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cmd/compile, reflect: StructField.PkgPath is not correctly set for unnamed struct fields #15026

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kylelemons opened this issue Mar 30, 2016 · 1 comment
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cmd/compile, reflect: StructField.PkgPath is not correctly set for unnamed struct fields #15026

kylelemons opened this issue Mar 30, 2016 · 1 comment
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Go1.7

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@kylelemons
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  1. What version of Go are you using (go version)?
    go version devel +897dcdb Wed Mar 30 06:56:25 2016 +0000 linux/amd64
  2. What operating system and processor architecture are you using (go env)?
    linux/amd64

This is a regression at tip. Here is a short repro:

kyle@eros-ubuntu-vm /tmp/go $ cat reflect_test.go
package foo

import (
        "reflect"
        "testing"
)

func TestReflect(t *testing.T) {
        typ := reflect.TypeOf(struct{ Exported, unexported string }{})
        for _, test := range []struct {
                index          int
                field, pkgPath string
        }{
                {0, "Exported", ""},
                {1, "unexported", "_/tmp/go"},
        } {
                f := typ.Field(test.index)
                if got, want := f.PkgPath, test.pkgPath; got != want {
                        t.Errorf("Field(%d) (%q).PkgPath = %q, want %q", test.index, test.field, got, want)
                } else {
                        t.Logf("Field(%d) (%q).PkgPath = %q [OK]", test.index, test.field, f.PkgPath)
                }
        }
}

Here is the behavior at head:

kyle@eros-ubuntu-vm /tmp/go $ go version
go version go1.6 linux/amd64
kyle@eros-ubuntu-vm /tmp/go $ go test -test.v .
=== RUN   TestReflect
--- PASS: TestReflect (0.00s)
        reflect_test.go:25: Field(0) ("Exported").PkgPath = "" [OK]
        reflect_test.go:25: Field(1) ("unexported").PkgPath = "_/tmp/go" [OK]
PASS
ok      _/tmp/go        0.002s

(notice that the unexported field has a non-zero PkgPath)

Here is the behavior at tip:

kyle@eros-ubuntu-vm /tmp/go $ ~/gotip/bin/go version
go version devel +897dcdb Wed Mar 30 06:56:25 2016 +0000 linux/amd64
kyle@eros-ubuntu-vm /tmp/go $ ~/gotip/bin/go test -test.v .
=== RUN   TestReflect
--- FAIL: TestReflect (0.00s)
        reflect_test.go:25: Field(0) ("Exported").PkgPath = "" [OK]
        reflect_test.go:23: Field(1) ("unexported").PkgPath = "", want "_/tmp/go"
FAIL
exit status 1
FAIL    _/tmp/go        0.001s

(notice that the unexported field has a zero PkgPath)

It works fine for named structs even at tip. So far a quick skim of the changes to the reflect library didn't turn up any likely suspects, though there are quite a number of them.
@ianlancetaylor ianlancetaylor changed the title [reflect] StructField.PkgPath is not correctly set for unnamed struct fields cmd/compile, reflect: StructField.PkgPath is not correctly set for unnamed struct fields Mar 30, 2016
@ianlancetaylor ianlancetaylor added this to the Go1.7 milestone Mar 30, 2016
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CL https://golang.org/cl/21286 mentions this issue.

wheelcomplex pushed a commit to wheelcomplex/smith-go that referenced this issue Aug 31, 2016
runtime: use cpuset_getaffinity for runtime.NumCPU() on FreeBSD
5efc22d 
In FreeBSD when run Go proc under a given sub-list of processors(e.g. 'cpuset -l 0 ./goutil' in multicore system),
runtime.NumCPU() still return all actived CPUs instead of the number of sub-list.

Fix by use syscall cpuset_getaffinity to account the number of sub-list.

Fixes golang#15026

Tested on:
FreeBSD amd64 10/11/12
FreeBSD i386 10/11/12
FreeBSD arm 10/11/12

This is inspired by golang@4f308ed
(runtime: use sched_getaffinity for runtime.NumCPU() on Linux)
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@crawshaw @kylelemons @ianlancetaylor @gopherbot