Fix infinite loop when reverse searching for next definition (#624)

Fixes #595 
Fixes #612

Author: OknoLombarda

CHANGELOG.md

@@ -7,6 +7,10 @@
 * [#622](https://github.com/clojure-emacs/clojure-mode/issues/622): Add font locking for missing clojure.core macros
 * [#615](https://github.com/clojure-emacs/clojure-mode/issues/615): Support clojure-dart files.
 
+### Bugs fixed
+
+* [#595](https://github.com/clojure-emacs/clojure-mode/issues/595), [#612](https://github.com/clojure-emacs/clojure-mode/issues/612): Fix buffer freezing when typing metadata for a definition
+
 ## 5.14.0 (2022-03-07)
 
 ### New features

clojure-mode.el

@@ -754,8 +754,11 @@ Called by `imenu--generic-function'."
               (when (char-equal ?\) (char-after (point)))
                 (backward-sexp)))
           (cl-destructuring-bind (def-beg . def-end) (bounds-of-thing-at-point 'sexp)
-            (if (char-equal ?^ (char-after def-beg))
-                (progn (forward-sexp) (backward-sexp))
+            (when (char-equal ?^ (char-after def-beg))
+              ;; move to the beginning of next sexp
+              (progn (forward-sexp) (backward-sexp)))
+            (when (or (not (char-equal ?^ (char-after (point))))
+                      (and (char-equal ?^ (char-after (point))) (= def-beg (point))))
               (setq found? t)
               (when (string= deftype "defmethod")
                 (setq def-end (progn (goto-char def-end)

test.clj

@@ -223,6 +223,10 @@
   ([x y & more]
      (reduce1 max (max x y) more)))
 
+
+;; definitions with metadata only don't cause freezing
+(def ^String)
+
 (defn ^String reverse
   "Returns s with its characters reversed."
   {:added "1.2"}

test/clojure-mode-syntax-test.el

@@ -60,6 +60,37 @@
       (expect (non-func "^hint " form) :to-be nil)
       (expect (non-func "#macro " form) :to-be nil))))
 
+(describe "clojure-match-next-def"
+  (let ((some-sexp "\n(list [1 2 3])"))
+    (it "handles vars with metadata"
+      (dolist (form '("(def ^Integer a 1)"
+                      "(def ^:a a 1)"
+                      "(def ^::a a 1)"
+                      "(def ^::a/b a 1)"
+                      "(def ^{:macro true} a 1)"))
+        (with-clojure-buffer (concat form some-sexp)
+          (end-of-buffer)
+          (clojure-match-next-def)
+          (expect (looking-at "(def")))))
+
+    (it "handles vars without metadata"
+      (with-clojure-buffer (concat "(def a 1)" some-sexp)
+        (end-of-buffer)
+        (clojure-match-next-def)
+        (expect (looking-at "(def"))))
+
+    (it "handles invalid def forms"
+      (dolist (form '("(def ^Integer)"
+                      "(def)"
+                      "(def ^{:macro})"
+                      "(def ^{:macro true})"
+                      "(def ^{:macro true} foo)"
+                      "(def ^{:macro} foo)"))
+        (with-clojure-buffer (concat form some-sexp)
+          (end-of-buffer)
+          (clojure-match-next-def)
+          (expect (looking-at "(def")))))))
+
 (describe "clojure syntax"
   (it "handles prefixed symbols"
     (dolist (form '(("#?@aaa" . "aaa")