Fix #380: Preserve line breaks after #_ uneval tags to prevent moving…

README.md

@@ -301,6 +301,13 @@ In order to load the standard configuration file from Leiningen, add the
 
   Defaults to `:community`
 
+* `:ignore-lines-with-only-uneval-tags?` -
+  true if cljfmt should preserve linebreaks after `#_` uneval tags that
+  appear on their own line. When true (default), `#_` followed by a newline
+  will not be moved to the same line as the following form. When false,
+  `#_` tags will be formatted onto the same line as the form they comment
+  out. Defaults to true.
+
 * `:indent-line-comments?` -
   true if cljfmt should align whole-line `;;` comments with the code.
   Defaults to false.

cljfmt/src/cljfmt/core.cljc

@@ -61,19 +61,23 @@
 (defn- comment? [zloc]
   (some-> zloc z/node n/comment?))
 
-(defn- surrounding-whitespace? [zloc]
+(defn- uneval? [zloc]
+  (= (z/tag zloc) :uneval))
+
+(defn- surrounding-whitespace? [zloc opts]
   (and (not (top? zloc))
        (clojure-whitespace? zloc)
+       (not (and (:ignore-lines-with-only-uneval-tags? opts)
+                 (z/linebreak? zloc)
+                 (nil? (z/left* zloc))
+                 (uneval? (z/up* zloc))))
        (or (and (nil? (z/left* zloc))
                 ;; don't convert ~ @ to ~@
                 (not (unquote-deref? (z/right* zloc)))
                 ;; ignore space before comments
                 (not (comment? (z/right* zloc))))
            (nil? (z/skip z/right* clojure-whitespace? zloc)))))
 
-(defn remove-surrounding-whitespace [form]
-  (transform form edit-all surrounding-whitespace? z/remove*))
-
 (defn- element? [zloc]
   (and zloc (not (z/whitespace-or-comment? zloc))))
 
@@ -209,9 +213,6 @@
 (defn- coll-indent [zloc]
   (-> zloc z/leftmost* margin))
 
-(defn- uneval? [zloc]
-  (= (z/tag zloc) :uneval))
-
 (defn- index-of [zloc]
   (->> (iterate z/left zloc)
        (remove uneval?)
@@ -236,11 +237,24 @@
     :cursive (cursive-two-space-list-indent? zloc)
     :zprint (zprint-two-space-list-indent? zloc)))
 
+(defn- first-form-in-line? [zloc]
+  (if-let [zloc (z/left* zloc)]
+    (if (space? zloc)
+      (recur zloc)
+      (or (z/linebreak? zloc) (comment? zloc)))
+    true))
+
 (defn- list-indent [zloc context]
-  (if (> (index-of zloc) 1)
-    (-> zloc z/leftmost* z/right margin)
-    (cond-> (coll-indent zloc)
-      (two-space-list-indent? zloc context) inc)))
+  (let [idx (index-of zloc)
+        has-uneval-before? #(and (= idx 1) (-> zloc z/left* uneval?))]
+    (if (or (> idx 1) (has-uneval-before?))
+      (let [first-arg (-> zloc z/leftmost* z/right)]
+        (cond-> (margin first-arg)
+          (not (or (not (uneval? first-arg)) (first-form-in-line? first-arg)))
+          inc))
+      (cond-> (coll-indent zloc)
+        (two-space-list-indent? zloc context)
+        inc))))
 
 (def indent-size 2)
 
@@ -340,14 +354,6 @@
           (z/leftmost zloc)
           (repeat n z/right)))
 
-(defn- first-form-in-line? [zloc]
-  (and (some? zloc)
-       (if-let [zloc (z/left* zloc)]
-         (if (space? zloc)
-           (recur zloc)
-           (or (z/linebreak? zloc) (comment? zloc)))
-         true)))
-
 (defn- block-indent [zloc key idx context]
   (when (form-matches-key? zloc key context)
     (let [zloc-after-idx (some-> zloc (nth-form (inc idx)))]
@@ -378,6 +384,7 @@
    :extra-blank-line-forms                {}
    :extra-indents                         {}
    :function-arguments-indentation        :community
+   :ignore-lines-with-only-uneval-tags?   true
    :indent-line-comments?                 false
    :indentation?                          true
    :indents                               default-indents
@@ -405,6 +412,12 @@
     (when (form-matches-key? zloc sym context)
       (list-indent zloc context))))
 
+(defn remove-surrounding-whitespace
+  ([form]
+   (remove-surrounding-whitespace form default-options))
+  ([form opts]
+   (transform form edit-all #(surrounding-whitespace? % opts) z/remove*)))
+
 (defn- make-indenter [[key opts] context]
   (apply some-fn (map (partial indenter-fn key context) opts)))
 
@@ -433,6 +446,8 @@
       (reader-conditional? gp) (coll-indent zloc)
       (#{:list :fn} tag)       (custom-indent zloc indents context)
       (= :meta tag)            (indent-amount (z/up zloc) indents context)
+      (= :uneval tag)          (cond-> (margin (z/up zloc))
+                                 (not (first-form-in-line? (z/up zloc))) inc)
       :else                    (coll-indent zloc))))
 
 (defn- indent-line [zloc indents context]
@@ -827,7 +842,7 @@
          (cond-> (:remove-consecutive-blank-lines? opts)
            remove-consecutive-blank-lines)
          (cond-> (:remove-surrounding-whitespace? opts)
-           remove-surrounding-whitespace)
+           (remove-surrounding-whitespace opts))
          (cond-> (:insert-missing-whitespace? opts)
            insert-missing-whitespace)
          (cond-> (:remove-multiple-non-indenting-spaces? opts)

cljfmt/src/cljfmt/main.clj

@@ -38,6 +38,9 @@
     :validate [#{:community :cursive :zprint}
                "Must be one of community, cursive, or zprint"]
     :id :function-arguments-indentation]
+   [nil "--[no-]ignore-lines-with-only-uneval-tags"
+    :default (:ignore-lines-with-only-uneval-tags? defaults)
+    :id :ignore-lines-with-only-uneval-tags?]
    [nil "--[no-]indentation"
     :default (:indentation? defaults)
     :id :indentation?]

cljfmt/test/cljfmt/core_test.cljc

@@ -1039,7 +1039,160 @@
          ["#?(:cljs (bar 1) :clj (foo 2))"]))
     (is (reformats-to?
          ["#?@(:cljs[foo bar] :clj[baz quux])"]
-         ["#?@(:cljs [foo bar] :clj [baz quux])"]))))
+         ["#?@(:cljs [foo bar] :clj [baz quux])"])))
+
+  (testing "uneval on own line"
+    (is (reformats-to?
+         ["#_"
+          "(defn foobar []"
+          "  (do-this)"
+          "  (let [x 1]"
+          "    (with-blah []"
+          "      (stuff))))"]
+         ["#_"
+          "(defn foobar []"
+          "  (do-this)"
+          "  (let [x 1]"
+          "    (with-blah []"
+          "      (stuff))))"]
+         {:ignore-lines-with-only-uneval-tags? true}))
+    (is (reformats-to?
+         ["#_"
+          "{:foo :bar}"]
+         ["#_"
+          "{:foo :bar}"]
+         {:ignore-lines-with-only-uneval-tags? true}))
+    (is (reformats-to?
+         ["(foo #_"
+          "     bar"
+          "     baz)"]
+         ["(foo #_"
+          "      bar"
+          "      baz)"]
+         {:ignore-lines-with-only-uneval-tags? true}))
+    (testing "uneval on same line still gets whitespace"
+      (is (reformats-to?
+           ["(foo #_bar baz)"]
+           ["(foo #_bar baz)"]
+           {:ignore-lines-with-only-uneval-tags? true})))
+    (testing "multiple unevals on own lines"
+      (is (reformats-to?
+           ["#_"
+            "(defn foo [])"
+            "#_"
+            "(defn bar [])"]
+           ["#_"
+            "(defn foo [])"
+            "#_"
+            "(defn bar [])"]
+           {:ignore-lines-with-only-uneval-tags? true})))
+    (testing "uneval with vector"
+      (is (reformats-to?
+           ["#_"
+            "[1 2 3]"]
+           ["#_"
+            "[1 2 3]"]
+           {:ignore-lines-with-only-uneval-tags? true})))
+    (testing "uneval with map"
+      (is (reformats-to?
+           ["#_"
+            "{:a 1"
+            " :b 2}"]
+           ["#_"
+            "{:a 1"
+            " :b 2}"]
+           {:ignore-lines-with-only-uneval-tags? true})))
+    (testing "uneval as function argument"
+      (is (reformats-to?
+           ["(foo"
+            " #_"
+            " bar"
+            " baz)"]
+           ["(foo"
+            " #_"
+            " bar"
+            " baz)"]
+           {:ignore-lines-with-only-uneval-tags? true}))
+      (testing "with more than one argument"
+        (is (reformats-to?
+             ["(foo"
+              " #_"
+              " x"
+              " y"
+              " z)"]
+             ["(foo"
+              " #_"
+              " x"
+              " y"
+              " z)"]
+             {:ignore-lines-with-only-uneval-tags? true}))))
+    (testing "uneval before closing paren"
+      (is (reformats-to?
+           ["(foo bar"
+            " #_"
+            " baz)"]
+           ["(foo bar"
+            "     #_"
+            "     baz)"]
+           {:ignore-lines-with-only-uneval-tags? true})))
+    (testing "multiple unevals inline"
+      (is (reformats-to?
+           ["(foo #_ bar #_ baz qux)"]
+           ["(foo #_bar #_baz qux)"]
+           {:ignore-lines-with-only-uneval-tags? true})))
+    (testing "uneval with reader conditional"
+      (is (reformats-to?
+           ["#_"
+            "#?(:clj (foo)"
+            "   :cljs (bar))"]
+           ["#_"
+            "#?(:clj (foo)"
+            "   :cljs (bar))"]
+           {:ignore-lines-with-only-uneval-tags? true})))
+    (testing "uneval with cursive indentation"
+      (is (reformats-to?
+           ["(foo"
+            " #_"
+            " bar"
+            " baz)"]
+           ["(foo"
+            "  #_"
+            "  bar"
+            "  baz)"]
+           {:function-arguments-indentation :cursive
+            :ignore-lines-with-only-uneval-tags? true})))
+    (testing "uneval inline with cursive indentation"
+      (is (reformats-to?
+           ["(foo #_"
+            "     bar"
+            "     baz)"]
+           ["(foo #_"
+            "      bar"
+            "      baz)"]
+           {:function-arguments-indentation :cursive
+            :ignore-lines-with-only-uneval-tags? true})))
+    (testing "uneval with zprint indentation"
+      (is (reformats-to?
+           ["(foo"
+            " #_"
+            " bar"
+            " baz)"]
+           ["(foo"
+            "  #_"
+            "  bar"
+            "  baz)"]
+           {:function-arguments-indentation :zprint
+            :ignore-lines-with-only-uneval-tags? true})))
+    (testing "uneval inline with zprint indentation"
+      (is (reformats-to?
+           ["(foo #_"
+            "     bar"
+            "     baz)"]
+           ["(foo #_"
+            "      bar"
+            "      baz)"]
+           {:function-arguments-indentation :zprint
+            :ignore-lines-with-only-uneval-tags? true})))))
 
 (deftest test-consecutive-blank-lines
   (is (reformats-to?