bug#53242: [PATCH] unify reads from local_var_alist

[Sergey Vinokurov <serg.foo@gmail.com>]

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Hello,

I've noticed that local_var_alist field of the buffer structure is 
accessed inconsistently. Sometimes it's Fassoc, sometimes it's Fassq and 
other times it's assq_no_quit and even an explicit loop.

I think it's safe to unify all the accesses via assq_no_quit since it's 
an internaly maintained alist that definitely has no cycles and elements 
are cons cells with symbol as their car.

Sergey

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From 2ed2cbb91d5e09615ad6610810014198a269d539 Mon Sep 17 00:00:00 2001
From: Sergey Vinokurov <serg.foo@gmail.com>
Date: Fri, 14 Jan 2022 00:16:19 +0000
Subject: [PATCH] Unify getting of values from local_var_alist

---
 src/buffer.c |  2 +-
 src/data.c   | 16 ++++++----------
 2 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/src/buffer.c b/src/buffer.c
index 10ac91915c..a3091015d9 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -1247,7 +1247,7 @@ buffer_local_value (Lisp_Object variable, Lisp_Object buffer)
       { /* Look in local_var_alist.  */
 	struct Lisp_Buffer_Local_Value *blv = SYMBOL_BLV (sym);
 	XSETSYMBOL (variable, sym); /* Update In case of aliasing.  */
-	result = Fassoc (variable, BVAR (buf, local_var_alist), Qnil);
+	result = assq_no_quit (variable, BVAR (buf, local_var_alist));
 	if (!NILP (result))
 	  {
 	    if (blv->fwd.fwdptr)
diff --git a/src/data.c b/src/data.c
index 5d0790692b..f287c38fcd 100644
--- a/src/data.c
+++ b/src/data.c
@@ -2103,7 +2103,7 @@ DEFUN ("make-local-variable", Fmake_local_variable, Smake_local_variable,
 
   /* Make sure this buffer has its own value of symbol.  */
   XSETSYMBOL (variable, sym);	/* Update in case of aliasing.  */
-  tem = Fassq (variable, BVAR (current_buffer, local_var_alist));
+  tem = assq_no_quit (variable, BVAR (current_buffer, local_var_alist));
   if (NILP (tem))
     {
       if (let_shadows_buffer_binding_p (sym))
@@ -2183,7 +2183,7 @@ DEFUN ("kill-local-variable", Fkill_local_variable, Skill_local_variable,
 
   /* Get rid of this buffer's alist element, if any.  */
   XSETSYMBOL (variable, sym);	/* Propagate variable indirection.  */
-  tem = Fassq (variable, BVAR (current_buffer, local_var_alist));
+  tem = assq_no_quit (variable, BVAR (current_buffer, local_var_alist));
   if (!NILP (tem))
     bset_local_var_alist
       (current_buffer,
@@ -2224,7 +2224,7 @@ DEFUN ("local-variable-p", Flocal_variable_p, Slocal_variable_p,
     case SYMBOL_PLAINVAL: return Qnil;
     case SYMBOL_LOCALIZED:
       {
-	Lisp_Object tail, elt, tmp;
+	Lisp_Object tmp;
 	struct Lisp_Buffer_Local_Value *blv = SYMBOL_BLV (sym);
 	XSETBUFFER (tmp, buf);
 	XSETSYMBOL (variable, sym); /* Update in case of aliasing.  */
@@ -2232,13 +2232,9 @@ DEFUN ("local-variable-p", Flocal_variable_p, Slocal_variable_p,
 	if (EQ (blv->where, tmp)) /* The binding is already loaded.  */
 	  return blv_found (blv) ? Qt : Qnil;
 	else
-	  for (tail = BVAR (buf, local_var_alist); CONSP (tail); tail = XCDR (tail))
-	    {
-	      elt = XCAR (tail);
-	      if (EQ (variable, XCAR (elt)))
-		return Qt;
-	    }
-	return Qnil;
+	  return NILP (assq_no_quit (variable, BVAR (buf, local_var_alist)))
+	    ? Qnil
+	    : Qt;
       }
     case SYMBOL_FORWARDED:
       {
-- 
2.34.1