From ebd34e3e4500b3feef4b4f98526ae95172cd8088 Mon Sep 17 00:00:00 2001 From: Matthew Dempsky Date: Sun, 17 Jul 2022 19:53:19 -0700 Subject: [PATCH] [dev.unified] test: relax panic message expectations In this test, traditionally the comparison `*l == r[0]` was left as a comparison between `*l` (type `any`) and `r[0]` (type `*int`), and the rest of the compiler needed to handle mixed-typed comparisons. However, this means more complexity for wiring up explicit rtypes. To simplify rtype handling, the next CL will change unified IR to instead handle the expression as `*l == any(r[0])`. However, a consequence of this currently is that walk will now sequence the `any(r[0])` expression first, because it involves a concrete-to-interface conversion. And in turn, this means the `r[0]` panic ("index out of bounds") will take priority over the `*l` panic ("nil pointer dereference"). This is a change in user-visible semantics in some cases, but the Go spec leaves this unspecified, so it shouldn't be an issue. Note also: gccgo has the same behavior (i.e., panicking on index out of bounds, not nil pointer dereference), and cmd/compile also already has the same behavior when the interface conversion is explicit (as in the added "nil pointer dereference #3" test case). Updates #23735. Updates #32187. Change-Id: I49e5dcca85b4680f9c8780ef0013e64254d38fe5 Reviewed-on: https://go-review.googlesource.com/c/go/+/418097 Run-TryBot: Matthew Dempsky TryBot-Result: Gopher Robot Reviewed-by: Cuong Manh Le Reviewed-by: David Chase --- test/fixedbugs/issue32187.go | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/test/fixedbugs/issue32187.go b/test/fixedbugs/issue32187.go index 9c8c9c26d7980..268da8112ff8f 100644 --- a/test/fixedbugs/issue32187.go +++ b/test/fixedbugs/issue32187.go @@ -36,7 +36,11 @@ func main() { {"type assertion", "", func() { _ = x == x.(*int) }}, {"out of bounds", "", func() { _ = x == s[1] }}, {"nil pointer dereference #1", "", func() { _ = x == *p }}, - {"nil pointer dereference #2", "nil pointer dereference", func() { _ = *l == r[0] }}, + // TODO(mdempsky): Restore "nil pointer dereference" check. The Go + // spec doesn't mandate an order for panics (or even panic + // messages), but left-to-right is less confusing to users. + {"nil pointer dereference #2", "", func() { _ = *l == r[0] }}, + {"nil pointer dereference #3", "", func() { _ = *l == any(r[0]) }}, } for _, tc := range tests { @@ -44,16 +48,14 @@ func main() { } } -func testFuncShouldPanic(name, errStr string, f func()) { +func testFuncShouldPanic(name, want string, f func()) { defer func() { e := recover() if e == nil { log.Fatalf("%s: comparison did not panic\n", name) } - if errStr != "" { - if !strings.Contains(e.(error).Error(), errStr) { - log.Fatalf("%s: wrong panic message\n", name) - } + if have := e.(error).Error(); !strings.Contains(have, want) { + log.Fatalf("%s: wrong panic message: have %q, want %q\n", name, have, want) } }() f()