Re: vanishing history

[Wayne Davison <wayned@users.sourceforge.net>]

On Wed, 28 Nov 2001, Adam Spiers wrote:
> Does anyone have any idea why my .zshhistory occasionally looses the
> vast majority of its contents?  I can't reproduce it, so I can't begin
> to track down what's going on.

I've seen this from time to time, but also have been unable to reproduce
it.  In pouring over the code I did finally see one potential way that
the loss of contents could happen: if the history file is locked by
another process while we're trying to rewrite it.  Here's the fix (which
causes us to just punt on the rewrite if we read nothing):

Index: Src/hist.c
--- Src/hist.c	16 Feb 2002 09:15:07 -0000	1.39
+++ Src/hist.c	16 Feb 2002 09:21:16 -0000
@@ -2083,7 +2083,8 @@
 	    hist_ignore_all_dups |= isset(HISTSAVENODUPS);
 	    readhistfile(fn, err, 0);
 	    hist_ignore_all_dups = isset(HISTIGNOREALLDUPS);
-	    savehistfile(fn, err, 0);
+	    if (histlinect)
+		savehistfile(fn, err, 0);
 	    deletehashtable(histtab);

 	    curhist = remember_curhist;

..wayne..