got %t", i+1, tests[i].expectOK, ok)
+		}
+
+		if ok && typ != tests[i].typ {
+			t.Errorf("[%d] expected type %s, got %s", i+1, tests[i].typ, typ)
+		}
+	}
+}