From f0cae8dbcf8d07035be069860fc4b22f7577d154 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lo=C3=AFc=20Hoguin?= <essen@ninenines.eu>
Date: Wed, 14 Nov 2018 16:42:46 +0100
Subject: Document some undefined behavior in cowboy_router

---
 doc/src/guide/routing.asciidoc | 8 ++++++++
 1 file changed, 8 insertions(+)

(limited to 'doc/src/guide/routing.asciidoc')

diff --git a/doc/src/guide/routing.asciidoc b/doc/src/guide/routing.asciidoc
index 47ef3c5..e5f8c33 100644
--- a/doc/src/guide/routing.asciidoc
+++ b/doc/src/guide/routing.asciidoc
@@ -124,6 +124,14 @@ You can also have imbricated optional segments.
 [source,erlang]
 PathMatch = "/hats/[page/[:number]]".
 
+While Cowboy does not reject multiple brackets in a route,
+the behavior may be undefined if the route is under-specified.
+For example, this route requires constraints to determine what
+is a chapter and what is a page, since they are both optional:
+
+[source,erlang]
+PathMatch = "/book/[:chapter]/[:page]".
+
 You can retrieve the rest of the host or path using `[...]`.
 In the case of hosts it will match anything before, in the case
 of paths anything after the previously matched segments. It is
-- 
cgit v1.2.3

