cmd/dist: delete special case for release branches without VERSION

findgoversion has some logic from before the go1 release that only
has effect when on a release branch without a VERSION file.

Starting with release-branch.go1 and the go1 tag a decade ago,
release branch have always had a VERSION file checked in.
(The commit that adds/updates the VERSION file is what is tagged.)

Since we have no need to support old branches like release-branch.r60,
and such scenarios don't come up in modern Go, delete it to simplify
this code a bit. Should the VERSION file situation change, we'd need
to rework this code anyway.

Fixes #42345.

Change-Id: I13f27babd37aaa5cec30fefde1b8e6ccce816461
Reviewed-on: https://go-review.googlesource.com/c/go/+/393954
Trust: Daniel Martí <mvdan@mvdan.cc>
Trust: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

diff --git a/src/cmd/dist/build.go b/src/cmd/dist/build.go
index 4dfaf83ef7f99bd6c9bf18cb43c3aa642c7e4e06..d224cef2a82c346afc94c98abf66f98df26575a1 100644 (file)
--- a/src/cmd/dist/build.go
+++ b/src/cmd/dist/build.go
@@ -316,34 +316,6 @@ func chomp(s string) string {
        return strings.TrimRight(s, " \t\r\n")
 }
 
-func branchtag(branch string) (tag string, precise bool) {
-       log := run(goroot, CheckExit, "git", "log", "--decorate=full", "--format=format:%d", "master.."+branch)
-       tag = branch
-       for row, line := range strings.Split(log, "\n") {
-               // Each line is either blank, or looks like
-               //        (tag: refs/tags/go1.4rc2, refs/remotes/origin/release-branch.go1.4, refs/heads/release-branch.go1.4)
-               // We need to find an element starting with refs/tags/.
-               const s = " refs/tags/"
-               i := strings.Index(line, s)
-               if i < 0 {
-                       continue
-               }
-               // Trim off known prefix.
-               line = line[i+len(s):]
-               // The tag name ends at a comma or paren.
-               j := strings.IndexAny(line, ",)")
-               if j < 0 {
-                       continue // malformed line; ignore it
-               }
-               tag = line[:j]
-               if row == 0 {
-                       precise = true // tag denotes HEAD
-               }
-               break
-       }
-       return
-}
-
 // findgoversion determines the Go version to use in the version string.
 func findgoversion() string {
        // The $GOROOT/VERSION file takes priority, for distributions
@@ -395,42 +367,26 @@ func findgoversion() string {
        }
 
        // Otherwise, use Git.
-       // What is the current branch?
-       branch := chomp(run(goroot, CheckExit, "git", "rev-parse", "--abbrev-ref", "HEAD"))
-
-       // What are the tags along the current branch?
-       tag := "devel"
-       precise := false
-
-       // If we're on a release branch, use the closest matching tag
-       // that is on the release branch (and not on the master branch).
-       if strings.HasPrefix(branch, "release-branch.") {
-               tag, precise = branchtag(branch)
-       }
-
-       if !precise {
-               // Tag does not point at HEAD; add 1.x base version, hash, and date to version.
-               //
-               // Note that we lightly parse internal/goversion/goversion.go to
-               // obtain the base version. We can't just import the package,
-               // because cmd/dist is built with a bootstrap GOROOT which could
-               // be an entirely different version of Go, like 1.4. We assume
-               // that the file contains "const Version = <Integer>".
-
-               goversionSource := readfile(pathf("%s/src/internal/goversion/goversion.go", goroot))
-               m := regexp.MustCompile(`(?m)^const Version = (\d+)`).FindStringSubmatch(goversionSource)
-               if m == nil {
-                       fatalf("internal/goversion/goversion.go does not contain 'const Version = ...'")
-               }
-               tag += fmt.Sprintf(" go1.%s-", m[1])
-
-               tag += chomp(run(goroot, CheckExit, "git", "log", "-n", "1", "--format=format:%h %cd", "HEAD"))
-       }
+       //
+       // Include 1.x base version, hash, and date in the version.
+       //
+       // Note that we lightly parse internal/goversion/goversion.go to
+       // obtain the base version. We can't just import the package,
+       // because cmd/dist is built with a bootstrap GOROOT which could
+       // be an entirely different version of Go, like 1.4. We assume
+       // that the file contains "const Version = <Integer>".
+       goversionSource := readfile(pathf("%s/src/internal/goversion/goversion.go", goroot))
+       m := regexp.MustCompile(`(?m)^const Version = (\d+)`).FindStringSubmatch(goversionSource)
+       if m == nil {
+               fatalf("internal/goversion/goversion.go does not contain 'const Version = ...'")
+       }
+       version := fmt.Sprintf("devel go1.%s-", m[1])
+       version += chomp(run(goroot, CheckExit, "git", "log", "-n", "1", "--format=format:%h %cd", "HEAD"))
 
        // Cache version.
-       writefile(tag, path, 0)
+       writefile(version, path, 0)
 
-       return tag
+       return version
 }
 
 // isGitRepo reports whether the working directory is inside a Git repository.