fix: return error for empty Redis URL list (#3101)

* fix: return error for empty Redis URL list

* add changelog entry

Signed-off-by: Jan Larwig <jan@larwig.com>

---------

Signed-off-by: Jan Larwig <jan@larwig.com>
Co-authored-by: Jan Larwig <jan@larwig.com>

CHANGELOG.md

@@ -11,6 +11,7 @@
 - [#3072](https://github.com/oauth2-proxy/oauth2-proxy/pull/3072) feat: support for multiple github orgs #3072 (@daniel-mersch)
 - [#3116](https://github.com/oauth2-proxy/oauth2-proxy/pull/3116) feat: bump to go1.24.5 and full dependency update (@wardviaene / @dolmen)
 - [#3097](https://github.com/oauth2-proxy/oauth2-proxy/pull/3097) chore(deps): update alpine base image to v3.22.0
+- [#3101](https://github.com/oauth2-proxy/oauth2-proxy/pull/3101) fix: return error for empty Redis URL list (@dgivens)
 
 # V7.9.0
 

pkg/sessions/redis/redis_store.go

@@ -218,6 +218,10 @@ func setupTLSConfig(opts options.RedisStoreOptions, opt *redis.Options) error {
 // parseRedisURLs parses a list of redis urls and returns a list
 // of addresses in the form of host:port and redis.Options that can be used to connect to Redis
 func parseRedisURLs(urls []string) ([]string, *redis.Options, error) {
+	if len(urls) == 0 {
+		return nil, nil, fmt.Errorf("unable to parse redis urls: no redis urls provided")
+	}
+
 	addrs := []string{}
 	var redisOptions *redis.Options
 	for _, u := range urls {

pkg/sessions/redis/redis_store_test.go

@@ -19,6 +19,7 @@ const (
 )
 
 var _ = Describe("Redis SessionStore Tests", func() {
+	Describe("Redis SessionStore Creation", func() {
 		// helper interface to allow us to close client connections
 		// All non-nil redis clients should implement this
 		type closer interface {
@@ -243,3 +244,31 @@ var _ = Describe("Redis SessionStore Tests", func() {
 			})
 		})
 	})
+
+	Describe("Redis URL Parsing", func() {
+		It("should parse valid redis URL", func() {
+			addrs, opts, err := parseRedisURLs([]string{"redis://localhost:6379"})
+			Expect(err).ToNot(HaveOccurred())
+			Expect(addrs).To(Equal([]string{"localhost:6379"}))
+			Expect(opts).ToNot(BeNil())
+			Expect(opts.Addr).To(Equal("localhost:6379"))
+		})
+
+		It("should return error for invalid redis URL", func() {
+			addrs, opts, err := parseRedisURLs([]string{"invalid://url"})
+			Expect(err).To(HaveOccurred())
+			Expect(err.Error()).To(ContainSubstring("unable to parse redis url"))
+			Expect(err.Error()).To(Not(ContainSubstring("no redis urls provided")))
+			Expect(addrs).To(BeNil())
+			Expect(opts).To(BeNil())
+		})
+
+		It("should return error when no URLs provided", func() {
+			addrs, opts, err := parseRedisURLs([]string{})
+			Expect(err).To(HaveOccurred())
+			Expect(err.Error()).To(Equal("unable to parse redis urls: no redis urls provided"))
+			Expect(addrs).To(BeNil())
+			Expect(opts).To(BeNil())
+		})
+	})
+})