Fix latex figure in admonition

Using figures in an admonition produces a LaTeX error ("Not in outer
par mode."). This is because it generates a float in a float. This can
be trivially fixed by overwriting the alignment to H, which is also
what is most probably intended.

CHANGES

@@ -18,6 +18,7 @@ Bugs fixed
 
 * #6286: C++, allow 8 and 9 in hexadecimal integer literals.
 * #6305: Fix the string in quickstart for 'path' argument of parser
+* LaTeX: Figures in admonitions produced errors
 
 Testing
 --------

sphinx/writers/latex.py

@@ -473,6 +473,7 @@ class LaTeXTranslator(SphinxTranslator):
         self.in_term = 0
         self.needs_linetrimming = 0
         self.in_minipage = 0
+        self.no_latex_floats = 0
         self.first_document = 1
         self.this_is_the_title = 1
         self.literal_whitespace = 0
@@ -1614,6 +1615,9 @@ class LaTeXTranslator(SphinxTranslator):
 
     def visit_figure(self, node):
         # type: (nodes.Element) -> None
+        align = self.elements['figure_align']
+        if self.no_latex_floats:
+            align = "H"
         if self.table:
             # TODO: support align option
             if 'width' in node:
@@ -1639,8 +1643,7 @@ class LaTeXTranslator(SphinxTranslator):
             self.body.append('\n\\begin{center}')
             self.context.append('\\end{center}\n')
         else:
-            self.body.append('\n\\begin{figure}[%s]\n\\centering\n' %
-                             self.elements['figure_align'])
+            self.body.append('\n\\begin{figure}[%s]\n\\centering\n' % align)
             if any(isinstance(child, nodes.caption) for child in node):
                 self.body.append('\\capstart\n')
             self.context.append('\\end{figure}\n')
@@ -1680,20 +1683,24 @@ class LaTeXTranslator(SphinxTranslator):
     def visit_admonition(self, node):
         # type: (nodes.Element) -> None
         self.body.append('\n\\begin{sphinxadmonition}{note}')
+        self.no_latex_floats += 1
 
     def depart_admonition(self, node):
         # type: (nodes.Element) -> None
         self.body.append('\\end{sphinxadmonition}\n')
+        self.no_latex_floats -= 1
 
     def _visit_named_admonition(self, node):
         # type: (nodes.Element) -> None
         label = admonitionlabels[node.tagname]
         self.body.append('\n\\begin{sphinxadmonition}{%s}{%s:}' %
                          (node.tagname, label))
+        self.no_latex_floats += 1
 
     def _depart_named_admonition(self, node):
         # type: (nodes.Element) -> None
         self.body.append('\\end{sphinxadmonition}\n')
+        self.no_latex_floats -= 1
 
     visit_attention = _visit_named_admonition
     depart_attention = _depart_named_admonition

tests/roots/test-latex-figure-in-admonition/conf.py

@@ -0,0 +1 @@
+exclude_patterns = ['_build']

tests/roots/test-latex-figure-in-admonition/index.rst

@@ -0,0 +1,9 @@
+Test Figure in Admonition
+=========================
+
+.. caution::
+
+   This uses a figure in an admonition.
+
+   .. figure:: img.png
+

tests/test_build_latex.py

@@ -1389,6 +1389,12 @@ def test_latex_labels(app, status, warning):
     assert result.count(r'\label{\detokenize{index:section1}}') == 1
 
 
+@pytest.mark.sphinx('latex', testroot='latex-figure-in-admonition')
+def test_latex_figure_in_admonition(app, status, warning):
+    app.builder.build_all()
+    result = (app.outdir / 'python.tex').text(encoding='utf8')
+    assert(r'\begin{figure}[H]' in result)
+
 def test_default_latex_documents():
     from sphinx.util import texescape
     texescape.init()