Fix mostly some compiler warnings

Author: nagy

Makefile

@@ -1,11 +1,13 @@
 .PHONY: test clean install run
 
-ELS  =  nix.el nix-company.el nix-drv-mode.el nix-format.el \
+ELS  =  nix.el nix-company.el nix-drv-mode.el nix-flake.el nix-format.el \
 	nix-instantiate.el nix-mode.el nix-mode-mmm.el \
 	nix-prettify-mode.el nix-repl.el nix-search.el nix-shebang.el \
 	nix-shell.el nix-store.el
 ELCS = $(ELS:.el=.elc)
 
+DOCS = nix-mode.pdf nix-mode.html nix-mode.info
+
 TESTS = tests/nix-mode-tests.el tests/nix-font-lock-tests.el
 
 DESTDIR =

nix-edit.el

@@ -27,7 +27,7 @@ ATTR the attribute to find in nix expressions."
     (call-process nix-executable nil (list stdout nil) nil
 		  "edit" "-f" file attr)
     (with-current-buffer stdout
-      (when (eq (buffer-size) 0)
+      (when (zerop (buffer-size))
 	(error
 	 "Error: nix edit failed to produce any output"))
       (setq result (substring (buffer-string) 0 (- (buffer-size) 1))))

nix-format.el

@@ -13,14 +13,13 @@
   :group 'nix
   :type 'string)
 
-(if (fboundp 'replace-buffer-contents)
-    (defun nix--replace-buffer-contents (src dst)
-      (with-current-buffer dst (replace-buffer-contents src)))
-  (defun nix--replace-buffer-contents (src dst)
-    (if (not (string= (with-current-buffer src (buffer-string))
-		      (with-current-buffer dst (buffer-string))))
-	(with-current-buffer src
-	  (copy-to-buffer dst (point-min) (point-max))))))
+(defun nix--replace-buffer-contents (src dst)
+  (if (fboundp 'replace-buffer-contents)
+      (with-current-buffer dst (replace-buffer-contents src))
+    (unless  (string= (with-current-buffer src (buffer-string))
+		      (with-current-buffer dst (buffer-string)))
+      (with-current-buffer src
+	(copy-to-buffer dst (point-min) (point-max))))))
 
 (defun nix--format-call (buf nixfmt-bin)
   "Format BUF using nixfmt."

nix-search.el

@@ -20,7 +20,7 @@
   (nix--process-json-nocheck "search" "--json"
 			     (unless use-flakes "--file") file
 			     (when no-cache "--no-cache")
-			     (unless (string= "" search) search)))
+			     (unless (string-empty-p search) search)))
 
 (defface nix-search-pname
   '((t :height 1.5

nix-store.el

@@ -22,8 +22,9 @@
   :group 'nix)
 
 (defcustom nix-store-path-omit-self t
-  "Do not list the current entry itself within sections of nix-store-path-mode."
-  :package-version '(nix-mode . "1.6.0"))
+  "Do not list the current entry itself within sections of `nix-store-path-mode'."
+  :package-version '(nix-mode . "1.6.0")
+  :type 'boolean)
 
 (defun nix-store-realise (path)
   "Realise a path asynchronously.