Bump the string length limit to 255 characters

CHANGELOG.md

@@ -2,6 +2,9 @@
 
 [Full changelog](https://github.com/mozilla/glean/compare/v60.3.0...main)
 
+* General
+  * Bump the string length limit to 255 characters ([#2857](https://github.com/mozilla/glean/pull/2857))
+
 # v60.3.0 (2024-05-31)
 
 [Full changelog](https://github.com/mozilla/glean/compare/v60.2.0...v60.3.0)

docs/user/reference/metrics/string.md

@@ -121,7 +121,8 @@ Glean.searchDefault.name.set("wikipedia");
 
 #### Limits
 
-* Fixed maximum string length: 100. Longer strings are truncated. This is measured in the number of bytes when the string is encoded in UTF-8.
+* Fixed maximum string length: 255. Longer strings are truncated. This is measured in the number of bytes when the string is encoded in UTF-8.
+  * Prior to Glean v60.4.0 the limit was 100 bytes.
 
 ## Testing API
 

glean-core/android/src/test/java/mozilla/telemetry/glean/private/StringMetricTypeTest.kt

@@ -124,7 +124,7 @@ class StringMetricTypeTest {
             ),
         )
 
-        stringMetric.set("0123456789".repeat(11))
+        stringMetric.set("0123456789".repeat(26))
 
         assertEquals(1, stringMetric.testGetNumRecordedErrors(ErrorType.INVALID_OVERFLOW))
     }

glean-core/ios/GleanTests/Metrics/StringMetricTests.swift

@@ -88,7 +88,7 @@ class StringMetricTests: XCTestCase {
             disabled: false
         ))
 
-        stringMetric.set(String(repeating: "0123456789", count: 11))
+        stringMetric.set(String(repeating: "0123456789", count: 26))
 
         XCTAssertEqual(1, stringMetric.testGetNumRecordedErrors(.invalidOverflow))
     }

glean-core/python/tests/metrics/test_string.py

@@ -79,7 +79,7 @@ def test_setting_a_long_string_records_an_error():
         )
     )
 
-    string_metric.set("0123456789" * 11)
+    string_metric.set("0123456789" * 26)
 
     assert 1 == string_metric.test_get_num_recorded_errors(testing.ErrorType.INVALID_OVERFLOW)
 

glean-core/src/metrics/string.rs

@@ -13,7 +13,7 @@ use crate::util::truncate_string_at_boundary_with_error;
 use crate::CommonMetricData;
 use crate::Glean;
 
-const MAX_LENGTH_VALUE: usize = 100;
+const MAX_LENGTH_VALUE: usize = 255;
 
 /// A string metric.
 ///
@@ -166,7 +166,7 @@ mod test {
             dynamic_label: None,
         });
 
-        let sample_string = "0123456789".repeat(11);
+        let sample_string = "0123456789".repeat(26);
         metric.set_sync(&glean, sample_string.clone());
 
         let truncated = truncate_string_at_boundary(sample_string, MAX_LENGTH_VALUE);

glean-core/tests/labeled.rs

@@ -162,7 +162,7 @@ fn can_record_error_for_submetric() {
     );
 
     let metric = labeled.get("label1");
-    metric.set_sync(&glean, "01234567890".repeat(20));
+    metric.set_sync(&glean, "01234567890".repeat(26));
 
     // Make sure that the errors have been recorded
     assert_eq!(

glean-core/tests/string.rs

@@ -104,12 +104,12 @@ fn long_string_values_are_truncated() {
         ..Default::default()
     });
 
-    let test_sting = "01234567890".repeat(20);
-    metric.set_sync(&glean, test_sting.clone());
+    let test_string = "01234567890".repeat(26);
+    metric.set_sync(&glean, test_string.clone());
 
     // Check that data was truncated
     assert_eq!(
-        test_sting[..100],
+        test_string[..255],
         metric.get_value(&glean, "store1").unwrap()
     );