From 424970d23c722805151b8ae47182f8b2374c3fe7 Mon Sep 17 00:00:00 2001
From: Martin <martin@mdosch.de>
Date: Wed, 10 Jan 2024 15:49:08 +0100
Subject: [PATCH] Fix manual choice of auth mechanism. (#173)

---
 xmpp.go | 65 ++++++++++++++++++++++++++++++---------------------------
 1 file changed, 34 insertions(+), 31 deletions(-)

diff --git a/xmpp.go b/xmpp.go
index 6bf51c4..ac341a3 100644
--- a/xmpp.go
+++ b/xmpp.go
@@ -406,37 +406,40 @@ func (c *Client) init(o *Options) error {
 			tlsConnOK = true
 		}
 		mechanism = ""
-		switch {
-		case slices.Contains(f.Mechanisms.Mechanism,
-			o.Mechanism) && o.Mechanism != "":
-			mechanism = o.Mechanism
-		case slices.Contains(f.Mechanisms.Mechanism,
-			"SCRAM-SHA-512-PLUS") && tlsConnOK:
-			mechanism = "SCRAM-SHA-512-PLUS"
-		case slices.Contains(f.Mechanisms.Mechanism,
-			"SCRAM-SHA-256-PLUS") && tlsConnOK:
-			mechanism = "SCRAM-SHA-256-PLUS"
-		case slices.Contains(f.Mechanisms.Mechanism,
-			"SCRAM-SHA-1-PLUS") && tlsConnOK:
-			mechanism = "SCRAM-SHA-1-PLUS"
-		case slices.Contains(f.Mechanisms.Mechanism,
-			"SCRAM-SHA-512"):
-			mechanism = "SCRAM-SHA-512"
-		case slices.Contains(f.Mechanisms.Mechanism,
-			"SCRAM-SHA-256"):
-			mechanism = "SCRAM-SHA-256"
-		case slices.Contains(f.Mechanisms.Mechanism,
-			"SCRAM-SHA-1"):
-			mechanism = "SCRAM-SHA-1"
-		case slices.Contains(f.Mechanisms.Mechanism,
-			"X-OAUTH2"):
-			mechanism = "X-OAUTH2"
-		case slices.Contains(f.Mechanisms.Mechanism,
-			"PLAIN") && tlsConnOK:
-			mechanism = "PLAIN"
-		case slices.Contains(f.Mechanisms.Mechanism,
-			"DIGEST-MD5"):
-			mechanism = "DIGEST-MD5"
+		if o.Mechanism != "" {
+			if slices.Contains(f.Mechanisms.Mechanism, o.Mechanism) {
+				mechanism = o.Mechanism
+			}
+		} else {
+			switch {
+			case slices.Contains(f.Mechanisms.Mechanism,
+				"SCRAM-SHA-512-PLUS") && tlsConnOK:
+				mechanism = "SCRAM-SHA-512-PLUS"
+			case slices.Contains(f.Mechanisms.Mechanism,
+				"SCRAM-SHA-256-PLUS") && tlsConnOK:
+				mechanism = "SCRAM-SHA-256-PLUS"
+			case slices.Contains(f.Mechanisms.Mechanism,
+				"SCRAM-SHA-1-PLUS") && tlsConnOK:
+				mechanism = "SCRAM-SHA-1-PLUS"
+			case slices.Contains(f.Mechanisms.Mechanism,
+				"SCRAM-SHA-512"):
+				mechanism = "SCRAM-SHA-512"
+			case slices.Contains(f.Mechanisms.Mechanism,
+				"SCRAM-SHA-256"):
+				mechanism = "SCRAM-SHA-256"
+			case slices.Contains(f.Mechanisms.Mechanism,
+				"SCRAM-SHA-1"):
+				mechanism = "SCRAM-SHA-1"
+			case slices.Contains(f.Mechanisms.Mechanism,
+				"X-OAUTH2"):
+				mechanism = "X-OAUTH2"
+			case slices.Contains(f.Mechanisms.Mechanism,
+				"PLAIN") && tlsConnOK:
+				mechanism = "PLAIN"
+			case slices.Contains(f.Mechanisms.Mechanism,
+				"DIGEST-MD5"):
+				mechanism = "DIGEST-MD5"
+			}
 		}
 		if strings.HasPrefix(mechanism, "SCRAM-SHA") {
 			if strings.HasSuffix(mechanism, "PLUS") {