Fix for no internet and no local versions installed

src/zim.zig

@@ -156,9 +156,13 @@ fn getRemoteVersionsSlice(allocator: std.mem.Allocator) ZimError![]const ZigVers
         var client = std.http.Client{ .allocator = allocator };
         defer client.deinit();
 
-        var request = client.request(.GET, versions_json_uri, headers, .{}) catch {
+        var request = client.request(.GET, versions_json_uri, headers, .{}) catch |err| {
-            std.debug.print("Error creating request\n", .{});
+            if (err == error.TemporaryNameServerFailureError) {
+                std.debug.print("Name Server for {s} could not be resolved. Check your internet connection.", .{versions_json_url});
                 return ZimError.NetworkError;
+            }
+            std.debug.print("Error creating request\n{any}\n", .{err});
+            return ZimError.Unexpected;
         };
         defer request.deinit();
 
@@ -239,7 +243,7 @@ fn shellName(s: ?ShellType) string {
 }
 
 fn printZimPathHelp(shell_tag: ?ShellType, zim_path: string) void {
-    if (shell_tag == undefined) {
+    if (shell_tag == null) {
         std.debug.print("Unrecognized shell\n", .{});
         return;
     }
@@ -311,7 +315,7 @@ fn downloadAndExtractTarball(allocator: std.mem.Allocator, zv: ZigVersion) ZimEr
     const tar_buf_len = 38;
     var tar_arr: [tar_buf_len]u8 = undefined;
     var tar_buf = tar_arr[0..];
-    const tarball_file_name = std.fmt.bufPrint(tar_buf, "zig-{s}.tar", .{ zim_path, zv.version_string }) catch {
+    const tarball_file_name = std.fmt.bufPrint(tar_buf, "zig-{s}.tar", .{zv.version_string}) catch {
         return ZimError.Memory;
     };
 
@@ -319,7 +323,7 @@ fn downloadAndExtractTarball(allocator: std.mem.Allocator, zv: ZigVersion) ZimEr
     const full_tar_buf_len = buf_len + tar_buf_len + 10;
     var full_tar_arr: [full_tar_buf_len]u8 = undefined;
     var full_tar_buf = full_tar_arr[0..];
-    const full_path_tarball_file_name = std.fmt.bufPrint(full_tar_buf, "{s}/versions/{s}", .{ zim_path, tarball_file_name}) catch {
+    const full_path_tarball_file_name = std.fmt.bufPrint(full_tar_buf, "{s}/versions/{s}", .{ zim_path, tarball_file_name }) catch {
         return ZimError.Memory;
     };
 
@@ -348,7 +352,7 @@ fn downloadAndExtractTarball(allocator: std.mem.Allocator, zv: ZigVersion) ZimEr
 
     // Remove tarball file
     zim_dir.deleteFile(full_path_tarball_file_name) catch |err| {
-    	std.debug.print("Could not remove {s}: {any}\n", .{tarball_file_name, err});
+        std.debug.print("Could not remove {s}: {any}\n", .{ tarball_file_name, err });
         return ZimError.BadIO;
     };
 
@@ -472,6 +476,9 @@ pub fn list(allocator: std.mem.Allocator, param: string) !void {
                 std.debug.print("\n  [{d}]\tZig Version {s}", .{ i + 1, version_str });
                 i += 1;
             }
+            if (i == 0) {
+                std.debug.print("\nNo local versions installed\nTry `zim install help`\n", .{});
+            } else {
                 std.debug.print("\n", .{});
                 std.debug.print(
                     \\
@@ -479,6 +486,7 @@ pub fn list(allocator: std.mem.Allocator, param: string) !void {
                     \\  You can also just specify the index of the version you would like to use.
                     \\
                 , .{});
+            }
 
             return;
         },