go: internal/reflectlite: Implements erroneously reports that map types do not implement interfaces

What version of Go are you using (`go version`)?

$ go version
go version go1.13 darwin/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (`go env`)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/james/Library/Caches/go-build"
GOENV="/Users/james/Library/Application Support/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GONOPROXY=""
GONOSUMDB=""
GOOS="darwin"
GOPATH="/Users/james/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/Cellar/go/1.13/libexec"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/Cellar/go/1.13/libexec/pkg/tool/darwin_amd64"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/Users/james/src/proglottis/ts/go.mod"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/nn/cm9pxx2x4pzcmc4_brdzc_9m0000gn/T/go-build569203332=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

Tried to check if an error was of type schema.MultiError.

https://play.golang.org/p/eAMul1kgxXJ

What did you expect to see?

Preferably it would populate my errMulti := schema.MultiError{} variable so I can inspect the contents for better error handling.

What did you see instead?

A runtime error:

runtime: nameOff 0x74696177 out of range 0xf0000 - 0x161ba6
fatal error: runtime: name offset out of range

About this issue

Original URL
State: closed
Created 5 years ago
Comments: 21 (16 by maintainers)

Commits related to this issue

runtime: add doc to remind adopting changes to reflectlite Updates #34486 Change-Id: Iec9a5d120013aaa287eccf2999b3f2b831be070e Reviewed-on: https://go-review.googlesource.com/c/go/+/197558 Reviewed-... — committed to golang/go by cuonglm 5 years ago
internal/reflectlite: add type mirror with reflect test Add test to check that struct type in reflectlite is mirror of reflect. Note that the test does not check the field types, only check for numbe... — committed to golang/go by cuonglm 5 years ago

Most upvoted comments

One thing that I noticed while looking at reflectlite is that we forgot to update it (we updated reflect) in https://golang.org/cl//191198 which likely causes mismatches of struct definitions between runtime and reflectlite.

Especially the map type is now larger: https://github.com/golang/go/blob/0f7b4e72a054f974489d8342cdae5a6a7ba7a31b/src/internal/reflectlite/type.go#L245 https://github.com/golang/go/blob/9c0e56bf9de5ff8faa73860ab6bb43562722c18f/src/runtime/type.go#L363

While at it we should add tests (to avoid misalignment and breakage of reflectlite) and update the comments to reference reflectlite for updates too.

Im happy work on a fix tomorrow evening UTC if no one jumps on realigning the definitions earlier.

martisch on Sep 26, 2019