When using dub, a project in the workspace root is required. Make it optional.

[Reavershark]

Because I'm using an external build system (esp-idf), my dub project is a subdirectory in the workspace.
Serve-d finds it just fine (with d.scanAllFolders) and uses it as a dub project, but gives an error when trying to set up the workspace folder as a project, which has no dub.sdl/json.

Currently there is no way to prevent the root folder being used as dub project (without d.neverUseDub).

One solution would be to not force add the workspace as a project, relying instead on d.scanAllFolders to find a dub.sdl/json in the workspace root. This would break projects using "d.scanAllFolders": false and not including "." in the d.extraRoots:

diff --git a/source/served/extension.d b/source/served/extension.d
index 715128e..a1a8d1d 100644
--- a/source/served/extension.d
+++ b/source/served/extension.d
@@ -506,31 +506,28 @@ RootSuggestion[] rootsForProject(string root, bool recursive, string[] blocked,
                if (!ret.canFind!(a => a.dir == dir))
                        ret ~= RootSuggestion(dir, useDub);
        }

-       bool rootDub = dubRecipeExists(root, true);
-       addSuggestion(root, rootDub);
-
        if (recursive)
        {
                foreach (pkg; tryDirEntries(root, "dub.{json,sdl}", fs.SpanMode.breadth))
                {
                        auto dir = dirName(pkg);
                        if (dir.canFind(".dub"))
                                continue;
-                       if (dir == root)
-                               continue;
                        if (blocked.any!(a => globMatch(dir.relativePath(root), a)
                                        || globMatch(pkg.relativePath(root), a) || globMatch((dir ~ "/").relativePath, a)))
                                continue;
                        addSuggestion(dir, true);
                }
        }

Alternatively, another config option could be added to always include the workspace root as dub project, defaulting to true.

[Reavershark]

It seems that a project in the workspace root is assumed to exist by onDidSaveDubRecipe and possibly in more places.