[vpython] Verify environment, named installs.

vpython/spec/spec.go

 // Copyright 2017 The LUCI Authors. All rights reserved.
 // Use of this source code is governed under the Apache License, Version 2.0
 // that can be found in the LICENSE file.
 
 package spec
 
 import (
         "crypto/sha256"
         "encoding/hex"
         "fmt"
         "sort"
 
         "github.com/luci/luci-go/vpython/api/vpython"
 
         "github.com/luci/luci-go/common/data/sortby"
         "github.com/luci/luci-go/common/errors"
 
         "github.com/golang/protobuf/proto"
 )
 
 // Render creates a human-readable string from spec.
 func Render(spec *vpython.Spec) string { return proto.MarshalTextString(spec) }
 
-// Normalize normalizes the specification Message such that two messages
-// with identical meaning will have identical representation.
-func Normalize(spec *vpython.Spec, defaultVENVPackage *vpython.Spec_Package) error {
-        if spec.Virtualenv == nil {
-                spec.Virtualenv = defaultVENVPackage
+// NormalizeEnvironment normalizes the supplied Environment such that two
+// messages with identical meaning will have identical representation.
+func NormalizeEnvironment(env *vpython.Environment) error {
+        if env.Spec == nil {
+                env.Spec = &vpython.Spec{}
+        }
+        if err := NormalizeSpec(env.Spec); err != nil {
+                return err
         }
 
+        if env.Runtime == nil {
+                env.Runtime = &vpython.Runtime{}
+        }
+
+        sort.Sort(pep425TagSlice(env.Pep425Tag))
+        return nil
+}
+
+// NormalizeSpec normalizes the specification Message such that two messages
+// with identical meaning will have identical representation.
+func NormalizeSpec(spec *vpython.Spec) error {
         sort.Sort(specPackageSlice(spec.Wheel))
 
         // No duplicate packages. Since we're sorted, we can just check for no
         // immediate repetitions.
         for i, pkg := range spec.Wheel {
                 if i > 0 && pkg.Name == spec.Wheel[i-1].Name {
                         return errors.Reason("duplicate spec entries for package %(path)q").
                                 D("name", pkg.Name).
                                 Err()
                 }
@@ skipping 39 matching lines @@
 
 func (s specPackageSlice) Len() int      { return len(s) }
 func (s specPackageSlice) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
 
 func (s specPackageSlice) Less(i, j int) bool {
         return sortby.Chain{
                 func(i, j int) bool { return s[i].Name < s[j].Name },
                 func(i, j int) bool { return s[i].Version < s[j].Version },
         }.Use(i, j)
 }
+
+type pep425TagSlice []*vpython.Pep425Tag
+
+func (s pep425TagSlice) Len() int      { return len(s) }
+func (s pep425TagSlice) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
+
+func (s pep425TagSlice) Less(i, j int) bool {
+        return sortby.Chain{
+                func(i, j int) bool { return s[i].Version < s[j].Version },
+                func(i, j int) bool { return s[i].Abi < s[j].Abi },
+                func(i, j int) bool { return s[i].Arch < s[j].Arch },
+        }.Use(i, j)
+}