compile time validation of path (#2350)

* compile time validation of path

* added trybuild err message

* Update Cargo.toml

* add changelog entry

* test more cases of path validation

* fmt

Co-authored-by: Rob Ede <robjtede@icloud.com>

actix-web-codegen/tests/trybuild.rs

@@ -10,6 +10,7 @@ fn compile_macros() {
     t.compile_fail("tests/trybuild/route-missing-method-fail.rs");
     t.compile_fail("tests/trybuild/route-duplicate-method-fail.rs");
     t.compile_fail("tests/trybuild/route-unexpected-method-fail.rs");
+    t.compile_fail("tests/trybuild/route-malformed-path-fail.rs");
 
     t.pass("tests/trybuild/docstring-ok.rs");
 }

actix-web-codegen/tests/trybuild/route-malformed-path-fail.rs

@@ -0,0 +1,33 @@
+use actix_web_codegen::get;
+
+#[get("/{")]
+async fn zero() -> &'static str {
+    "malformed resource def"
+}
+
+#[get("/{foo")]
+async fn one() -> &'static str {
+    "malformed resource def"
+}
+
+#[get("/{}")]
+async fn two() -> &'static str {
+    "malformed resource def"
+}
+
+#[get("/*")]
+async fn three() -> &'static str {
+    "malformed resource def"
+}
+
+#[get("/{tail:\\d+}*")]
+async fn four() -> &'static str {
+    "malformed resource def"
+}
+
+#[get("/{a}/{b}/{c}/{d}/{e}/{f}/{g}/{h}/{i}/{j}/{k}/{l}/{m}/{n}/{o}/{p}/{q}")]
+async fn five() -> &'static str {
+    "malformed resource def"
+}
+
+fn main() {}

actix-web-codegen/tests/trybuild/route-malformed-path-fail.stderr

@@ -0,0 +1,42 @@
+error: custom attribute panicked
+ --> $DIR/route-malformed-path-fail.rs:3:1
+  |
+3 | #[get("/{")]
+  | ^^^^^^^^^^^^
+  |
+  = help: message: pattern "{" contains malformed dynamic segment
+
+error: custom attribute panicked
+ --> $DIR/route-malformed-path-fail.rs:8:1
+  |
+8 | #[get("/{foo")]
+  | ^^^^^^^^^^^^^^^
+  |
+  = help: message: pattern "{foo" contains malformed dynamic segment
+
+error: custom attribute panicked
+  --> $DIR/route-malformed-path-fail.rs:13:1
+   |
+13 | #[get("/{}")]
+   | ^^^^^^^^^^^^^
+   |
+   = help: message: Wrong path pattern: "/{}" regex parse error:
+               ((?s-m)^/(?P<>[^/]+))$
+                            ^
+           error: empty capture group name
+
+error: custom attribute panicked
+  --> $DIR/route-malformed-path-fail.rs:23:1
+   |
+23 | #[get("/{tail:\\d+}*")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: message: custom regex is not supported for tail match
+
+error: custom attribute panicked
+  --> $DIR/route-malformed-path-fail.rs:28:1
+   |
+28 | #[get("/{a}/{b}/{c}/{d}/{e}/{f}/{g}/{h}/{i}/{j}/{k}/{l}/{m}/{n}/{o}/{p}/{q}")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: message: Only 16 dynamic segments are allowed, provided: 17