fix: read SSH settings from the active extension's section

CHANGELOG.md

@@ -25,6 +25,12 @@
 
 ### Fixed
 
+- Write the SSH config to the file the active Remote-SSH extension actually
+  reads. Windsurf/Devin and Antigravity renamed the whole `remote.SSH` settings
+  section, so a custom config file set as `remote.devinSSH.configFile`,
+  `remote.windsurfSSH.configFile`, or `remote.antigravitySSH.configFile` was
+  ignored and the workspace host was written to `~/.ssh/config` instead, where
+  those editors never looked for it.
 - Apply a 60-second default timeout to REST requests, so requests hung on a
   half-open TCP connection don't stall pollers forever.
 - Change `coder.binarySource`, `coder.binaryDestination`, `coder.headerCommand`,

src/remote/remote.ts

@@ -55,6 +55,7 @@ import {
 	parseCoderSshOptions,
 	parseSshConfig,
 } from "./sshConfig";
+import { getRemoteSshSetting } from "./sshExtension";
 import { applySettingOverrides, buildSshOverrides } from "./sshOverrides";
 import { SshProcessMonitor } from "./sshProcess";
 import { computeSshProperties, sshSupportsSetEnv } from "./sshSupport";
@@ -918,9 +919,7 @@ export class Remote {
 	}
 
 	private getSshConfigPath(): string {
-		const configured = vscode.workspace
-			.getConfiguration()
-			.get<string>("remote.SSH.configFile");
+		const configured = getRemoteSshSetting("configFile");
 		return expandPath(configured || path.join("~", ".ssh", "config"));
 	}
 

src/remote/sshExtension.ts

@@ -10,6 +10,34 @@ export const REMOTE_SSH_EXTENSION_IDS = [
 
 export type RemoteSshExtensionId = (typeof REMOTE_SSH_EXTENSION_IDS)[number];
 
+/**
+ * Sections each extension reads, in order. The rebranded forks renamed the
+ * whole `remote.SSH` section, so reading it directly misses them.
+ */
+const SETTING_SECTIONS: Readonly<
+	Record<RemoteSshExtensionId, readonly string[]>
+> = {
+	"jeanp413.open-remote-ssh": ["remote.SSH"],
+	// Windsurf became Devin and reads both, preferring the new name.
+	"codeium.windsurf-remote-openssh": ["remote.devinSSH", "remote.windsurfSSH"],
+	"anysphere.remote-ssh": ["remote.SSH"],
+	"ms-vscode-remote.remote-ssh": ["remote.SSH"],
+	"google.antigravity-remote-openssh": ["remote.antigravitySSH"],
+};
+
+/** First non-empty value for a string setting, e.g. `configFile`. */
+export function getRemoteSshSetting(key: string): string | undefined {
+	const id = getRemoteSshExtension()?.id;
+	const sections = id ? SETTING_SECTIONS[id] : ["remote.SSH"];
+	for (const section of sections) {
+		const value = vscode.workspace.getConfiguration(section).get<string>(key);
+		if (value) {
+			return value;
+		}
+	}
+	return undefined;
+}
+
 /**
  * VS Code Remote-SSH log layout, shared by the live SSH monitor and the
  * support-bundle collector so a future layout change updates one place.

test/unit/remote/sshExtension.test.ts

@@ -0,0 +1,59 @@
+import { describe, expect, it, vi } from "vitest";
+import * as vscode from "vscode";
+
+import { getRemoteSshSetting } from "@/remote/sshExtension";
+
+import { config, type Settings } from "../../mocks/testHelpers";
+
+/** Activate `extensionId`, or no Remote-SSH extension when empty. */
+function setup(extensionId: string, settings: Settings = {}): void {
+	config(settings);
+	vi.mocked(vscode.extensions.getExtension).mockImplementation((id) =>
+		id === extensionId ? ({ id } as vscode.Extension<unknown>) : undefined,
+	);
+}
+
+describe("getRemoteSshSetting", () => {
+	it.each([
+		["ms-vscode-remote.remote-ssh", "remote.SSH.configFile"],
+		["anysphere.remote-ssh", "remote.SSH.configFile"],
+		["jeanp413.open-remote-ssh", "remote.SSH.configFile"],
+		["google.antigravity-remote-openssh", "remote.antigravitySSH.configFile"],
+		["codeium.windsurf-remote-openssh", "remote.devinSSH.configFile"],
+	])("reads the section %s uses", (extensionId, settingKey) => {
+		setup(extensionId, { [settingKey]: "/custom/config" });
+
+		expect(getRemoteSshSetting("configFile")).toBe("/custom/config");
+	});
+
+	it("falls back to the legacy Windsurf section", () => {
+		setup("codeium.windsurf-remote-openssh", {
+			"remote.windsurfSSH.configFile": "/legacy/config",
+		});
+
+		expect(getRemoteSshSetting("configFile")).toBe("/legacy/config");
+	});
+
+	it("prefers the Devin section over the legacy Windsurf one", () => {
+		setup("codeium.windsurf-remote-openssh", {
+			"remote.devinSSH.configFile": "/devin/config",
+			"remote.windsurfSSH.configFile": "/legacy/config",
+		});
+
+		expect(getRemoteSshSetting("configFile")).toBe("/devin/config");
+	});
+
+	it("ignores another extension's section", () => {
+		setup("google.antigravity-remote-openssh", {
+			"remote.SSH.configFile": "/custom/config",
+		});
+
+		expect(getRemoteSshSetting("configFile")).toBeUndefined();
+	});
+
+	it("defaults to remote.SSH when no extension is installed", () => {
+		setup("", { "remote.SSH.configFile": "/custom/config" });
+
+		expect(getRemoteSshSetting("configFile")).toBe("/custom/config");
+	});
+});