From a8b31b82a35a442a48355f8619f9eb8fe3ffe77a Mon Sep 17 00:00:00 2001
From: ntoofu <ntoofu@users.noreply.github.com>
Date: Tue, 7 Apr 2026 01:35:49 +0000
Subject: [PATCH] feat: enhance parseRemoteAuthority to handle domains
 containing "--"

---
 src/util.ts            | 24 ++++++++++++++++++++----
 test/unit/util.test.ts | 11 +++++++++++
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/src/util.ts b/src/util.ts
index f9aa549d..b8223d0d 100644
--- a/src/util.ts
+++ b/src/util.ts
@@ -61,15 +61,31 @@ export function parseRemoteAuthority(authority: string): AuthorityParts | null {
 	// coder-vscode(--|.)<username>--<workspace>(--|.)<agent?>
 	// The agent can be omitted; the user will be prompted for it instead.
 	// Anything else is unrelated to Coder and can be ignored.
-	const parts = authorityParts[1].split("--");
+	const rawParts = authorityParts[1].split("--");
 	if (
-		parts.length <= 1 ||
-		(parts[0] !== AuthorityPrefix &&
-			!parts[0].startsWith(`${AuthorityPrefix}.`))
+		rawParts.length <= 1 ||
+		(rawParts[0] !== AuthorityPrefix &&
+			!rawParts[0].startsWith(`${AuthorityPrefix}.`))
 	) {
 		return null;
 	}
 
+	// DNS labels may legally contain "--" (Punycode labels like "xn--{encoded}"
+	// are a common example), which breaks a naive split.  Coder usernames and
+	// workspace names follow a slug pattern that never contains dots, so a
+	// dot-bearing segment after splitting on "--" must be a hostname fragment
+	// rather than a username.  We reassemble from the front: while the next
+	// segment contains a dot, merge it back into the accumulated prefix.
+	let reassemblingParts = rawParts;
+	while (reassemblingParts.length >= 2) {
+		if (reassemblingParts[1].includes(".")) {
+			reassemblingParts = [reassemblingParts.slice(0, 2).join("--"), ...reassemblingParts.slice(2)];
+		} else {
+			break;
+		}
+	}
+	const parts = reassemblingParts;
+
 	// It has the proper prefix, so this is probably a Coder host name.
 	// Validate the SSH host name.  Including the prefix, we expect at least
 	// three parts, or four if including the agent.
diff --git a/test/unit/util.test.ts b/test/unit/util.test.ts
index 8e07e145..bd6f7275 100644
--- a/test/unit/util.test.ts
+++ b/test/unit/util.test.ts
@@ -91,6 +91,17 @@ describe("parseRemoteAuthority", () => {
 			username: "foo",
 			workspace: "bar",
 		});
+		expect(
+			parseRemoteAuthority(
+				"vscode://ssh-remote+coder-vscode.dev.coder.xn--eckwd4c7cu47r2wf.jp--foo--bar",
+			),
+		).toStrictEqual({
+			agent: "",
+			sshHost: "coder-vscode.dev.coder.xn--eckwd4c7cu47r2wf.jp--foo--bar",
+			safeHostname: "dev.coder.xn--eckwd4c7cu47r2wf.jp",
+			username: "foo",
+			workspace: "bar",
+		});
 	});
 });