From ca5774a5a533ce26ed64010fcc98f258e5bb0cc1 Mon Sep 17 00:00:00 2001 From: Jay Conrod Date: Thu, 14 Jan 2021 13:04:17 -0500 Subject: [PATCH] embed: treat uninitialized FS as empty As described in the FS documentation. This prevents http.FS and other clients from panicking when the go:embed directive is missing. For #43682 Related #43698 Change-Id: Iecf26d229a099e55d24670c3119cd6c6d17ecc6e Reviewed-on: https://go-review.googlesource.com/c/go/+/283852 Run-TryBot: Jay Conrod TryBot-Result: Go Bot Trust: Jay Conrod Reviewed-by: Bryan C. Mills --- src/embed/embed.go | 6 ++++++ src/embed/internal/embedtest/embed_test.go | 17 +++++++++++++++++ 2 files changed, 23 insertions(+) diff --git a/src/embed/embed.go b/src/embed/embed.go index 29e0adf1a63d1d..cc6855e6a5b0cc 100644 --- a/src/embed/embed.go +++ b/src/embed/embed.go @@ -244,6 +244,9 @@ func (f FS) lookup(name string) *file { if name == "." { return dotFile } + if f.files == nil { + return nil + } // Binary search to find where name would be in the list, // and then check if name is at that position. @@ -261,6 +264,9 @@ func (f FS) lookup(name string) *file { // readDir returns the list of files corresponding to the directory dir. func (f FS) readDir(dir string) []file { + if f.files == nil { + return nil + } // Binary search to find where dir starts and ends in the list // and then return that slice of the list. files := *f.files diff --git a/src/embed/internal/embedtest/embed_test.go b/src/embed/internal/embedtest/embed_test.go index 40f65ffc3ff424..43ae5c7e0569c8 100644 --- a/src/embed/internal/embedtest/embed_test.go +++ b/src/embed/internal/embedtest/embed_test.go @@ -112,3 +112,20 @@ func TestHidden(t *testing.T) { testDir(t, star, "testdata/.hidden", "fortune.txt", "more/") // but not .more or _more } + +func TestUninitialized(t *testing.T) { + var uninitialized embed.FS + testDir(t, uninitialized, ".") + f, err := uninitialized.Open(".") + if err != nil { + t.Fatal(err) + } + defer f.Close() + fi, err := f.Stat() + if err != nil { + t.Fatal(err) + } + if !fi.IsDir() { + t.Errorf("in uninitialized embed.FS, . is not a directory") + } +}