Subject: 25.0.95; read-string with HIST lexically bound

From: Tino Calancha <[email-masked]>
Date: Fri, 17 Jun 2016 14:19:02 +0900

Hello,

recently i have noticed that arg HIST in read-from-minibuffer/read-string
needs to be dynamically bound.  If the file has the local variable
lexical-binding non-nil those functions just pick up one element of HIST.

In case this is a feature, it would be worth to mention it on the manual.

Following example reproduce the issue:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

I)

Create two files 'test-dynamic.el', 'test-lexical.el'
as follows:

*) test-dynamic.el:
(defun my-test-dynamic ()
   "Test of dynamic-binding."
   (interactive)
   (let ((values '("a" "b" "c")))
     (read-string "dynamic: " (car values) '(values . 1))))

*) test-lexical.el:
;; -*- lexical-binding: t; -*-

(defvar my-test-var nil)

(defun my-test-lexical-defvar ()
   "Test of lexical-binding with defvar."
   (interactive)
     (let ((values '("a" "b" "c")))
       (setq my-test-var values))
     (read-string "lexical-defvar: " (car my-test-var) '(my-test-var . 1)))

(defun my-test-lexical ()
   "Test of lexical-binding."
   (interactive)
   (let ((values '("a" "b" "c")))
     (read-string "lexical: " (car values) '(values . 1))))

II)
emacs -Q -l test-dynamic.el -l test-lexical.el

II.1)

M-x my-test-dynamic RET
;; minibuffer shows: dynamic: a
M-p
;; minibuffer shows: dynamic: b
M-p
;; minibuffer shows: dynamic: c

II.2) (Similar than II.1)

M-x my-test-lexical-defvar RET
;; minibuffer shows: lexical-defvar: a
M-p
;; minibuffer shows: lexical-defvar: b
M-p
;; minibuffer shows: lexical-defvar: c

II.3) (Different)
M-x my-test-lexical RET
;; minibuffer shows: lexical: a
M-p
;; user-error: Beginning of history; no preceding item

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

In GNU Emacs 25.0.95.1 (x86_64-pc-linux-gnu, GTK+ Version 3.20.6)
  of 2016-06-15 built on calancha-pc
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