Using @ in a nested .ecode does not work anymore (works in 3.0.1)

[fshaked]

The minimal example below, which works with pgf 3.0.1, now fails with this error:

./test.tex:13: Undefined control sequence.
<inserted text> \some
                      @val
l.13 \tikzset{a}

The example:

\documentclass{article}
\usepackage{tikz}

\makeatletter
\def\some@val{}
\tikzset{
  a/.style={
    b/.ecode={\some@val},
  }
}
\makeatother

\tikzset{a}

\begin{document}
empty
\end{document}

[hmenke]

Without having looked into this, it might be because of \scantokens in this bit

pgf/tex/generic/pgf/utilities/pgfkeys.code.tex

Lines 76 to 80 in 8aa15cc

	\long\def\pgfkeyssetevalue#1#2{%
	\pgfkeys@temptoks={#2}%
	\pgfkeys@temptoks=\scantokens\expandafter{\expandafter{\the\pgfkeys@temptoks}}%
	\expandafter\edef\csname pgfk@#1\expandafter\endcsname\expandafter{\the\pgfkeys@temptoks}%
	}

which is unfortunately needed if /.code takes arguments. Otherwise you run into the hash doubling problem.

[hmenke]

Workaround: Use \csname...\endcsname

\tikzset{
  a/.style={
    b/.ecode={\csname some@val\endcsname},
  }
}

[hmenke]

Related: #305

[hmenke]

@polgab You opened #305 long time ago and I merged your patch, but this led to the present issue. I'm tempted to revert back to the old behaviour.