From 65aa3502ccac62dca12b2c06957777107b457a6a Mon Sep 17 00:00:00 2001
From: Rob Ede <robjtede@icloud.com>
Date: Sat, 18 Dec 2021 03:49:32 +0000
Subject: [PATCH] soft deprecate `NormalizePath::default`

---
 CHANGES.md                  |  4 ++++
 actix-http/src/error.rs     |  2 +-
 src/middleware/normalize.rs | 14 +++++++++++++-
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/CHANGES.md b/CHANGES.md
index d9984224f..3a437fa1d 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,6 +1,10 @@
 # Changes
 
 ## Unreleased - 2020-xx-xx
+### Changed
+* Soft-deprecate `NormalizePath::default()`, noting upcoming behavior change in v4. [#2529]
+
+[#2529]: https://github.com/actix/actix-web/pull/2529
 
 
 ## 3.3.2 - 2020-12-01
diff --git a/actix-http/src/error.rs b/actix-http/src/error.rs
index e93c077af..70d2f8e8e 100644
--- a/actix-http/src/error.rs
+++ b/actix-http/src/error.rs
@@ -55,7 +55,7 @@ impl Error {
 
     /// Similar to `as_response_error` but downcasts.
     pub fn as_error<T: ResponseError + 'static>(&self) -> Option<&T> {
-        ResponseError::downcast_ref(self.cause.as_ref())
+        <dyn ResponseError>::downcast_ref(self.cause.as_ref())
     }
 }
 
diff --git a/src/middleware/normalize.rs b/src/middleware/normalize.rs
index ac8ad71d5..6bd3bcb7b 100644
--- a/src/middleware/normalize.rs
+++ b/src/middleware/normalize.rs
@@ -31,7 +31,7 @@ impl Default for TrailingSlash {
     }
 }
 
-#[derive(Default, Clone, Copy)]
+#[derive(Clone, Copy)]
 /// `Middleware` to normalize request's URI in place
 ///
 /// Performs following:
@@ -56,6 +56,18 @@ impl Default for TrailingSlash {
 
 pub struct NormalizePath(TrailingSlash);
 
+impl Default for NormalizePath {
+    fn default() -> Self {
+        log::warn!(
+            "`NormalizePath::default()` is deprecated. The default trailing slash behavior will \
+            change in v4 from `Always` to `Trim`. Update your call to `NormalizePath::new(...)` to \
+            avoid inaccessible routes when upgrading."
+        );
+
+        Self(TrailingSlash::default())
+    }
+}
+
 impl NormalizePath {
     /// Create new `NormalizePath` middleware with the specified trailing slash style.
     pub fn new(trailing_slash_style: TrailingSlash) -> Self {