2 files changed, 34 insertions, 1 deletions
diff --git a/Doc/tools/prechm.py b/Doc/tools/prechm.py
index 7b2f3936ce..57a43fd6fe 100644
--- a/Doc/tools/prechm.py
+++ b/Doc/tools/prechm.py
@@ -150,6 +150,22 @@ class Book:
 # Library Doc list of books:
 # each 'book' : (Dir, Title, First page, Content page, Index page)
 supported_libraries = {
+    '2.5':
+    [
+        Book('.', 'Main page', 'index'),
+        Book('.', 'Global Module Index', 'modindex'),
+        Book('whatsnew', "What's New", 'index', 'contents'),
+        Book('tut','Tutorial','tut','node2'),
+        Book('lib','Library Reference','lib','contents','genindex'),
+        Book('ref','Language Reference','ref','contents','genindex'),
+        Book('mac','Macintosh Reference','mac','contents','genindex'),
+        Book('ext','Extending and Embedding','ext','contents'),
+        Book('api','Python/C API','api','contents','genindex'),
+        Book('doc','Documenting Python','doc','contents'),
+        Book('inst','Installing Python Modules', 'inst', 'index'),
+        Book('dist','Distributing Python Modules', 'dist', 'index', 'genindex'),
+    ],
+
     '2.4':
     [
         Book('.', 'Main page', 'index'),
diff --git a/Doc/tools/toc2bkm.py b/Doc/tools/toc2bkm.py
index 636459a315..ab669ba959 100755
--- a/Doc/tools/toc2bkm.py
+++ b/Doc/tools/toc2bkm.py
@@ -44,6 +44,20 @@ _transition_map = {
 INCLUDED_LEVELS = ("chapter", "section", "subsection", "subsubsection")
 
 
+class BadSectionNesting(Exception):
+    """Raised for unsupported section level transitions."""
+
+    def __init__(self, level, newsection, path, lineno):
+        self.level = level
+        self.newsection = newsection
+        self.path = path
+        self.lineno = lineno
+
+    def __str__(self):
+        return ("illegal transition from %s to %s at %s (line %s)"
+                % (self.level, self.newsection, self.path, self.lineno))
+
+
 def parse_toc(fp, bigpart=None):
     toc = top = []
     stack = [toc]
@@ -65,7 +79,10 @@ def parse_toc(fp, bigpart=None):
                 if stype not in INCLUDED_LEVELS:
                     # we don't want paragraphs & subparagraphs
                     continue
-                direction = _transition_map[(level, stype)]
+                try:
+                    direction = _transition_map[(level, stype)]
+                except KeyError:
+                    raise BadSectionNesting(level, stype, fp.name, lineno)
                 if direction == OUTER_TO_INNER:
                     toc = toc[-1][-1]
                     stack.insert(0, toc)