API: Fix case with abandoned partial paste

It is possible to abandon a paste while editing it on the web UI,
causing the database to have a state that the API was not expecting.
This filters out such pastes.

When we rewrite the paste.sr.ht frontend to work via GraphQL, we should
change the column to non-nullable and remove this where clause.

api/graph/schema.resolvers.go

@@ -302,7 +302,12 @@ func (r *queryResolver) Pastes(ctx context.Context, cursor *coremodel.Cursor) (*
 		query := database.
 			Select(ctx, paste).
 			From(`paste`).
-			Where(`paste.user_id = ?`, auth.ForContext(ctx).UserID)
+			Where(sq.And{
+				// TODO: Remove this and set the column to non-nullable after
+				// refactoring the frontend to create new pastes via GQL
+				sq.Expr(`paste.sha IS NOT NULL`),
+				sq.Expr(`paste.user_id = ?`, auth.ForContext(ctx).UserID),
+			})
 		pastes, cursor = paste.QueryWithCursor(ctx, tx, query, cursor)
 		return nil
 	}); err != nil {
@@ -331,6 +336,7 @@ func (r *userResolver) Pastes(ctx context.Context, obj *model.User, cursor *core
 			Select(ctx, paste).
 			From(`paste`).
 			Where(sq.And{
+				sq.Expr(`paste.sha IS NOT NULL`),
 				sq.Expr(`paste.user_id = ?`, obj.ID),
 				sq.Or{
 					sq.Expr(`paste.user_id = ?`, auth.ForContext(ctx).UserID),

pastesrht/default_query.graphql

@@ -7,11 +7,11 @@ query {
   me {
     # Grab their canonical name:
     canonicalName
-    # And a list of repositories:
+    # And a list of pastes:
     pastes {
       # This resource is paginated, so it has a cursor. If you pass this value
-      # into repositories(cursor:"...") in a subsequent request, you'll get the
-      # next page.
+      # into pastes(cursor:"...") in a subsequent request, you'll get the next
+      # page.
       cursor
       # These are the actual results. Grab the id, name, and updated fields
       # from each repository.