From 711b8ecf70b613c8decabc9ab0d1895169f4b89c Mon Sep 17 00:00:00 2001
From: jfbu <jfbu@free.fr>
Date: Sun, 11 Mar 2018 11:36:16 +0100
Subject: [PATCH 1/2] Fix vertical space before equation in latex (closes:
 #4574)

---
 sphinx/writers/latex.py                       |  4 ++++
 tests/roots/test-latex-equations/conf.py      |  5 +++++
 .../roots/test-latex-equations/equations.rst  | 21 +++++++++++++++++++
 .../expects/latex-equations.tex               | 13 ++++++++++++
 tests/test_build_latex.py                     | 10 +++++++++
 5 files changed, 53 insertions(+)
 create mode 100644 tests/roots/test-latex-equations/conf.py
 create mode 100644 tests/roots/test-latex-equations/equations.rst
 create mode 100644 tests/roots/test-latex-equations/expects/latex-equations.tex

diff --git a/sphinx/writers/latex.py b/sphinx/writers/latex.py
index ca410c4e9..bdb2a92b3 100644
--- a/sphinx/writers/latex.py
+++ b/sphinx/writers/latex.py
@@ -1959,6 +1959,10 @@ class LaTeXTranslator(nodes.NodeVisitor):
             if id.startswith('index-'):
                 return
 
+            # equations also need no extra blank line nor hypertarget
+            if id.startswith('equation-'):
+                return
+
             # insert blank line, if the target follows a paragraph node
             index = node.parent.index(node)
             if index > 0 and isinstance(node.parent[index - 1], nodes.paragraph):
diff --git a/tests/roots/test-latex-equations/conf.py b/tests/roots/test-latex-equations/conf.py
new file mode 100644
index 000000000..6122e9212
--- /dev/null
+++ b/tests/roots/test-latex-equations/conf.py
@@ -0,0 +1,5 @@
+# -*- coding: utf-8 -*-
+
+master_doc = 'equations'
+extensions = ['sphinx.ext.imgmath']
+
diff --git a/tests/roots/test-latex-equations/equations.rst b/tests/roots/test-latex-equations/equations.rst
new file mode 100644
index 000000000..2eef2f2a4
--- /dev/null
+++ b/tests/roots/test-latex-equations/equations.rst
@@ -0,0 +1,21 @@
+test-latex-equation
+===================
+
+Equation without a label.
+
+.. math::
+
+   E = mc^2
+
+Equation with label.
+
+.. math:: E = hv
+   :label: test
+
+Second equation without label.
+
+.. math::
+
+   c^2 = a^2 + b^2
+
+Equation with label :eq:`test` is important.
diff --git a/tests/roots/test-latex-equations/expects/latex-equations.tex b/tests/roots/test-latex-equations/expects/latex-equations.tex
new file mode 100644
index 000000000..ce07a0128
--- /dev/null
+++ b/tests/roots/test-latex-equations/expects/latex-equations.tex
@@ -0,0 +1,13 @@
+Equation without a label.
+\begin{equation*}
+\begin{split}E = mc^2\end{split}
+\end{equation*}
+Equation with label.
+\begin{equation}\label{equation:equations:test}
+\begin{split}E = hv\end{split}
+\end{equation}
+Second equation without label.
+\begin{equation*}
+\begin{split}c^2 = a^2 + b^2\end{split}
+\end{equation*}
+Equation with label \eqref{equation:equations:test} is important.
diff --git a/tests/test_build_latex.py b/tests/test_build_latex.py
index 4b02b7c54..602429a96 100644
--- a/tests/test_build_latex.py
+++ b/tests/test_build_latex.py
@@ -1134,6 +1134,16 @@ def test_latex_index(app, status, warning):
     assert '\n\\index{Einstein}\\index{relativity}\\ignorespaces \nand' in result
 
 
+@pytest.mark.sphinx('latex', testroot='latex-equations')
+def test_latex_equations(app, status, warning):
+    app.builder.build_all()
+
+    result = (app.outdir / 'Python.tex').text(encoding='utf8')
+    expected = (app.srcdir / 'expects' / 'latex-equations.tex').text().strip()
+
+    assert expected in result
+
+
 @pytest.mark.sphinx('latex', testroot='image-in-parsed-literal')
 def test_latex_image_in_parsed_literal(app, status, warning):
     app.builder.build_all()

From c4e12ff01231d468682264b5d856aa78c39eeb19 Mon Sep 17 00:00:00 2001
From: jfbu <jfbu@free.fr>
Date: Mon, 12 Mar 2018 17:00:01 +0100
Subject: [PATCH 2/2] Add TODO notes

	modified:   sphinx/ext/mathbase.py
	modified:   sphinx/writers/latex.py
---
 sphinx/ext/mathbase.py  | 1 +
 sphinx/writers/latex.py | 1 +
 2 files changed, 2 insertions(+)

diff --git a/sphinx/ext/mathbase.py b/sphinx/ext/mathbase.py
index 15218963f..513ddd62a 100644
--- a/sphinx/ext/mathbase.py
+++ b/sphinx/ext/mathbase.py
@@ -86,6 +86,7 @@ class MathDomain(Domain):
                 newnode['target'] = target
                 return newnode
             else:
+                # TODO: perhaps use rather a sphinx-core provided prefix here?
                 node_id = make_id('equation-%s' % target)
                 if env.config.math_numfig and env.config.numfig:
                     if docname in env.toc_fignumbers:
diff --git a/sphinx/writers/latex.py b/sphinx/writers/latex.py
index bdb2a92b3..1558a29d7 100644
--- a/sphinx/writers/latex.py
+++ b/sphinx/writers/latex.py
@@ -1960,6 +1960,7 @@ class LaTeXTranslator(nodes.NodeVisitor):
                 return
 
             # equations also need no extra blank line nor hypertarget
+            # TODO: fix this dependency on mathbase extension internals
             if id.startswith('equation-'):
                 return