extract sentry__ensure_user_id alongside sentry__ensure_event_id

Centralize the "user.id or installation_id" resolution so both the event
and session call sites share the same helper.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

Author: jpnurmi

src/sentry_core.c

@@ -856,6 +856,17 @@ sentry__ensure_event_id(sentry_value_t event, sentry_uuid_t *uuid_out)
     return event_id;
 }
 
+sentry_value_t
+sentry__ensure_user_id(sentry_value_t user, const char *installation_id)
+{
+    sentry_value_t user_id = sentry_value_get_by_key(user, "id");
+    if (sentry_value_is_null(user_id) && installation_id) {
+        user_id = sentry_value_new_string(installation_id);
+        sentry_value_set_by_key(user, "id", user_id);
+    }
+    return user_id;
+}
+
 void
 sentry_set_user(sentry_value_t user)
 {

src/sentry_core.h

@@ -109,6 +109,14 @@ sentry_uuid_t sentry__new_event_id(void);
 sentry_value_t sentry__ensure_event_id(
     sentry_value_t event, sentry_uuid_t *uuid_out);
 
+/**
+ * This will ensure that the given `user` has an `id`, falling back to
+ * `installation_id` when the user has no explicit id. Returns the id value
+ * (existing or newly-set), or a null value if neither is available.
+ */
+sentry_value_t sentry__ensure_user_id(
+    sentry_value_t user, const char *installation_id);
+
 /**
  * This will return an owned reference to the global options.
  */

src/sentry_scope.c

@@ -360,12 +360,9 @@ sentry__scope_apply_to_event(const sentry_scope_t *scope,
             if (IS_NULL("user")) {
                 SET("user", sentry__value_clone(scope->user));
             }
-            // patch missing user ID with installation ID
             sentry_value_t user = sentry_value_get_by_key(event, "user");
-            if (sentry_value_get_type(user) == SENTRY_VALUE_TYPE_OBJECT
-                && sentry_value_is_null(sentry_value_get_by_key(user, "id"))) {
-                sentry_value_set_by_key(user, "id",
-                    sentry_value_new_string(options->run->installation_id));
+            if (sentry_value_get_type(user) == SENTRY_VALUE_TYPE_OBJECT) {
+                sentry__ensure_user_id(user, options->run->installation_id);
             }
         } else if (sentry_value_get_length(scope->user) > 0) {
             PLACE_VALUE("user", scope->user);

src/sentry_session.c

@@ -1,5 +1,6 @@
 #include "sentry_session.h"
 #include "sentry_alloc.h"
+#include "sentry_core.h"
 #include "sentry_database.h"
 #include "sentry_envelope.h"
 #include "sentry_json.h"
@@ -301,12 +302,8 @@ void
 sentry__session_sync_user(
     sentry_session_t *session, sentry_value_t user, const char *installation_id)
 {
-    sentry_value_t did = sentry_value_get_by_key(user, "id");
+    sentry_value_t did = sentry__ensure_user_id(user, installation_id);
     sentry_value_decref(session->distinct_id);
-    if (sentry_value_is_null(did) && installation_id) {
-        session->distinct_id = sentry_value_new_string(installation_id);
-    } else {
-        sentry_value_incref(did);
-        session->distinct_id = did;
-    }
+    sentry_value_incref(did);
+    session->distinct_id = did;
 }