test(symdb): add fork behaviour test

ddtrace/internal/symbol_db/remoteconfig.py

@@ -19,7 +19,7 @@
 log = get_logger(__name__)
 
 
-def _rc_callback(data: t.List[Payload], test_tracer=None):
+def _rc_callback(data: t.Sequence[Payload]):
     if get_ancestor_runtime_id() is not None and has_forked():
         log.debug("[PID %d] SymDB: Disabling Symbol DB in forked process", os.getpid())
         # We assume that forking is being used for spawning child worker

tests/internal/symbol_db/test_symbols.py

@@ -286,3 +286,37 @@ def get_scope(contexts, name):
     scope = get_scope(contexts, "tests.submod.stuff")
     assert scope["scope_type"] == ScopeType.MODULE
     assert scope["name"] == "tests.submod.stuff"
+
+
+@pytest.mark.subprocess(ddtrace_run=True, err=None)
+def test_symbols_fork_uploads():
+    """
+    Test that we disable Symbol DB on processes that are not the main one nor
+    the first fork child.
+    """
+    import os
+
+    from ddtrace.internal import forksafe
+    from ddtrace.internal.remoteconfig import ConfigMetadata
+    from ddtrace.internal.remoteconfig import Payload
+    from ddtrace.internal.runtime import get_ancestor_runtime_id
+    from ddtrace.internal.symbol_db.remoteconfig import _rc_callback
+    from ddtrace.internal.symbol_db.symbols import SymbolDatabaseUploader
+
+    SymbolDatabaseUploader.install()
+
+    pids = []
+    rc_data = [Payload(ConfigMetadata("test", "symdb", "hash", 0, 0), "test", None)]
+
+    for _ in range(10):
+        if not (pid := os.fork()):
+            _rc_callback(rc_data)
+            assert SymbolDatabaseUploader.is_installed() != (
+                get_ancestor_runtime_id() is not None and forksafe.has_forked()
+            )
+            os._exit(0)
+
+        pids.append(pid)
+
+    for pid in pids:
+        os.waitpid(pid, 0)