cmd/go: update for go1 tag format

R=golang-dev, r, r
CC=golang-dev
https://golang.org/cl/5919048

diff --git a/src/cmd/go/get.go b/src/cmd/go/get.go
index c0788d30c6d6ee7d6824c197d0b634c29c283346..6ad683a8bec0894b3a5898617f826e7bcb0716e2 100644 (file)
--- a/src/cmd/go/get.go
+++ b/src/cmd/go/get.go
@@ -11,6 +11,7 @@ import (
        "go/build"
        "os"
        "path/filepath"
+       "regexp"
        "runtime"
        "strconv"
        "strings"
@@ -323,9 +324,18 @@ func downloadPackage(p *Package) error {
        return nil
 }
 
+// goTag matches go release tags such as go1 and go1.2.3.
+// The numbers involved must be small (at most 4 digits),
+// have no unnecessary leading zeros, and the version cannot
+// end in .0 - it is go1, not go1.0 or go1.0.0.
+var goTag = regexp.MustCompile(
+       `^go((0|[1-9][0-9]{0,3})\.)*([1-9][0-9]{0,3})$`,
+)
+
 // selectTag returns the closest matching tag for a given version.
 // Closest means the latest one that is not after the current release.
-// Version "release.rN" matches tags of the form "go.rN" (N being a decimal).
+// Version "goX" (or "goX.Y" or "goX.Y.Z") matches tags of the same form.
+// Version "release.rN" matches tags of the form "go.rN" (N being a floating-point number).
 // Version "weekly.YYYY-MM-DD" matches tags like "go.weekly.YYYY-MM-DD".
 func selectTag(goVersion string, tags []string) (match string) {
        const rPrefix = "release.r"
@@ -349,6 +359,7 @@ func selectTag(goVersion string, tags []string) (match string) {
                        }
                }
        }
+
        const wPrefix = "weekly."
        if strings.HasPrefix(goVersion, wPrefix) {
                p := "go.weekly."
@@ -362,5 +373,54 @@ func selectTag(goVersion string, tags []string) (match string) {
                        }
                }
        }
+
+       if goTag.MatchString(goVersion) {
+               v := goVersion
+               for _, t := range tags {
+                       if !goTag.MatchString(t) {
+                               continue
+                       }
+                       if cmpGoVersion(match, t) < 0 && cmpGoVersion(t, v) <= 0 {
+                               match = t
+                       }
+               }
+       }
+
        return match
 }
+
+// cmpGoVersion returns -1, 0, +1 reporting whether
+// x < y, x == y, or x > y.
+func cmpGoVersion(x, y string) int {
+       // Malformed strings compare less than well-formed strings.
+       if !goTag.MatchString(x) {
+               return -1
+       }
+       if !goTag.MatchString(y) {
+               return +1
+       }
+
+       // Compare numbers in sequence.
+       xx := strings.Split(x[len("go"):], ".")
+       yy := strings.Split(y[len("go"):], ".")
+
+       for i := 0; i < len(xx) && i < len(yy); i++ {
+               // The Atoi are guaranteed to succeed
+               // because the versions match goTag.
+               xi, _ := strconv.Atoi(xx[i])
+               yi, _ := strconv.Atoi(yy[i])
+               if xi < yi {
+                       return -1
+               } else if xi > yi {
+                       return +1
+               }
+       }
+
+       if len(xx) < len(yy) {
+               return -1
+       }
+       if len(xx) > len(yy) {
+               return +1
+       }
+       return 0
+}

diff --git a/src/cmd/go/tag_test.go b/src/cmd/go/tag_test.go
index a23a7ea82fdadcd782629edb91d61049409dc34a..556a84a8e42ce5fb1246c59e116a609925c45d31 100644 (file)
--- a/src/cmd/go/tag_test.go
+++ b/src/cmd/go/tag_test.go
@@ -18,6 +18,12 @@ var selectTagTestTags = []string{
        "go.weekly.2011-10-12.1",
        "go.weekly.2011-10-14",
        "go.weekly.2011-11-01",
+       "go1",
+       "go1.0.1",
+       "go1.999",
+       "go1.9.2",
+       "go5",
+
        // these should be ignored:
        "release.r59",
        "release.r59.1",
@@ -30,6 +36,14 @@ var selectTagTestTags = []string{
        "go.f00",
        "go!r60",
        "go.1999-01-01",
+       "go.2x",
+       "go.20000000000000",
+       "go.2.",
+       "go.2.0",
+       "go2x",
+       "go20000000000000",
+       "go2.",
+       "go2.0",
 }
 
 var selectTagTests = []struct {
@@ -56,11 +70,21 @@ var selectTagTests = []struct {
        {"weekly.2011-11-01", "go.weekly.2011-11-01"},
        {"weekly.2014-01-01", "go.weekly.2011-11-01"},
        {"weekly.3000-01-01", "go.weekly.2011-11-01"},
+       {"go1", "go1"},
+       {"go1.1", "go1.0.1"},
+       {"go1.998", "go1.9.2"},
+       {"go1.1000", "go1.999"},
+       {"go6", "go5"},
+
        // faulty versions:
        {"release.f00", ""},
        {"weekly.1999-01-01", ""},
        {"junk", ""},
        {"", ""},
+       {"go2x", ""},
+       {"go200000000000", ""},
+       {"go2.", ""},
+       {"go2.0", ""},
 }
 
 func TestSelectTag(t *testing.T) {

diff --git a/src/cmd/go/vcs.go b/src/cmd/go/vcs.go
index 3634b606c30dfb518d79659e82af99b9caf220f2..5f63f8b5683c9a63916f206b3fcbbb3f109627d6 100644 (file)
--- a/src/cmd/go/vcs.go
+++ b/src/cmd/go/vcs.go
@@ -71,7 +71,7 @@ var vcsHg = &vcsCmd{
 
        // We allow both tag and branch names as 'tags'
        // for selecting a version.  This lets people have
-       // a go.release.r60 branch and a go.1 branch
+       // a go.release.r60 branch and a go1 branch
        // and make changes in both, without constantly
        // editing .hgtags.
        tagCmd: []tagCmd{