From a776087ee3b5780975b51db6a5d66cb7be7c50d4 Mon Sep 17 00:00:00 2001 From: Joe Tsai Date: Fri, 30 Jun 2017 15:44:25 -0700 Subject: [PATCH] runtime: allow calling Func.Name on nil pointer The Func type has allowed calling the Func.Name method on a nil pointer since Go1.2, where it returned an empty string. A regression caused by CL/37331 caused this behavior to change. This breaks code that lazily does runtime.FuncForPC(myPtr).Name() without first checking that myPtr is actually non-nil. Fixes #20872 Change-Id: Iae9a2ebabca5e9d1f5a2cdaf2f30e9c6198fec4f Reviewed-on: https://go-review.googlesource.com/47354 Reviewed-by: Marvin Stenger Reviewed-by: Brad Fitzpatrick --- src/runtime/symtab.go | 3 +++ src/runtime/symtab_test.go | 11 +++++++++++ 2 files changed, 14 insertions(+) diff --git a/src/runtime/symtab.go b/src/runtime/symtab.go index 029c2f15af..40add013e4 100644 --- a/src/runtime/symtab.go +++ b/src/runtime/symtab.go @@ -579,6 +579,9 @@ func FuncForPC(pc uintptr) *Func { // Name returns the name of the function. func (f *Func) Name() string { + if f == nil { + return "" + } return funcname(f.funcInfo()) } diff --git a/src/runtime/symtab_test.go b/src/runtime/symtab_test.go index b75b6b2c2a..01e5002659 100644 --- a/src/runtime/symtab_test.go +++ b/src/runtime/symtab_test.go @@ -154,3 +154,14 @@ func TestLineNumber(t *testing.T) { } } } + +func TestNilName(t *testing.T) { + defer func() { + if ex := recover(); ex != nil { + t.Fatalf("expected no nil panic, got=%v", ex) + } + }() + if got := (*runtime.Func)(nil).Name(); got != "" { + t.Errorf("Name() = %q, want %q", got, "") + } +}