specs-go: make Version a string literal

Version is initialized during package initialization, which happens on
every start of any program importing this package (for example, runc,
which re-executes itself on every container start and exec). Using
fmt.Sprintf for that takes about 4us and 5 allocations (2920
bytes).

Remove all this, making it a plain string literal. Kept as a variable
rather than a constant, since some users overwrite it, and changing it
to a constant would break them.

Add a test to make sure Version is in sync with the constants, and
update the release checklist accordingly.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

Author: kolyshkin

RELEASES.md

@@ -61,8 +61,8 @@ Releases usually follow a few steps:
     * [ ] delete the `(^M|^A|^D)` lines, `:%!grep -vE '(^M|^A|^D)'`
     * [ ] merge multi-commit PRs (so each line has a `(#num)` suffix)
     * [ ] drop hash and indent, `:'<,'> s/^\w*  /^I* /`
-  * [ ] a commit bumping `./specs-go/version.go` to next version and empty the `VersionDev` variable
-  * [ ] a commit adding back the "+dev" to `VersionDev`
+  * [ ] a commit bumping `./specs-go/version.go` to next version and empty the `VersionDev` variable (update `Version` accordingly)
+  * [ ] a commit adding back the "+dev" to `VersionDev` and `Version`
 * [ ] send email to <dev@opencontainers.org>
   * [ ] copy the exact commit hash for bumping the version from the pull-request (since master always stays as "-dev")
   * [ ] count the PRs since last release (that this version is tracking, in the cases of multiple branching), like `git log --pretty=oneline --no-merges --decorate $priorTag..$versionBumpCommit  | grep \(pr\/ | wc -l`

specs-go/version.go

@@ -1,7 +1,5 @@
 package specs
 
-import "fmt"
-
 const (
 	// VersionMajor is for an API incompatible changes
 	VersionMajor = 1
@@ -15,4 +13,4 @@ const (
 )
 
 // Version is the specification version that the package types support.
-var Version = fmt.Sprintf("%d.%d.%d%s", VersionMajor, VersionMinor, VersionPatch, VersionDev)
+var Version = "1.3.0+dev"

specs-go/version_test.go

@@ -0,0 +1,13 @@
+package specs
+
+import (
+	"strconv"
+	"testing"
+)
+
+func TestVersionSynced(t *testing.T) {
+	wantVer := strconv.Itoa(VersionMajor) + "." + strconv.Itoa(VersionMinor) + "." + strconv.Itoa(VersionPatch) + VersionDev
+	if Version != wantVer {
+		t.Fatalf("Version mismatch: got %q, want %q", Version, wantVer)
+	}
+}