Fix gitsign env test

pkg/version/version.go

@@ -29,6 +29,13 @@ var (
 	// Output of "git describe". The prerequisite is that the
 	// branch should be tagged using the correct versioning strategy.
 	gitVersion = "devel"
+
+	envVarPrefixes = []string{
+		"GITSIGN_",
+		// Can modify Sigstore/TUF client behavior - https://github.com/sigstore/sigstore/blob/35d6a82c15183f7fe7a07eca45e17e378aa32126/pkg/tuf/client.go#L52
+		"SIGSTORE_",
+		"TUF_",
+	}
 )
 
 type Info struct {
@@ -62,15 +69,15 @@ func getGitsignEnv() []string {
 	for _, e := range os.Environ() {
 		// Prefixes to look for. err on the side of showing too much rather
 		// than too little. We'll only output things that have values set.
-		for _, prefix := range []string{
-			"GITSIGN_",
-			// Can modify Sigstore/TUF client behavior - https://github.com/sigstore/sigstore/blob/35d6a82c15183f7fe7a07eca45e17e378aa32126/pkg/tuf/client.go#L52
-			"SIGSTORE_",
-			"TUF_",
-		} {
+		for _, prefix := range envVarPrefixes {
 			if strings.HasPrefix(e, prefix) {
+				eComponents := strings.Split(strings.TrimSpace(e), "=")
+				if len(eComponents) == 1 || len(eComponents[1]) == 0 {
+					// The variable is set to nothing
+					// eg: SIGSTORE_ROOT_FILE=
+					continue
+				}
 				out = append(out, e)
-				continue
 			}
 		}
 	}

pkg/version/version_test.go

@@ -17,6 +17,7 @@ package version
 
 import (
 	"os"
+	"strings"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -30,6 +31,15 @@ func TestVersionText(t *testing.T) {
 }
 
 func TestEnv(t *testing.T) {
+	for _, envVar := range os.Environ() {
+		for _, prefix := range envVarPrefixes {
+			if strings.HasPrefix(envVar, prefix) {
+				t.Setenv(strings.Split(envVar, "=")[0], "") // t.Setenv restores value during cleanup
+				break
+			}
+		}
+	}
+
 	os.Setenv("GITSIGN_CONNECTOR_ID", "foobar")
 	os.Setenv("GITSIGN_TEST", "foo")
 	os.Setenv("TUF_ROOT", "bar")
@@ -43,4 +53,12 @@ func TestEnv(t *testing.T) {
 	if diff := cmp.Diff(got.Env, want); diff != "" {
 		t.Error(diff)
 	}
+
+	// want doesn't change because the variable is set to nothing and must be
+	// ignored
+	os.Setenv("SIGSTORE_ROOT_FILE", "")
+	got = GetVersionInfo()
+	if diff := cmp.Diff(got.Env, want); diff != "" {
+		t.Error(diff)
+	}
 }