PATCH: ancient history bug

[Peter Stephenson <p.w.stephenson@xxxxxxxxxxxx>]

Adding some further history tests (which I'll get back to tomorrow), I
found this bug.  It's probably been there since I factored out the
input code from the history code --- predating the CVS archive.  So
!-history can't be *that* popular:

% print This is a mystery              
This is a mystery
% print !:3-$
print a mystery
a mystery
% print !:1-$
print a
a

Oops: the last word has gone.  Now you see it, now you

This is more fallout from the fact that aliases and history expansions
are handled in similar ways.  When ungetting a character we need to take
care when going back up the expansion stack to discriminate --- if we
hit the end of the word in an alias, we'll think we don't need to mark
it as a word for the history.

pws

diff --git a/Src/input.c b/Src/input.c
index 30970a0..4a5bf89 100644
--- a/Src/input.c
+++ b/Src/input.c
@@ -56,8 +56,9 @@
  * inpop(), which effectively flushes any unread input as well as restoring
  * the previous input state.
  *
- * The internal flag INP_ALCONT shows that the stack element was pushed
- * by an alias expansion; it should not be needed elsewhere.
+ * The internal flags INP_ALCONT and INP_HISTCONT show that the stack
+ * element was pushed by an alias or history expansion; they should not
+ * be needed elsewhere.
  *
  * The global variable inalmore is set to indicate aliases should
  * continue to be expanded because the last alias expansion ended
@@ -446,7 +447,8 @@ inungetc(int c)
 	 * we may need to restore an alias popped from the stack.
 	 * Note this may be a dummy (history expansion) entry.
 	 */
-	if (inbufptr == inbufpush && inbufflags & INP_ALCONT) {
+	if (inbufptr == inbufpush &&
+	    (inbufflags & (INP_ALCONT|INP_HISTCONT))) {
 	    /*
 	     * Go back up the stack over all entries which were alias
 	     * expansions and were pushed with nothing remaining to read.
@@ -455,8 +457,12 @@ inungetc(int c)
 		if (instacktop->alias)
 		    instacktop->alias->inuse = 1;
 		instacktop++;
-	    } while ((instacktop->flags & INP_ALCONT) && !instacktop->bufleft);
-	    inbufflags = INP_CONT|INP_ALIAS;
+	    } while ((instacktop->flags & (INP_ALCONT|INP_HISTCONT))
+		     && !instacktop->bufleft);
+	    if (inbufflags & INP_HISTCONT)
+		inbufflags = INP_CONT|INP_ALIAS|INP_HIST;
+	    else
+		inbufflags = INP_CONT|INP_ALIAS;
 	    inbufleft = 0;
 	    inbuf = inbufptr = "";
 	}
@@ -522,7 +528,7 @@ inpush(char *str, int flags, Alias inalias)
     instacktop->bufptr = inbufptr;
     instacktop->bufleft = inbufleft;
     instacktop->bufct = inbufct;
-    inbufflags &= ~INP_ALCONT;
+    inbufflags &= ~(INP_ALCONT|INP_HISTCONT);
     if (flags & (INP_ALIAS|INP_HIST)) {
 	/*
 	 * Text is expansion for history or alias, so continue
@@ -531,7 +537,10 @@ inpush(char *str, int flags, Alias inalias)
 	 * and mark alias as in use.
 	 */
 	flags |= INP_CONT|INP_ALIAS;
-	instacktop->flags = inbufflags | INP_ALCONT;
+	if (flags & INP_HIST)
+	    instacktop->flags = inbufflags | INP_HISTCONT;
+	else
+	    instacktop->flags = inbufflags | INP_ALCONT;
 	if ((instacktop->alias = inalias))
 	    inalias->inuse = 1;
     } else {
@@ -570,7 +579,7 @@ static void
 inpoptop(void)
 {
     if (!lexstop) {
-	inbufflags &= ~INP_ALCONT;
+	inbufflags &= ~(INP_ALCONT|INP_HISTCONT);
 	while (inbufptr > inbuf) {
 	    inbufptr--;
 	    inbufct++;
@@ -598,7 +607,7 @@ inpoptop(void)
     inbufct = instacktop->bufct;
     inbufflags = instacktop->flags;
 
-    if (!(inbufflags & INP_ALCONT))
+    if (!(inbufflags & (INP_ALCONT|INP_HISTCONT)))
 	return;
 
     if (instacktop->alias) {
diff --git a/Src/zsh.h b/Src/zsh.h
index 403e8d3..486ad80 100644
--- a/Src/zsh.h
+++ b/Src/zsh.h
@@ -411,8 +411,9 @@ enum {
 #define INP_HIST      (1<<2)	/* expanding history                       */
 #define INP_CONT      (1<<3)	/* continue onto previously stacked input  */
 #define INP_ALCONT    (1<<4)	/* stack is continued from alias expn.     */
-#define INP_LINENO    (1<<5)    /* update line number                      */
-#define INP_APPEND    (1<<6)    /* Append new lines to allow backup        */
+#define INP_HISTCONT  (1<<5)	/* stack is continued from history expn.   */
+#define INP_LINENO    (1<<6)    /* update line number                      */
+#define INP_APPEND    (1<<7)    /* Append new lines to allow backup        */
 
 /* Flags for metafy */
 #define META_REALLOC	0