[#3] suggest seq over (not (empty? ...))

clj-kondo · Jul 7, 2019 · 9075043 · 9075043
1 parent 2e48e04
commit 9075043
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Showing 3 changed files with 26 additions and 2 deletions.
diff --git a/src/clj_kondo/impl/analyzer.clj b/src/clj_kondo/impl/analyzer.clj
@@ -811,6 +811,18 @@
   (analyze-children (ctx-with-linter-disabled ctx :unresolved-symbol)
                     (next (:children expr))))
 
+(defn analyze-empty?
+  [ctx expr]
+  (let [cs (:callstack ctx)
+        not-expr (one-of (second cs) [[clojure.core not] [cljs.core not]])]
+    (when not-expr
+      (findings/reg-finding!
+       (:findings ctx)
+       (node->line (:filename ctx) not-expr
+                   :warning :not-empty?
+                   "use the idiom (seq x) rather than (not (empty? x))")))
+    (analyze-children ctx (:children expr))))
+
 (defn analyze-call
   [{:keys [:top-level? :base-lang :lang :ns :config] :as ctx}
    {:keys [:arg-count
@@ -836,7 +848,8 @@
         ctx (if fq-sym
               (update ctx :callstack
                       (fn [cs]
-                        (cons [resolved-namespace resolved-name] cs)))
+                        (cons (with-meta [resolved-namespace resolved-name]
+                                (meta expr)) cs)))
               ctx)
         resolved-as-clojure-var-name
         (when (one-of resolved-as-namespace [clojure.core cljs.core])
@@ -897,6 +910,7 @@
           areduce (analyze-areduce ctx expr)
           this-as (analyze-this-as ctx expr)
           memfn (analyze-memfn ctx expr)
+          empty? (analyze-empty? ctx expr)
           ;; catch-all
           (case [resolved-namespace resolved-name]
             [schema.core defn]

diff --git a/src/clj_kondo/impl/config.clj b/src/clj_kondo/impl/config.clj
@@ -44,7 +44,8 @@
                                             (clojure.test/are)
                                             (clojure.test/is [thrown-with-msg?])
                                             ]}
-              :misplaced-docstring {:level :warning}}
+              :misplaced-docstring {:level :warning}
+              :not-empty? {:level :warning}}
     :lint-as {cats.core/->= clojure.core/->
               cats.core/->>= clojure.core/->>
               rewrite-clj.custom-zipper.core/defn-switchable clojure.core/defn

diff --git a/test/clj_kondo/main_test.clj b/test/clj_kondo/main_test.clj
@@ -1833,6 +1833,15 @@
                      :message "invalid function body"})
                   (lint! "(defn f \"dude\" x) (f 1)")))
 
+(deftest not-empty?-test
+  (assert-submaps
+   '({:file "<stdin>",
+      :row 1,
+      :col 1,
+      :level :warning,
+      :message "use the idiom (seq x) rather than (not (empty? x))"})
+   (lint! "(not (empty? [1]))")))
+
 ;;;; Scratch
 
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