Fix dj.config issue on initial MATLAB boot.

Author: guzman-raphael

+dj/+internal/Settings.m

@@ -147,10 +147,14 @@ function envVarUpdate()
     % return STATE prior to change
     out = STATE;
     if any(strcmpi(operation, {'set', 'load'}))
-        % merge with existing STATE
-        STATE = rmfield(STATE, intersect(fieldnames(STATE), fieldnames(new)));
-        names = [fieldnames(STATE); fieldnames(new)];
-        STATE = orderfields(cell2struct([struct2cell(STATE); struct2cell(new)], names, 1));
+        if isempty(STATE)
+            STATE = new;
+        else
+            % merge with existing STATE
+            STATE = rmfield(STATE, intersect(fieldnames(STATE), fieldnames(new)));
+            names = [fieldnames(STATE); fieldnames(new)];
+            STATE = orderfields(cell2struct([struct2cell(STATE); struct2cell(new)], names, 1));
+        end
         if strcmpi(operation, 'load')
             envVarUpdate();
         end

docs-parts/intro/Releases_lang1.rst

@@ -2,6 +2,7 @@
 --------------------------
 * Bugfix: Error on accessing unmanaged Imported/Computed tables (#336) PR #338
 * Bugfix: Certain characters in attribute comment not escaped properly (#210, #335) PR #338
+* Bugfix: `dj.config.load(...)` after initial MATLAB boot throws invalid input error. PR #338
 
 3.4.0 -- December 11, 2020
 --------------------------

tests/TestConfig.m

@@ -197,6 +197,9 @@ function TestConfig_testLoad(testCase)
             base = regexprep(base,'[a-z0-9][A-Z]','${$0(1)}_${lower($0(2))}');
             TestConfig.TestConfig_configSingleFileTest(testCase, 'load-custom', ...
                 [pkg_path '/test_schemas/config_lite.json'], jsondecode(base));
+            % test load on launch MATLAB
+            clear functions;
+            dj.config.load([pkg_path '/test_schemas/config_lite.json']);
             % cleanup
             dj.config.restore;
         end