From d2f44b801558d497cb4e001b744bb29abaa1fac0 Mon Sep 17 00:00:00 2001
From: Joel Kaasinen <joel.kaasinen@metosin.fi>
Date: Fri, 24 Oct 2025 09:58:03 +0300
Subject: [PATCH] fix: match-by-name! should throw when match-by-name is
 PartialMatch

If a path param was nil, match-by-name (via impl/path-for) was
treating the parameter as missing, but match-by-name!
(via impl/throw-on-missing-path-params) was treating it as present.

That is:

(reitit/match-by-name router :page {:id "1"}) ;; => Match
(reitit/match-by-name router :page) ;; => PartialMatch
(reitit/match-by-name router :page {:id nil}) ;; => PartialMatch

(reitit/match-by-name! router :page {:id "1"}) ;; => Match
(reitit/match-by-name! router :page) ;; => ExceptionInfo: missing path-params for route /pages/:id -> #{:id}
(reitit/match-by-name! router :page {:id nil}) ;; => nil  !!!

fixes #758
---
 modules/reitit-core/src/reitit/impl.cljc |  5 ++---
 test/cljc/reitit/core_test.cljc          | 12 +++++++++---
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/modules/reitit-core/src/reitit/impl.cljc b/modules/reitit-core/src/reitit/impl.cljc
index 164cbb82..b65e7b0e 100644
--- a/modules/reitit-core/src/reitit/impl.cljc
+++ b/modules/reitit-core/src/reitit/impl.cljc
@@ -198,9 +198,8 @@
     (:path route)))
 
 (defn throw-on-missing-path-params [template required path-params]
-  (when-not (every? #(contains? path-params %) required)
-    (let [defined (-> path-params keys set)
-          missing (set/difference required defined)]
+  (let [missing (set (remove #(get path-params %) required))]
+    (when-not (empty? missing)
       (ex/fail!
        (str "missing path-params for route " template " -> " missing)
        {:path-params path-params, :required required}))))
diff --git a/test/cljc/reitit/core_test.cljc b/test/cljc/reitit/core_test.cljc
index d60f2f41..17c3e4b2 100644
--- a/test/cljc/reitit/core_test.cljc
+++ b/test/cljc/reitit/core_test.cljc
@@ -13,8 +13,7 @@
 
   (testing "routers handling wildcard paths"
     (are [r name]
-      (testing "wild"
-
+      (testing (str name)
         (testing "simple"
           (let [router (r/router ["/api" ["/ipa" ["/:size" ::beer]]] {:router r})]
             (is (= name (r/router-name router)))
@@ -52,10 +51,17 @@
                        :path-params nil})
                      (r/match-by-name router ::beer)))
               (is (r/partial-match? (r/match-by-name router ::beer)))
+              (is (r/partial-match? (r/match-by-name router ::beer {:size nil}))
+                  "nil counts as missing")
               (is (thrown-with-msg?
                    ExceptionInfo
                    #"^missing path-params for route /api/ipa/:size -> \#\{:size\}$"
-                   (r/match-by-name! router ::beer))))))
+                   (r/match-by-name! router ::beer)))
+              (is (thrown-with-msg?
+                   ExceptionInfo
+                   #"^missing path-params for route /api/ipa/:size -> \#\{:size\}$"
+                   (r/match-by-name! router ::beer {:size nil}))
+                  "nil counts as missing"))))
 
         (testing "decode %-encoded path params"
           (let [router (r/router [["/one-param-path/:param1" ::one]