scoped \href arguments to avoid leaking color (#2433)

* scoped \href arguments to avoid leaking color

* add new test for color containment in \href

* reorganize+optimize around "bounded"; reuse test

lib/LaTeXML/Engine/Base_Utility.pool.ltxml

@@ -189,10 +189,7 @@ DefPrimitive('\@add@frontmatter OptionalKeyVals {} OptionalKeyVals {}', sub {
     $$entry[2] = Digest(Tokens(T_BEGIN, $tokens, T_END));
     AssignValue(inPreamble => $inpreamble);
     return; },
-  beforeDigest => sub {
-    $_[0]->bgroup; },
-  afterDigest => sub {
-    $_[0]->egroup; });
+  bounded => 1);
 
 # Append a piece of data to an existing frontmatter item that is contained in <$tag>
 # If $label is given, look for an item which has label=>$label,

lib/LaTeXML/Package/hyperref.sty.ltxml

@@ -186,6 +186,7 @@ DefMacro('\url', '\begingroup\lx@hyper@url\url', locked => 1);
 DefConstructor('\lx@hyper@url@ Undigested {}{} Semiverbatim {}',
   "?#isMath(<ltx:XMWrap class='#class' href='#href'>#5</ltx:XMWrap>)"    # Allow this to work in Math!
     . " (<ltx:ref href='#href' class='#class'>#5</ltx:ref>)",
+  bounded    => 1,
   properties => sub { (href => ComposeURL(LookupValue('BASE_URL'), $_[4]),
       class => sub { my $c = ToString($_[1]); $c =~ s/^\\//; 'ltx_' . $c; }); },
   sizer     => '#5',
@@ -205,6 +206,7 @@ DefMacro('\hyperref', '\@ifnextchar[\hyperref@@ii\hyperref@@iv');
 # 2 argument form
 DefConstructor('\hyperref@@ii OptionalSemiverbatim {}',
   "<ltx:ref labelref='#label'>#2</ltx:ref>",
+  bounded    => 1,
   properties => sub { (label => CleanLabel($_[1])); });
 # 4 argument form
 DefConstructor('\hyperref@@iv Semiverbatim Semiverbatim Semiverbatim Semiverbatim',

t/complex/hypertest.tex

@@ -3,6 +3,7 @@
 % Note also that older hyperxmp has fewer new options!
 \usepackage{hyperxmp}
 \usepackage[draft,pdftitle={Test Hyperref Metadata},backref]{hyperref}
+\usepackage{xcolor}
 \title{Test Hyperref Metadata}
 \author{A..~Author}
 \hypersetup{
@@ -39,4 +40,16 @@ \section{URL's}
 
 And, you get this: \url{http://example.com/\~{}user}
 
+\section{Bounded color}
+A link: \href{https://example.com}{\color{blue}here}.
+
+\subsection{Color should not leak into this heading}
+This text should be black.
+
+\def\simple#1#2{#1 and #2}
+A simple macro: \simple{\color{blue}first}{second}.
+
+\subsection{Color should leak into this heading}
+This text should be blue.
+
 \end{document}

t/complex/hypertest.xml

@@ -2,6 +2,7 @@
 <?latexml class="article"?>
 <?latexml package="hyperxmp"?>
 <?latexml package="hyperref" options="draft,pdftitle=Test Hyperref Metadata,backref"?>
+<?latexml package="xcolor"?>
 <?latexml RelaxNGSchema="LaTeXML"?>
 <document xmlns="http://dlmf.nist.gov/LaTeXML" class="ltx_authors_1line" prefix="cc: http://creativecommons.org/ns# dcterms: http://purl.org/dc/terms/">
   <resource src="LaTeXML.css" type="text/css"/>
@@ -46,6 +47,45 @@
       <p>And, you get this: <ref class="ltx_url" font="typewriter" href="http://example.com/~{}user">http://example.com/~{}user</ref></p>
     </para>
   </section>
+  <section inlist="toc" xml:id="S3">
+    <tags>
+      <tag>3</tag>
+      <tag role="autoref">section 3</tag>
+      <tag role="refnum">3</tag>
+      <tag role="typerefnum">§3</tag>
+    </tags>
+    <title><tag close=" ">3</tag>Bounded color</title>
+    <para xml:id="S3.p1">
+      <p>A link: <ref class="ltx_href" color="#0000FF" href="https://example.com">here</ref>.</p>
+    </para>
+    <subsection inlist="toc" xml:id="S3.SS1">
+      <tags>
+        <tag>3.1</tag>
+        <tag role="autoref">subsection 3.1</tag>
+        <tag role="refnum">3.1</tag>
+        <tag role="typerefnum">§3.1</tag>
+      </tags>
+      <title><tag close=" ">3.1</tag>Color should not leak into this heading</title>
+      <para xml:id="S3.SS1.p1">
+        <p>This text should be black.</p>
+      </para>
+      <para xml:id="S3.SS1.p2">
+        <p>A simple macro: <text color="#0000FF">first and second.</text></p>
+      </para>
+    </subsection>
+    <subsection inlist="toc" xml:id="S3.SS2">
+      <tags>
+        <tag>3.2</tag>
+        <tag role="autoref">subsection 3.2</tag>
+        <tag role="refnum">3.2</tag>
+        <tag role="typerefnum">§3.2</tag>
+      </tags>
+      <title color="#0000FF"><tag close=" ">3.2</tag>Color should leak into this heading</title>
+      <para xml:id="S3.SS2.p1">
+        <p><text color="#0000FF">This text should be blue.</text></p>
+      </para>
+    </subsection>
+  </section>
   <rdf about="" content="An Author" property="dcterms:creator"/>
   <rdf about="" content="Not subject to copyright" property="dcterms:rights"/>
   <rdf about="" content="test,hyperref" property="dcterms:subject"/>