Undefined control sequence error when using tikz-uml package in LaTeX

Found the problem:

I have found the problem in the original tikz-uml.sty:

In its line 629 there is this statement:

\pgfmathsetmacro{\weightT}{1-\real{\weight}

The problem with it is the use of \real, that has been moved to other macro in the new version of pgfmathparser, and since the new version of PGF it is no longer available there to be used.

---

Got a solution:

The solution to this problem is as simple as:

1. Include the new TikZ library math.

2. Replace the line 629 with this code:

     \tikzmath{%
         real \weightT;%
         \weightT = 1 - real \weight;%               
     }%
   

---

Simple patch:

In order to patch the original version of tikz-uml.sty, we can apply the following patch to it:

--- tikz-uml.sty.orig   2015-10-10 23:44:04.978866966 -0300
+++ tikz-uml.sty    2015-10-10 23:29:46.902834319 -0300
@@ -16,7 +16,7 @@
 \RequirePackage{xstring}%
 \RequirePackage{calc}%
 \RequirePackage{pgfopts}%
-\usetikzlibrary{backgrounds,arrows,shapes,fit,shadows,decorations.markings}%
+\usetikzlibrary{backgrounds,arrows,shapes,fit,shadows,decorations.markings,math}%

 \def\tikzumlPackageLayersNum{3}%
 \pgfkeys{/tikzuml/options/.cd, packageLayers/.initial=3}%
@@ -626,7 +626,11 @@
   \setcounter{posT}{100*\real{\positionT}}%
   \setcounter{posStereo}{100*\real{\positionStereotype}}%
   %
-  \pgfmathsetmacro{\weightT}{1-\real{\weight}}%
+  % \pgfmathsetmacro{\weightT}{1-\real{\weight}}%
+  \tikzmath{%
+      real \weightT;%
+      \weightT = 1 - real \weight;%
+  }%
   %
   \def\tikzumlControlNodesNum{0}%
   %

If the patch above is saved in a file called tikz-uml.patch, in the same folder of the original library, then it can be applied this way:

cp tikz-uml.sty tikz-uml.sty.old
patch < tikz-uml.patch

I have had a similar issue since updating the pgf package to 3.0.1. Any connector usage in tikz-uml causes the pgfmath problem. I have written to Mr. Kielbasiewicz and await his reply as I am not savvy enough to unravel the mystery of this one. Meanwhile, reverting to an earlier pgf version has solved the problem for me.