allow setting zig.path and zig.zls.path to null

`zig.path` and `zig.zls.path` default to an empty string which makes it
impossible to differentiate between an unset value and lookup in PATH.

The following issues will also be resolved:
- initial setup asks about Zig and ZLS even when using lookup in PATH
- initial setup returns early after installing Zig
- `checkInstalled` would error when ZLS is used from PATH

package.json

@@ -105,8 +105,11 @@
         },
         "zig.path": {
           "scope": "machine-overridable",
-          "type": "string",
-          "default": "",
+          "type": [
+            "string",
+            "null"
+          ],
+          "default": null,
           "description": "Set a custom path to the Zig binary. Empty string will lookup zig in PATH."
         },
         "zig.checkForUpdate": {
@@ -165,8 +168,11 @@
         },
         "zig.zls.path": {
           "scope": "machine-overridable",
-          "type": "string",
-          "default": "",
+          "type": [
+            "string",
+            "null"
+          ],
+          "default": null,
           "description": "Path to `zls` executable. Example: `C:/zls/zig-cache/bin/zls.exe`. Empty string will lookup ZLS in PATH.",
           "format": "path"
         },

src/zigSetup.ts

@@ -186,7 +186,7 @@ async function checkUpdate(context: vscode.ExtensionContext) {
 
 async function getUpdatedVersion(context: vscode.ExtensionContext): Promise<ZigVersion | null> {
     const configuration = vscode.workspace.getConfiguration("zig");
-    const zigPath = configuration.get<string>("path");
+    const zigPath = configuration.get<string | null>("path", null);
     if (zigPath) {
         const zigBinPath = vscode.Uri.joinPath(context.globalStorageUri, "zig_install", "zig").fsPath;
         if (!zigPath.startsWith(zigBinPath)) return null;
@@ -227,7 +227,8 @@ export async function setupZig(context: vscode.ExtensionContext) {
         await configuration.update("initialSetupDone", await initialSetup(context), true);
     }
 
-    if (!configuration.get<string>("path")) return;
+    // The `path` value may have changed after the initial setup is done but it will not need updating
+    if (!configuration.get<string | null>("path", null)) return; // also returns on ""
     if (!configuration.get<boolean>("checkForUpdate")) return;
     if (!(await shouldCheckUpdate(context, "zigUpdate"))) return;
     await checkUpdate(context);
@@ -236,7 +237,7 @@ export async function setupZig(context: vscode.ExtensionContext) {
 async function initialSetup(context: vscode.ExtensionContext): Promise<boolean> {
     const zigConfig = vscode.workspace.getConfiguration("zig");
 
-    if (zigConfig.get<string>("path") === "") {
+    if (zigConfig.get<string | null>("path", null) === null) {
         const zigResponse = await vscode.window.showInformationMessage(
             "Zig path hasn't been set, do you want to specify the path or install Zig?",
             { modal: true },
@@ -247,7 +248,7 @@ async function initialSetup(context: vscode.ExtensionContext): Promise<boolean>
         switch (zigResponse) {
             case "Install":
                 await selectVersionAndInstall(context);
-                const path = zigConfig.get<string>("path");
+                const path = vscode.workspace.getConfiguration("zig").get<string | null>("path", null);
                 if (!path) return false;
                 void vscode.window.showInformationMessage(
                     `Zig was installed at '${path}', add it to PATH to use it from the terminal`,
@@ -271,13 +272,14 @@ async function initialSetup(context: vscode.ExtensionContext): Promise<boolean>
                 await zigConfig.update("path", "", true);
                 break;
             case undefined:
+                await zigConfig.update("path", undefined, true);
                 return false;
         }
     }
 
     const zlsConfig = vscode.workspace.getConfiguration("zig.zls");
 
-    if (zlsConfig.get<string>("path") === "") {
+    if (zlsConfig.get<string | null>("path", null) === null) {
         const zlsResponse = await vscode.window.showInformationMessage(
             "We recommend enabling ZLS (the Zig Language Server) for a better editing experience. Would you like to install it?",
             { modal: true },
@@ -304,6 +306,8 @@ async function initialSetup(context: vscode.ExtensionContext): Promise<boolean>
                 await zlsConfig.update("path", "", true);
                 break;
             case undefined:
+                // explicitly set `zig.zls.path` to null so it is visible in the `settings.json`
+                await zlsConfig.update("path", null, true);
                 break;
         }
     }

src/zigUtil.ts

@@ -48,7 +48,7 @@ export function getExePath(exePath: string | null, exeName: string, optionName:
 
 export function getZigPath(): string {
     const configuration = vscode.workspace.getConfiguration("zig");
-    const zigPath = configuration.get<string>("path") ?? null;
+    const zigPath = configuration.get<string | null>("path", null);
     return getExePath(zigPath, "zig", "zig.path");
 }
 

src/zls.ts

@@ -93,7 +93,7 @@ export async function stopClient() {
 // returns the file system path to the zls executable
 export function getZLSPath(): string {
     const configuration = vscode.workspace.getConfiguration("zig.zls");
-    const zlsPath = configuration.get<string>("path") ?? null;
+    const zlsPath = configuration.get<string | null>("path", null);
     return getExePath(zlsPath, "zls", "zig.zls.path");
 }
 
@@ -127,7 +127,7 @@ async function getVersionIndex(): Promise<VersionIndex> {
 // checks whether there is newer version on master
 async function checkUpdate(context: vscode.ExtensionContext) {
     const configuration = vscode.workspace.getConfiguration("zig.zls");
-    const zlsPath = configuration.get<string>("path");
+    const zlsPath = configuration.get<string | null>("path", null);
     const zlsBinPath = vscode.Uri.joinPath(context.globalStorageUri, "zls_install", "zls").fsPath;
     if (!zlsPath) return;
     if (!zlsPath.startsWith(zlsBinPath)) return;
@@ -270,13 +270,14 @@ async function installVersion(context: vscode.ExtensionContext, version: semver.
 }
 
 function checkInstalled(): boolean {
-    const zlsPath = vscode.workspace.getConfiguration("zig.zls").get<string>("path");
-    if (!zlsPath) {
+    const zlsPath = vscode.workspace.getConfiguration("zig.zls").get<string | null>("path", null);
+    if (zlsPath === null) {
         void vscode.window.showErrorMessage("This command cannot be run without setting 'zig.zls.path'.", {
             modal: true,
         });
+        return false;
     }
-    return !!zlsPath;
+    return true;
 }
 
 export async function activate(context: vscode.ExtensionContext) {
@@ -323,14 +324,14 @@ export async function activate(context: vscode.ExtensionContext) {
         ) {
             await stopClient();
             const zlsConfig = vscode.workspace.getConfiguration("zig.zls");
-            if (!!zlsConfig.get<string>("path")) {
+            if (zlsConfig.get<string | null>("path", null) !== null) {
                 await startClient();
             }
         }
     }, context.subscriptions);
 
     const zlsConfig = vscode.workspace.getConfiguration("zig.zls");
-    if (zlsConfig.get<string>("path") === undefined) return;
+    if (zlsConfig.get<string | null>("path", null) === null) return;
     if (zlsConfig.get<boolean>("checkForUpdate") && (await shouldCheckUpdate(context, "zlsUpdate"))) {
         await checkUpdate(context);
     }