Support docutils-0.18: Consume iterator of Element.traverse()

Since 0.18, Element.traverse() returns an iterator instead of
intermediate object.  As a result, the return value is always considered
as truthy value.  And it becomes fragile when the caller modifies the
doctree on the loop.

2 files changed, 3 insertions, 3 deletions

diff --git a/sphinx/writers/latex.py b/sphinx/writers/latex.py
index 869759ee5..3f032e616 100644
--- a/sphinx/writers/latex.py
+++ b/sphinx/writers/latex.py
@@ -651,7 +651,7 @@ class LaTeXTranslator(SphinxTranslator):
                 raise nodes.SkipNode
             else:
                 short = ''
-                if node.traverse(nodes.image):
+                if list(node.traverse(nodes.image)):
                     short = ('[%s]' % self.escape(' '.join(clean_astext(node).split())))
 
                 try:
diff --git a/sphinx/writers/manpage.py b/sphinx/writers/manpage.py
index 12fc31281..da5f4c241 100644
--- a/sphinx/writers/manpage.py
+++ b/sphinx/writers/manpage.py
@@ -56,7 +56,7 @@ class NestedInlineTransform:
 
     def apply(self, **kwargs: Any) -> None:
         matcher = NodeMatcher(nodes.literal, nodes.emphasis, nodes.strong)
-        for node in self.document.traverse(matcher):  # type: TextElement
+        for node in list(self.document.traverse(matcher)):  # type: TextElement
             if any(matcher(subnode) for subnode in node):
                 pos = node.parent.index(node)
                 for subnode in reversed(list(node)):
@@ -227,7 +227,7 @@ class ManualPageTranslator(SphinxTranslator, BaseTranslator):
 
     # overwritten -- don't make whole of term bold if it includes strong node
     def visit_term(self, node: Element) -> None:
-        if node.traverse(nodes.strong):
+        if list(node.traverse(nodes.strong)):
             self.body.append('\n')
         else:
             super().visit_term(node)