bug#35277: 26.1.90; Non-assigned variable used in condition

bug#35277: 26.1.90; Non-assigned variable used in condition

[Óscar Fuentes]

../../emacs/src/widget.c: In function ‘EmacsFrameQueryGeometry’:
../../emacs/src/widget.c:457:29: warning: ‘ok_height’ may be used uninitialized in this function [-Wmaybe-uninitialized]
       if ((mask & CWHeight) && (ok_height != request->height))
           ~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../emacs/src/widget.c:455:18: warning: ‘ok_width’ may be used uninitialized in this function [-Wmaybe-uninitialized]
    result->width = ok_width;
    ~~~~~~~~~~~~~~^~~~~~~~~~

I checked that the warnings are legit. With

(setq frame-resize-pixelwise t)

ok_width is used in the `if'. Not ok_height, at least on my experiments,
but removing the warning would be nice.

Note that the warning for `ok_width' points to the assignment, but it is
used right before on the `if'.


In GNU Emacs 26.1.90 (build 2, x86_64-pc-linux-gnu, X toolkit)
 of 2019-03-16 built on sky
Repository revision: df7ed10e4f15d3ea8b4426f7721bafe60bf8deeb
Windowing system distributor 'The X.Org Foundation', version 11.0.12003000
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bug#35277: 26.1.90; Non-assigned variable used in condition

[Paul Eggert]

[-- Attachment #1: Type: text/plain, Size: 77 bytes --]

Thanks for reporting that. I installed the attached patch into Emacs master.

[-- Attachment #2: 0001-Fix-uninit-var-in-widget.c.patch --]
[-- Type: text/x-patch, Size: 1621 bytes --]

From debaa72dd89eee0dffc930a7ccff742ca5a81d88 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Mon, 15 Apr 2019 20:53:13 -0700
Subject: [PATCH] Fix uninit var in widget.c

* src/widget.c (EmacsFrameQueryGeometry):
Avoid use of uninitialized variables ok_width, ok_height (Bug#35277).
---
 src/widget.c | 21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

diff --git a/src/widget.c b/src/widget.c
index 508974dd46..e662dd3ecd 100644
--- a/src/widget.c
+++ b/src/widget.c
@@ -434,21 +434,20 @@ EmacsFrameResize (Widget widget)
 }
 
 static XtGeometryResult
-EmacsFrameQueryGeometry (Widget widget, XtWidgetGeometry *request, XtWidgetGeometry *result)
+EmacsFrameQueryGeometry (Widget widget, XtWidgetGeometry *request,
+			 XtWidgetGeometry *result)
 {
-  EmacsFrame ew = (EmacsFrame) widget;
-
   int mask = request->request_mode;
-  Dimension ok_width, ok_height;
 
-  if (mask & (CWWidth | CWHeight))
+  if (mask & (CWWidth | CWHeight) && !frame_resize_pixelwise)
     {
-      if (!frame_resize_pixelwise)
-	round_size_to_char (ew,
-			    (mask & CWWidth) ? request->width : ew->core.width,
-			    ((mask & CWHeight) ? request->height
-			     : ew->core.height),
-			    &ok_width, &ok_height);
+      EmacsFrame ew = (EmacsFrame) widget;
+      Dimension ok_width, ok_height;
+
+      round_size_to_char (ew,
+			  mask & CWWidth ? request->width : ew->core.width,
+			  mask & CWHeight ? request->height : ew->core.height,
+			  &ok_width, &ok_height);
       if ((mask & CWWidth) && (ok_width != request->width))
 	{
 	  result->request_mode |= CWWidth;
-- 
2.17.1