Fix TraceState key validation limits to match W3C spec (#7575)

Author: priettt

api/all/src/main/java/io/opentelemetry/api/trace/ArrayBasedTraceStateBuilder.java

@@ -14,7 +14,7 @@
 
 final class ArrayBasedTraceStateBuilder implements TraceStateBuilder {
 
-  private static final int MAX_VENDOR_ID_SIZE = 13;
+  private static final int MAX_VENDOR_ID_SIZE = 14;
 
   // Needs to be in this class to avoid initialization deadlock because super class depends on
   // subclass (the auto-value generate class).
@@ -24,7 +24,7 @@ final class ArrayBasedTraceStateBuilder implements TraceStateBuilder {
   private static final int MAX_ENTRIES = 32;
   private static final int KEY_MAX_SIZE = 256;
   private static final int VALUE_MAX_SIZE = 256;
-  private static final int MAX_TENANT_ID_SIZE = 240;
+  private static final int MAX_TENANT_ID_SIZE = 241;
 
   // Later calls to put must be at the front of trace state. We append to the list and then reverse
   // when finished.
@@ -157,11 +157,11 @@ private static boolean isKeyValid(@Nullable String key) {
           return false;
         }
         isMultiTenantVendorKey = true;
-        // tenant id (the part to the left of the '@' sign) must be 240 characters or less
+        // tenant id (the part to the left of the '@' sign) must be 241 characters or less
         if (i > MAX_TENANT_ID_SIZE) {
           return false;
         }
-        // vendor id (the part to the right of the '@' sign) must be 1-13 characters long
+        // vendor id (the part to the right of the '@' sign) must be 1-14 characters long
         int remainingKeyChars = key.length() - i - 1;
         if (remainingKeyChars > MAX_VENDOR_ID_SIZE || remainingKeyChars == 0) {
           return false;

api/all/src/test/java/io/opentelemetry/api/trace/TraceStateTest.java

@@ -123,22 +123,39 @@ void testValidAtSignVendorNamePrefix() {
   }
 
   @Test
-  void testVendorIdLongerThan13Characters() {
-    assertThat(TraceState.builder().put("1@nrabcdefghijkl", FIRST_VALUE).build())
+  void testVendorIdWith14Characters() {
+    String key = "1@nrabcdefghijkl";
+    assertThat(TraceState.builder().put(key, FIRST_VALUE).build().get(key)).isEqualTo(FIRST_VALUE);
+  }
+
+  @Test
+  void testVendorIdLongerThan14Characters() {
+    assertThat(TraceState.builder().put("1@nrabcdefghijklm", FIRST_VALUE).build())
         .isEqualTo(TraceState.getDefault());
   }
 
   @Test
-  void testVendorIdLongerThan13Characters_longTenantId() {
-    assertThat(TraceState.builder().put("12345678901234567890@nrabcdefghijkl", FIRST_VALUE).build())
+  void testVendorIdLongerThan14Characters_longTenantId() {
+    assertThat(
+            TraceState.builder().put("12345678901234567890@nrabcdefghijklm", FIRST_VALUE).build())
         .isEqualTo(TraceState.getDefault());
   }
 
   @Test
-  void tenantIdLongerThan240Characters() {
+  void tenantIdWith241Characters() {
     char[] chars = new char[241];
     Arrays.fill(chars, 'a');
     String tenantId = new String(chars);
+    assertThat(
+            TraceState.builder().put(tenantId + "@nr", FIRST_VALUE).build().get(tenantId + "@nr"))
+        .isEqualTo(FIRST_VALUE);
+  }
+
+  @Test
+  void tenantIdLongerThan241Characters() {
+    char[] chars = new char[242];
+    Arrays.fill(chars, 'a');
+    String tenantId = new String(chars);
     assertThat(TraceState.builder().put(tenantId + "@nr", FIRST_VALUE).build())
         .isEqualTo(TraceState.getDefault());
   }