Fix #2189: previous sibling link has broken if previous doc is under nested toctree

sphinx/environment.py

@@ -1950,63 +1950,31 @@ class BuildEnvironment:
                 for (key_, group) in groupby(newlist, keyfunc2)]
 
     def collect_relations(self):
+        traversed = set()
+
+        def traverse_toctree(parent, docname):
+            # traverse toctree by pre-order
+            yield parent, docname
+            traversed.add(docname)
+
+            for child in (self.toctree_includes.get(docname) or []):
+                for subparent, subdocname in traverse_toctree(docname, child):
+                    if subdocname not in traversed:
+                        yield subparent, subdocname
+                        traversed.add(subdocname)
+
         relations = {}
-        getinc = self.toctree_includes.get
+        docnames = traverse_toctree(None, self.config.master_doc)
+        prevdoc = None
+        parent, docname = docnames.next()
+        for nextparent, nextdoc in docnames:
+            relations[docname] = [parent, prevdoc, nextdoc]
+            prevdoc = docname
+            docname = nextdoc
+            parent = nextparent
 
-        def collect(parents, parents_set, docname, previous, next):
-            # circular relationship?
-            if docname in parents_set:
-                # we will warn about this in resolve_toctree()
-                return
-            if docname in relations:
-                return
-            includes = getinc(docname)
-            # previous
-            if not previous:
-                # if no previous sibling, go to parent
-                previous = parents[0][0]
-            else:
-                # else, go to previous sibling, or if it has children, to
-                # the last of its children, or if that has children, to the
-                # last of those, and so forth
-                while 1:
-                    previncs = getinc(previous)
-                    if previncs:
-                        previous = previncs[-1]
-                    else:
-                        break
-            # next
-            if includes:
-                # if it has children, go to first of them
-                next = includes[0]
-            elif next:
-                # else, if next sibling, go to it
-                pass
-            else:
-                # else, go to the next sibling of the parent, if present,
-                # else the grandparent's sibling, if present, and so forth
-                for parname, parindex in parents:
-                    parincs = getinc(parname)
-                    if parincs:
-                        for parinc in parincs[parindex + 1:]:
-                            if parinc in relations or parinc == docname:
-                                pass
-                            else:
-                                next = parinc
-                                break
+        relations[docname] = [parent, prevdoc, None]
 
-                        if next:
-                            break
-                # else it will stay None
-            # same for children
-            if includes:
-                for subindex, args in enumerate(zip(includes,
-                                                    [None] + includes,
-                                                    includes[1:] + [None])):
-                    collect([(docname, subindex)] + parents,
-                            parents_set.union([docname]), *args)
-            relations[docname] = [parents[0][0], previous, next]
-        collect([(None, 0)], set(), self.config.master_doc, None, None)
         return relations
 
     def check_consistency(self):

tests/roots/test-toctree-glob/bar/bar_4/index.rst

@@ -0,0 +1,4 @@
+Bar-4
+=====
+
+bar

tests/roots/test-toctree-glob/bar/index.rst

@@ -5,3 +5,4 @@ Bar
    :glob:
 
    *
+   bar_4/index

tests/roots/test-toctree-glob/index.rst

@@ -8,3 +8,4 @@ test-toctree-glob
    bar/index
    bar/*
    baz
+   qux/index

tests/roots/test-toctree-glob/quux.rst

@@ -0,0 +1,4 @@
+Quux
+====
+
+quux

tests/roots/test-toctree-glob/qux/index.rst

@@ -0,0 +1,8 @@
+Qux
+===
+
+.. toctree::
+   :glob:
+   :hidden:
+
+   *

tests/roots/test-toctree-glob/qux/qux_1.rst

@@ -0,0 +1,4 @@
+Qux-1
+=====
+
+qux

tests/roots/test-toctree-glob/qux/qux_2.rst

@@ -0,0 +1,4 @@
+Qux-1
+=====
+
+qux

tests/test_toctree.py

@@ -20,5 +20,10 @@ def test_relations(app, status, warning):
     assert app.builder.relations['bar/index'] == ['index', 'foo', 'bar/bar_1']
     assert app.builder.relations['bar/bar_1'] == ['bar/index', 'bar/index', 'bar/bar_2']
     assert app.builder.relations['bar/bar_2'] == ['bar/index', 'bar/bar_1', 'bar/bar_3']
-    assert app.builder.relations['bar/bar_3'] == ['bar/index', 'bar/bar_2', 'baz']
-    assert app.builder.relations['baz'] == ['index', 'bar/bar_3', None]
+    assert app.builder.relations['bar/bar_3'] == ['bar/index', 'bar/bar_2', 'bar/bar_4/index']
+    assert app.builder.relations['bar/bar_4/index'] == ['bar/index', 'bar/bar_3', 'baz']
+    assert app.builder.relations['baz'] == ['index', 'bar/bar_4/index', 'qux/index']
+    assert app.builder.relations['qux/index'] == ['index', 'baz', 'qux/qux_1']
+    assert app.builder.relations['qux/qux_1'] == ['qux/index', 'qux/index', 'qux/qux_2']
+    assert app.builder.relations['qux/qux_2'] == ['qux/index', 'qux/qux_1', None]
+    assert 'quux' not in app.builder.relations