feat: add build info retrieval and associated tests

cmd/buildinfo.go

@@ -0,0 +1,33 @@
+package cmd
+
+import "runtime/debug"
+
+func init() {
+	if version == "dev" {
+		applyBuildInfo()
+	}
+}
+
+// applyBuildInfo reads Go's embedded build metadata and populates the version,
+// commit, and buildDate vars when they were not injected via ldflags (e.g. go install).
+func applyBuildInfo() {
+	info, ok := debug.ReadBuildInfo()
+	if !ok {
+		return
+	}
+	if v := info.Main.Version; v != "" && v != "(devel)" {
+		version = v
+	}
+	for _, s := range info.Settings {
+		switch s.Key {
+		case "vcs.revision":
+			if s.Value != "" {
+				commit = s.Value
+			}
+		case "vcs.time":
+			if s.Value != "" {
+				buildDate = s.Value
+			}
+		}
+	}
+}

cmd/buildinfo_test.go

@@ -0,0 +1,28 @@
+package cmd
+
+import "testing"
+
+func TestApplyBuildInfoDoesNotPanic(t *testing.T) {
+	originalVersion := version
+	originalCommit := commit
+	originalBuildDate := buildDate
+	t.Cleanup(func() {
+		version = originalVersion
+		commit = originalCommit
+		buildDate = originalBuildDate
+	})
+
+	applyBuildInfo()
+}
+
+func TestApplyBuildInfoDoesNotSetDevilVersion(t *testing.T) {
+	originalVersion := version
+	t.Cleanup(func() { version = originalVersion })
+
+	version = "dev"
+	applyBuildInfo()
+
+	if version == "(devel)" {
+		t.Fatal("applyBuildInfo must not set version to '(devel)'")
+	}
+}