From fc41995a47f9a94de3d8dba22095fba86279061c Mon Sep 17 00:00:00 2001
From: Dominik Schmidt <dev@dominik-schmidt.de>
Date: Mon, 10 Aug 2026 19:42:08 +0200
Subject: [PATCH] fix(search): validate CaseInsensitive against the effective
 field type

The guard only rejected CaseInsensitive when a non-keyword/path Type was set explicitly. With no Type, isCasedType treated the field as cased, so CaseInsensitive on an inferred numeric/bool/datetime field passed validation but produced no _lowercase sibling, and the query would silently match nothing. Validate now falls back to the inferred Go type.
---
 services/search/pkg/mapping/validate.go      | 33 ++++++++++++++------
 services/search/pkg/mapping/validate_test.go | 24 ++++++++++++++
 2 files changed, 48 insertions(+), 9 deletions(-)

diff --git a/services/search/pkg/mapping/validate.go b/services/search/pkg/mapping/validate.go
index f0a8e462e2..fa6a8b222e 100644
--- a/services/search/pkg/mapping/validate.go
+++ b/services/search/pkg/mapping/validate.go
@@ -16,17 +16,20 @@ func Validate(t reflect.Type, overrides map[string]FieldOpts) error {
 	if len(overrides) == 0 {
 		return nil
 	}
-	names := collectNames(t, "")
+	fields := collectFields(t, "")
 	var unknown, miscased []string
 	for k, opts := range overrides {
-		if _, ok := names[k]; !ok {
+		goType, ok := fields[k]
+		if !ok {
 			unknown = append(unknown, k)
 			continue
 		}
 		// CaseInsensitive routes queries to a <field>_lowercase sibling, which is
 		// only generated for keyword/path fields; on any other type the query
-		// would target a non-existent field and silently match nothing.
-		if opts.caseInsensitive() && !isCasedType(opts) {
+		// would target a non-existent field and silently match nothing. Use the
+		// effective type (override, else the inferred Go type), since an override
+		// with no explicit Type still infers keyword/numeric/... from the field.
+		if opts.caseInsensitive() && !effectivelyCased(opts, goType) {
 			miscased = append(miscased, k)
 		}
 	}
@@ -41,17 +44,29 @@ func Validate(t reflect.Type, overrides map[string]FieldOpts) error {
 	return nil
 }
 
-func collectNames(t reflect.Type, prefix string) map[string]struct{} {
-	out := map[string]struct{}{}
+// effectivelyCased reports whether a field is keyword/path (the only types that
+// get a _lowercase sibling), from the override type or the inferred Go type.
+func effectivelyCased(opts FieldOpts, goType reflect.Type) bool {
+	eff := opts.Type
+	if eff == "" && goType != nil {
+		eff = inferType(goType)
+	}
+	return eff == TypeKeyword || eff == TypePath
+}
+
+// collectFields maps every known field name (nested as "parent.child") to its Go
+// type. Embedded structs are flattened, matching encoding/json.
+func collectFields(t reflect.Type, prefix string) map[string]reflect.Type {
+	out := map[string]reflect.Type{}
 	_ = walkFields(t, func(fi fieldInfo) error {
 		key := fi.Name
 		if prefix != "" {
 			key = prefix + "." + fi.Name
 		}
-		out[key] = struct{}{}
+		out[key] = fi.GoField.Type
 		if sub := structType(fi.GoField.Type); sub != nil {
-			for k := range collectNames(sub, key) {
-				out[k] = struct{}{}
+			for k, v := range collectFields(sub, key) {
+				out[k] = v
 			}
 		}
 		return nil
diff --git a/services/search/pkg/mapping/validate_test.go b/services/search/pkg/mapping/validate_test.go
index 69a96b0a01..7a34183a4b 100644
--- a/services/search/pkg/mapping/validate_test.go
+++ b/services/search/pkg/mapping/validate_test.go
@@ -54,4 +54,28 @@ var _ = Describe("Validate", func() {
 		Expect(err.Error()).To(ContainSubstring("Name"))
 		Expect(err.Error()).To(ContainSubstring("CaseInsensitive"))
 	})
+
+	It("rejects CaseInsensitive on an inferred non-keyword field (empty Type)", func() {
+		True := true
+		type doc struct {
+			Size uint64 `json:"Size"`
+		}
+		err := Validate(reflect.TypeFor[doc](), map[string]FieldOpts{
+			"Size": {CaseInsensitive: &True}, // no explicit Type -> inferred numeric
+		})
+		Expect(err).To(HaveOccurred())
+		Expect(err.Error()).To(ContainSubstring("Size"))
+	})
+
+	It("accepts CaseInsensitive on an inferred keyword field (empty Type)", func() {
+		True := true
+		type doc struct {
+			Name string   `json:"Name"`
+			Tags []string `json:"Tags"`
+		}
+		Expect(Validate(reflect.TypeFor[doc](), map[string]FieldOpts{
+			"Name": {CaseInsensitive: &True},
+			"Tags": {CaseInsensitive: &True},
+		})).To(Succeed())
+	})
 })