bug#29923: [PATCH] Skip writing empty abbrev tables

[Allen Li <vianchielfaura@gmail.com>]

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Patch attached

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From fa3e3ed1f55fd2d973826dbd21b5b59072b86504 Mon Sep 17 00:00:00 2001
From: Allen Li <darkfeline@felesatra.moe>
Date: Sun, 31 Dec 2017 20:33:21 -0800
Subject: [PATCH] Skip writing empty abbrev tables

Fixes bug#29923

* lisp/abbrev.el (write-abbrev-file): Pass SKIPEMPTY to
insert-abbrev-table-description.
(insert-abbrev-table-description): Add SKIPEMPTY optional
parameter. Skip inserting empty tables if SKIPEMPTY is non-nil.
---
 lisp/abbrev.el | 46 ++++++++++++++++++++++++++--------------------
 1 file changed, 26 insertions(+), 20 deletions(-)

diff --git a/lisp/abbrev.el b/lisp/abbrev.el
index 5faffd4e17..9ba114e6a0 100644
--- a/lisp/abbrev.el
+++ b/lisp/abbrev.el
@@ -34,6 +34,7 @@
 
 (eval-when-compile (require 'cl-lib))
 (require 'obarray)
+(require 'seq)
 
 (defgroup abbrev-mode nil
   "Word abbreviations mode."
@@ -254,7 +255,7 @@ write-abbrev-file
 		     (lambda (s1 s2)
 		       (string< (symbol-name s1)
 				(symbol-name s2)))))
-	(insert-abbrev-table-description table nil))
+	(insert-abbrev-table-description table nil t))
       (when (unencodable-char-position (point-min) (point-max) 'utf-8)
 	(setq coding-system-for-write
 	      (if (> emacs-major-version 24)
@@ -933,35 +934,40 @@ abbrev--describe
       (prin1 (symbol-function sym)))
     (terpri)))
 
-(defun insert-abbrev-table-description (name &optional readable)
+(defun insert-abbrev-table-description (name &optional readable skipempty)
   "Insert before point a full description of abbrev table named NAME.
 NAME is a symbol whose value is an abbrev table.
 If optional 2nd arg READABLE is non-nil, a human-readable description
 is inserted.  Otherwise the description is an expression,
 a call to `define-abbrev-table', which would
 define the abbrev table NAME exactly as it is currently defined.
+If optional arg SKIPEMPTY is non-nil, skip insertion if table is empty.
 
 Abbrevs marked as \"system abbrevs\" are omitted."
   (let ((table (symbol-value name))
         (symbols ()))
-    (mapatoms (lambda (sym) (if (symbol-value sym) (push sym symbols))) table)
-    (setq symbols (sort symbols 'string-lessp))
-    (let ((standard-output (current-buffer)))
-      (if readable
-	  (progn
-	    (insert "(")
-	    (prin1 name)
-	    (insert ")\n\n")
-	    (mapc 'abbrev--describe symbols)
-	    (insert "\n\n"))
-	(insert "(define-abbrev-table '")
-	(prin1 name)
-	(if (null symbols)
-	    (insert " '())\n\n")
-	  (insert "\n  '(\n")
-	  (mapc 'abbrev--write symbols)
-	  (insert "   ))\n\n")))
-      nil)))
+    (mapatoms (lambda (sym)
+                (if (and (symbol-value sym) (not (abbrev-get sym :system)))
+                    (push sym symbols)))
+              table)
+    (when (or symbols (not skipempty))
+      (setq symbols (sort symbols 'string-lessp))
+      (let ((standard-output (current-buffer)))
+        (if readable
+            (progn
+              (insert "(")
+              (prin1 name)
+              (insert ")\n\n")
+              (mapc 'abbrev--describe symbols)
+              (insert "\n\n"))
+          (insert "(define-abbrev-table '")
+          (prin1 name)
+          (if (null symbols)
+              (insert " '())\n\n")
+            (insert "\n  '(\n")
+            (mapc 'abbrev--write symbols)
+            (insert "   ))\n\n")))
+        nil))))
 
 (defun define-abbrev-table (tablename definitions
                                       &optional docstring &rest props)
-- 
2.15.1