Address 3820

When creating link destinations from a PDF's names dictionary as created by `.resolve_names()`, we incorrectly use strings with %-escaped spaces (and other characters) as keys to find dictionary values.
This change revert %-escaped names to the original. E.g. every "%20" sub-string is converted to a space, etc.

src/__init__.py

@@ -6835,6 +6835,17 @@ def uri_to_dict(uri):
                 else:
                     ret[item] = None
             return ret
+
+        def unescape(name):
+            """Unescape '%AB' substrings to chr(0xAB)."""
+            split = name.replace("%%", "%25")  # take care of escaped '%'
+            split = split.split("%")
+            newname = split[0]
+            for item in split[1:]:
+                piece = item[:2]
+                newname += chr(int(piece, base=16))
+                newname += item[2:]
+            return newname
 
         if rlink and not self.uri.startswith("#"):
             self.uri = f"#page={rlink[0] + 1}&zoom=0,{_format_g(rlink[1])},{_format_g(rlink[2])}"
@@ -6862,7 +6873,7 @@ def uri_to_dict(uri):
                         m = re.match('^#nameddest=(.*)', self.uri)
                         assert document
                         if document and m:
-                            named = m.group(1)
+                            named = unescape(m.group(1))
                             self.named = document.resolve_names().get(named)
                             if self.named is None:
                                 # document.resolve_names() does not contain an

tests/test_toc.py

@@ -16,6 +16,7 @@
 circular = os.path.join(scriptdir, "resources", "circular-toc.pdf")
 full_toc = os.path.join(scriptdir, "resources", "full_toc.txt")
 simple_toc = os.path.join(scriptdir, "resources", "simple_toc.txt")
+file_3820 = os.path.join(scriptdir, "resources", "test-3820.pdf")
 doc = pymupdf.open(filename)
 
 
@@ -274,3 +275,14 @@ def test_3400():
                 links_actual.append( (page_i, link) )
 
         assert links_actual == links_expected
+
+
+
+def test_3820():
+    """Ensure all extended TOC items point to pages."""
+    doc = pymupdf.open(file_3820)
+    toc = doc.get_toc(simple=False)
+    for _, _, epage, dest in toc:
+        assert epage == dest["page"] + 1
+
+