refactor: improve binary version build string

Makefile

@@ -1,9 +1,5 @@
-VERSION ?= "$(shell git describe --tags --abbrev=0 | cut -c2-)"
-COMMIT_HASH ?= "$(shell git describe --long --dirty --always --match "" || true)"
-
 LDFLAGS ?= -s -w \
--X github.com/primevprotocol/mev-commit.version="$(VERSION)" \
--X github.com/primevprotocol/mev-commit.commitHash="$(COMMIT_HASH)"
+-X github.com/primevprotocol/mev-commit.version=$(shell git describe --tags)
 
 .PHONY: build
 build: export CGO_ENABLED=0

version.go

@@ -1,14 +1,78 @@
 package mevcommit
 
+import (
+	"runtime/debug"
+	"strings"
+)
+
 var (
-	version    string
-	commitHash string
+	// version will be the version git tag if the binary is built with
+	// the Makefile and the tag is set. If the tag does not exist the
+	// version will be set to "(devel)". If the binary is built some
+	// other way, it will be set to "unknown".
+	version = "unknown"
+
+	// revision is set from the vcs.revision tag in Go 1.18+.
+	revision = "unknown"
+
+	// dirtyBuild is set from the vcs.modified tag in Go 1.18+.
+	dirtyBuild = true
 )
 
-// Version returns the version of the binary.
+func init() {
+	info, ok := debug.ReadBuildInfo()
+	if !ok {
+		return
+	}
+	for _, kv := range info.Settings {
+		if kv.Value == "" {
+			continue
+		}
+		switch kv.Key {
+		case "vcs.revision":
+			revision = kv.Value
+		case "vcs.modified":
+			dirtyBuild = kv.Value == "true"
+		}
+	}
+
+}
+
+// Version returns the build version string of the binary in format:
+//
+//	<tag>-<commit-hash>[-dirty]
+//
+// If the tag is not set during build (the tag does not exist or the binary is
+// not build with the Makefile), the tag element will remain empty. If the
+// binary is built outside the vcs repository, the returned result will be
+// "devel". If the binary is built with the Makefile and the repository
+// is dirty, the -dirty element will be appended to the result.
+//
+// Examples:
+//
+//	"devel"
+//	"rev-333ab74"
+//	"rev-333ab74-dirty"
+//	"v1.0.0-rev-333ab74"
+//	"v1.0.0-rev-333ab74-dirty"
 func Version() string {
-	if version == "" || commitHash == "" {
-		return "dev-dirty"
+	parts := make([]string, 0, 3)
+	if version != "unknown" && version != "" {
+		parts = append(parts, version)
+	}
+	if revision != "unknown" && revision != "" {
+		parts = append(parts, "rev")
+		commit := revision
+		if len(commit) > 7 {
+			commit = commit[:7]
+		}
+		parts = append(parts, commit)
+		if dirtyBuild {
+			parts = append(parts, "dirty")
+		}
+	}
+	if len(parts) == 0 {
+		return "devel"
 	}
-	return version + "-" + commitHash
+	return strings.Join(parts, "-")
 }