Fix crash in go_symbol_package_name

go_symbol_package_name package name asserts that it is only passed a
Go symbol, but this is not enforced by one caller.  It seems simplest
to just check and return early in this case.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=17876
Reviewed-By: Andrew Burgess <aburgess@redhat.com>

3 files changed, 34 insertions, 2 deletions

diff --git a/gdb/go-lang.c b/gdb/go-lang.c
index f9176ac..bbf80af 100644
--- a/gdb/go-lang.c
+++ b/gdb/go-lang.c
@@ -394,7 +394,8 @@ go_symbol_package_name (const struct symbol *sym)
   int method_type_is_pointer;
   gdb::unique_xmalloc_ptr<char> name_buf;
 
-  gdb_assert (sym->language () == language_go);
+  if (sym->language () != language_go)
+    return nullptr;
   name_buf = unpack_mangled_go_symbol (mangled_name,
 				       &package_name, &object_name,
 				       &method_type_package_name,
diff --git a/gdb/go-lang.h b/gdb/go-lang.h
index 3b1aa5c..0d7104b 100644
--- a/gdb/go-lang.h
+++ b/gdb/go-lang.h
@@ -63,7 +63,7 @@ extern const char *go_main_name (void);
 
 extern enum go_type go_classify_struct_type (struct type *type);
 
-/* Given a Go symbol, return its package or nullptr if unknown.  */
+/* Given a symbol, return its package or nullptr if unknown.  */
 extern gdb::unique_xmalloc_ptr<char> go_symbol_package_name
      (const struct symbol *sym);
 
diff --git a/gdb/testsuite/gdb.go/no-package.exp b/gdb/testsuite/gdb.go/no-package.exp
new file mode 100644
index 0000000..3b39bc3
--- /dev/null
+++ b/gdb/testsuite/gdb.go/no-package.exp
@@ -0,0 +1,31 @@
+# This testcase is part of GDB, the GNU debugger.
+
+# Copyright 2023 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Regression test for a crash in go_symbol_package_name.
+
+load_lib "go.exp"
+
+require allow_go_tests support_go_compile !use_gdb_stub
+
+standard_testfile integers.go
+
+if {[prepare_for_testing "failed to prepare" ${testfile} ${srcfile} {debug go}]} {
+    return -1
+}
+
+# The bug was that stopping in _start would crash.
+runto "*_start" message