chore: normalize query param keys to lowercase in KeyRecipe

Author: rahul2393

google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/KeyRecipe.java

@@ -30,7 +30,10 @@
 import java.time.format.ResolverStyle;
 import java.util.ArrayList;
 import java.util.Base64;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Locale;
+import java.util.Map;
 import java.util.concurrent.ThreadLocalRandom;
 import java.util.function.BiFunction;
 import java.util.stream.Collectors;
@@ -780,10 +783,12 @@ public TargetRange keySetToTargetRange(KeySet in) {
   }
 
   public TargetRange queryParamsToTargetRange(Struct in) {
+    final Map<String, Value> lowercaseFields = new HashMap<>();
+    for (Map.Entry<String, Value> entry : in.getFieldsMap().entrySet()) {
+      lowercaseFields.put(entry.getKey().toLowerCase(Locale.ROOT), entry.getValue());
+    }
     return encodeKeyInternal(
-        (index, identifier) -> {
-          return in.getFieldsMap().get(identifier);
-        },
+        (index, identifier) -> lowercaseFields.get(identifier.toLowerCase(Locale.ROOT)),
         KeyType.FULL_KEY);
   }
 

google-cloud-spanner/src/test/java/com/google/cloud/spanner/spi/v1/KeyRecipeTest.java

@@ -17,6 +17,7 @@
 package com.google.cloud.spanner.spi.v1;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 import com.google.protobuf.ByteString;
@@ -76,6 +77,59 @@ public void queryParamsUsesConstantValue() throws Exception {
     assertTrue(target.limit.isEmpty());
   }
 
+  @Test
+  public void queryParamsCaseInsensitiveFallback() throws Exception {
+    com.google.spanner.v1.KeyRecipe recipeProto =
+        createRecipe(
+            "part { tag: 1 }\n"
+                + "part {\n"
+                + "  order: ASCENDING\n"
+                + "  null_order: NULLS_FIRST\n"
+                + "  type { code: STRING }\n"
+                + "  identifier: \"id\"\n"
+                + "}\n");
+
+    Struct params =
+        parseStruct(
+            "fields {\n" + "  key: \"Id\"\n" + "  value { string_value: \"foo\" }\n" + "}\n");
+
+    KeyRecipe recipe = KeyRecipe.create(recipeProto);
+    TargetRange target = recipe.queryParamsToTargetRange(params);
+    assertEquals(expectedKey("foo"), target.start);
+    assertTrue(target.limit.isEmpty());
+  }
+
+  @Test
+  public void queryParamsCaseInsensitiveDuplicateUsesLastValue() throws Exception {
+    com.google.spanner.v1.KeyRecipe recipeProto =
+        createRecipe(
+            "part { tag: 1 }\n"
+                + "part {\n"
+                + "  order: ASCENDING\n"
+                + "  null_order: NULLS_FIRST\n"
+                + "  type { code: STRING }\n"
+                + "  identifier: \"ID\"\n"
+                + "}\n");
+
+    // Both "Id" and "id" normalize to "id"; the last one ("id"→"bar") wins.
+    Struct params =
+        parseStruct(
+            "fields {\n"
+                + "  key: \"Id\"\n"
+                + "  value { string_value: \"foo\" }\n"
+                + "}\n"
+                + "fields {\n"
+                + "  key: \"id\"\n"
+                + "  value { string_value: \"bar\" }\n"
+                + "}\n");
+
+    KeyRecipe recipe = KeyRecipe.create(recipeProto);
+    TargetRange target = recipe.queryParamsToTargetRange(params);
+    assertEquals(expectedKey("bar"), target.start);
+    assertFalse(target.approximate);
+    assertTrue(target.limit.isEmpty());
+  }
+
   private static com.google.spanner.v1.KeyRecipe createRecipe(String text)
       throws TextFormat.ParseException {
     com.google.spanner.v1.KeyRecipe.Builder builder = com.google.spanner.v1.KeyRecipe.newBuilder();