fix: Build routing header params map with the last entry if multiple entries have the same key. (#1729)

fixes: #1728 Guava ImmutableMap.Builder.build() will error out instead of replacing with the last entry if there are multiple entries with the same key, use `buildKeepingLast` instead of `build` to fix this issue.

Author: blakeli0

gax/src/main/java/com/google/api/gax/rpc/RequestParamsBuilder.java

@@ -73,6 +73,6 @@ public void add(String fieldValue, String headerKey, PathTemplate pathTemplate)
  }
 
  public Map<String, String> build() {
- return paramsBuilder.build();
+ return paramsBuilder.buildKeepingLast();
  }
 }

gax/src/test/java/com/google/api/gax/rpc/RequestParamsBuilderTest.java

@@ -51,42 +51,61 @@ public void setUp() {
 
  @Test
  public void add_happyPath() {
- String headerKey = "table_location";
  Map<String, String> actual =
  getRoutingHeaders(
- headerKey,
  "projects/**/{table_location=instances/*}",
  "projects/my_cozy_home/instances/living_room");
- assertThat(actual).containsExactly(headerKey, "instances/living_room");
+ assertThat(actual).containsExactly("table_location", "instances/living_room");
+ }
+
+ @Test
+ public void build_shouldKeepLastEntryIfMultipleEntriesHaveTheSameKeyRatherThanErrorOut() {
+ requestParamsBuilder.add(
+ "projects/my_cozy_home/instances/living_room",
+ "table_location",
+ PathTemplate.create("projects/**/{table_location=instances/*}"));
+ requestParamsBuilder.add(
+ "projects/my_cozy_home/instances/living_room",
+ "table_location",
+ PathTemplate.create("{table_location=**}"));
+ requestParamsBuilder.add(
+ "projects/my_cozy_home/instances/living_room",
+ "routing_id",
+ PathTemplate.create("{routing_id=**}"));
+ Map<String, String> actual = requestParamsBuilder.build();
+
+ // Should contain two entries instead of three, also should only keep the last entry if there
+ // are multiple entries with the same key
+ assertThat(actual)
+ .containsExactly(
+ "table_location",
+ "projects/my_cozy_home/instances/living_room",
+ "routing_id",
+ "projects/my_cozy_home/instances/living_room");
  }
 
  @Test
  public void add_matchedValuesWithNoRoutingHeaderKey() {
- Map<String, String> actual =
- getRoutingHeaders("table_location", "projects/**", "projects/my_cozy_home/");
+ Map<String, String> actual = getRoutingHeaders("projects/**", "projects/my_cozy_home/");
  assertThat(actual).isEmpty();
  }
 
  @Test
  public void add_emptyMatchedValues() {
  Map<String, String> actual =
- getRoutingHeaders(
- "table_location",
- "projects/**/{table_location=instances/*}",
- "projects/does_not_matter");
+ getRoutingHeaders("projects/**/{table_location=instances/*}", "projects/does_not_matter");
  assertThat(actual).isEmpty();
  }
 
  @Test
  public void add_nullFieldValue() {
- Map<String, String> actual = getRoutingHeaders("table_location", "projects/**", null);
+ Map<String, String> actual = getRoutingHeaders("projects/**", null);
  assertThat(actual).isEmpty();
  }
 
- private Map<String, String> getRoutingHeaders(
- String headerKey, String patternString, String fieldValue) {
+ private Map<String, String> getRoutingHeaders(String patternString, String fieldValue) {
  PathTemplate pathTemplate = PathTemplate.create(patternString);
- requestParamsBuilder.add(fieldValue, headerKey, pathTemplate);
+ requestParamsBuilder.add(fieldValue, "table_location", pathTemplate);
  return requestParamsBuilder.build();
  }
 }