PATCH: Removing aliases from history, 2015 style (was capturing output of !! not working)

[Peter Stephenson <p.stephenson@samsung.com>]

On Mon, 23 Mar 2015 21:34:26 +0000
Peter Stephenson <p.w.stephenson@ntlworld.com> wrote:
> Ideally, I think we'd handle not adding
> the alias text to history the way we've been doing in other cases by
> checking INP_* flags, which is much less hit and miss.  That ought not
> to be too difficult, but I haven't really got my mind round the
> consequences yet.

Hmm... I typed this in more or less as below (with one subsequent fix to
testing flags for interaction with !-history) and was expecting it to
fail horribly, and so far it's failed to fail.  Perhaps my expectations
were low simply because it's been the old way since 2 million BC.

I'll try it further.

Obviously this doesn't change the fact that "{bar" turns into "echobar"
for execution after alias expansion (it no longer does so in the history),
since that's up in the lexer.

Some more tidying up may now be possible given that removing aliases
from history is less of a special case.

hwget() had a special hack for aliases, which I don't think should be
needed now, but I'd like to know --- the DEBUG code should tell us if
something nasty is happening.

pws

diff --git a/Src/hist.c b/Src/hist.c
index b44f4ad..990e609 100644
--- a/Src/hist.c
+++ b/Src/hist.c
@@ -245,7 +245,6 @@ hist_context_save(struct hist_stack *hs, int toplevel)
     hs->chwords = chwords;
     hs->chwordlen = chwordlen;
     hs->chwordpos = chwordpos;
-    hs->hwgetword = hwgetword;
     hs->hgetc = hgetc;
     hs->hungetc = hungetc;
     hs->hwaddc = hwaddc;
@@ -289,7 +288,6 @@ hist_context_restore(const struct hist_stack *hs, int toplevel)
     chwords = hs->chwords;
     chwordlen = hs->chwordlen;
     chwordpos = hs->chwordpos;
-    hwgetword = hs->hwgetword;
     hgetc = hs->hgetc;
     hungetc = hs->hungetc;
     hwaddc = hs->hwaddc;
@@ -338,8 +336,7 @@ ihwaddc(int c)
 	 * fashion as we never need the expansion in the history
 	 * line, only in the lexer and above.
 	 */
-	!((histactive & HA_INWORD) &&
-	  (inbufflags & (INP_ALIAS|INP_HIST)) == INP_ALIAS)) {
+	(inbufflags & (INP_ALIAS|INP_HIST)) != INP_ALIAS) {
 	/* Quote un-expanded bangs in the history line. */
 	if (c == bangchar && stophist < 2 && qbang)
 	    /* If qbang is not set, we do not escape this bangchar as it's *
@@ -915,8 +912,7 @@ ihungetc(int c)
 	    zlemetall--;
 	    exlast++;
 	}
-	if (!(histactive & HA_INWORD) ||
-	    (inbufflags & (INP_ALIAS|INP_HIST)) != INP_ALIAS) {
+	if ((inbufflags & (INP_ALIAS|INP_HIST)) != INP_ALIAS) {
 	    DPUTS(hptr <= chline, "BUG: hungetc attempted at buffer start");
 	    hptr--;
 	    DPUTS(*hptr != (char) c, "BUG: wrong character in hungetc() ");
@@ -1536,28 +1532,17 @@ hend(Eprog prog)
     return !(flag & HISTFLAG_NOEXEC || errflag);
 }
 
-/* Gives current expansion word if not last word before chwordpos. */
-
-/**/
-int hwgetword = -1;
-
 /* begin a word */
 
 /**/
 void
 ihwbegin(int offset)
 {
-    if (stophist == 2 || (histactive & HA_INWORD))
+    if (stophist == 2 || (histactive & HA_INWORD) ||
+	(inbufflags & (INP_ALIAS|INP_HIST)) == INP_ALIAS)
 	return;
     if (chwordpos%2)
 	chwordpos--;	/* make sure we're on a word start, not end */
-    /* If we're expanding an alias, we should overwrite the expansion
-     * in the history.
-     */
-    if ((inbufflags & INP_ALIAS) && !(inbufflags & INP_HIST))
-	hwgetword = chwordpos;
-    else
-	hwgetword = -1;
     chwords[chwordpos++] = hptr - chline + offset;
 }
 
@@ -1567,7 +1552,8 @@ ihwbegin(int offset)
 void
 ihwend(void)
 {
-    if (stophist == 2 || (histactive & HA_INWORD))
+    if (stophist == 2 || (histactive & HA_INWORD) ||
+	(inbufflags & (INP_ALIAS|INP_HIST)) == INP_ALIAS)
 	return;
     if (chwordpos%2 && chline) {
 	/* end of word reached and we've already begun a word */
@@ -1578,13 +1564,6 @@ ihwend(void)
 					    (chwordlen += 32) * 
 					    sizeof(short));
 	    }
-	    if (hwgetword > -1 &&
-		(inbufflags & INP_ALIAS) && !(inbufflags & INP_HIST)) {
-		/* We want to reuse the current word position */
-		chwordpos = hwgetword;
-		/* Start from where previous word ended, if possible */
-		hptr = chline + chwords[chwordpos ? chwordpos - 1 : 0];
-	    }
 	} else {
 	    /* scrub that last word, it doesn't exist */
 	    chwordpos--;
@@ -1608,17 +1587,17 @@ histbackword(void)
 static void
 hwget(char **startptr)
 {
-    int pos = hwgetword > -1 ? hwgetword : chwordpos - 2;
+    int pos = chwordpos - 2;
 
 #ifdef DEBUG
     /* debugging only */
-    if (hwgetword == -1 && !chwordpos) {
+    if (!chwordpos) {
 	/* no words available */
 	DPUTS(1, "BUG: hwget() called with no words");
 	*startptr = "";
 	return;
-    } 
-    else if (hwgetword == -1 && chwordpos%2) {
+    }
+    else if (chwordpos%2) {
 	DPUTS(1, "BUG: hwget() called in middle of word");
 	*startptr = "";
 	return;
@@ -1640,9 +1619,9 @@ hwrep(char *rep)
 
     if (!strcmp(rep, start))
 	return;
-    
+
     hptr = start;
-    chwordpos = (hwgetword > -1) ? hwgetword : chwordpos - 2;
+    chwordpos = chwordpos - 2;
     hwbegin(0);
     qbang = 1;
     while (*rep)
@@ -1670,7 +1649,6 @@ hgetline(void)
     /* reset line */
     hptr = chline;
     chwordpos = 0;
-    hwgetword = -1;
 
     return ret;
 }
diff --git a/Src/zsh.h b/Src/zsh.h
index 9a97263..403e8d3 100644
--- a/Src/zsh.h
+++ b/Src/zsh.h
@@ -2709,7 +2709,6 @@ struct hist_stack {
     short *chwords;
     int chwordlen;
     int chwordpos;
-    int hwgetword;
     int (*hgetc) _((void));
     void (*hungetc) _((int));
     void (*hwaddc) _((int));