Bug 1649925 - Ensure Glean does not initialize with an empty application id

CHANGELOG.md

@@ -3,6 +3,7 @@
 * General
     * Remove locale from baseline ping. ([1609968](https://bugzilla.mozilla.org/show_bug.cgi?id=1609968), [#1016](https://github.com/mozilla/glean/pull/1016))
     * Persist X-Debug-ID header on store ping. ([1605097](https://bugzilla.mozilla.org/show_bug.cgi?id=1605097), [#1042](https://github.com/mozilla/glean/pull/1042))
+    * BUGFIX: raise an error if Glean is initialized with an empty string as the `application_id`.
 * Python
     * BUGFIX: correctly set the `app_build` metric to the newly provided `application_build_id` initialization option.
 

glean-core/src/error.rs

@@ -54,6 +54,9 @@ pub enum ErrorKind {
     /// Unknown error
     Utf8Error,
 
+    /// Glean initialization was attempted with an invalid configuration
+    InvalidConfig,
+
     /// Glean not initialized
     NotInitialized,
 
@@ -103,6 +106,7 @@ impl Display for Error {
             HistogramType(h) => write!(f, "HistogramType conversion from {} failed", h),
             OsString(s) => write!(f, "OsString conversion from {:?} failed", s),
             Utf8Error => write!(f, "Invalid UTF-8 byte sequence in string"),
+            InvalidConfig => write!(f, "Invalid Glean configuration provided"),
             NotInitialized => write!(f, "Global Glean object missing"),
             __NonExhaustive => write!(f, "Unknown error"),
         }

glean-core/src/lib.rs

@@ -42,7 +42,7 @@ mod util;
 
 pub use crate::common_metric_data::{CommonMetricData, Lifetime};
 use crate::database::Database;
-pub use crate::error::{Error, Result};
+pub use crate::error::{Error, ErrorKind, Result};
 pub use crate::error_recording::{test_get_num_recorded_errors, ErrorType};
 use crate::event_database::EventDatabase;
 use crate::internal_metrics::CoreMetrics;
@@ -188,6 +188,9 @@ impl Glean {
         log::info!("Creating new Glean v{}", GLEAN_VERSION);
 
         let application_id = sanitize_application_id(&cfg.application_id);
+        if application_id.is_empty() {
+            return Err(ErrorKind::InvalidConfig.into());
+        }
 
         // Creating the data store creates the necessary path as well.
         // If that fails we bail out and don't initialize further.

glean-core/src/lib_unit_tests.rs

@@ -778,3 +778,14 @@ fn test_setting_debug_view_tag() {
     assert_eq!(false, glean.set_debug_view_tag(invalid_tag));
     assert_eq!(valid_tag, glean.debug_view_tag().unwrap());
 }
+
+#[test]
+#[should_panic]
+fn test_empty_application_id() {
+    let dir = tempfile::tempdir().unwrap();
+    let tmpname = dir.path().display().to_string();
+
+    let glean = Glean::with_options(&tmpname, "", true).unwrap();
+    // Check that this is indeed the first run.
+    assert!(glean.is_first_run());
+}