41164: Don't free a history entry if it's curline.

This replaces 41113 / 94014ff65b with a simple local change for the
immediate problem.  It's not entirely clear if this reflects wider
changes in the structure of the history code.

4 files changed, 23 insertions, 29 deletions

diff --git a/ChangeLog b/ChangeLog
index eb1af3488..03592c04d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2017-05-26  Peter Stephenson  <p.stephenson@samsung.com>
+
+	* 41164: Src/hashtable.c, Src/hist.c, Src/zsh.h: Don't free a
+	history entry if it's the current line.  This replaces 41113.
+
 2017-05-28  Barton E. Schaefer  <schaefer@zsh.org>
 
 	* Sebastian: 41153: Src/Modules/db_gdbm.c: finish module setup
diff --git a/Src/hashtable.c b/Src/hashtable.c
index c34744cd8..6ec2ed220 100644
--- a/Src/hashtable.c
+++ b/Src/hashtable.c
@@ -1445,10 +1445,12 @@ freehistdata(Histent he, int unlink)
     if (!he)
 	return;
 
+    if (he == &curline)
+	return;
+
     if (!(he->node.flags & (HIST_DUP | HIST_TMPSTORE)))
 	removehashnode(histtab, he->node.nam);
 
-    DPUTS(he->node.nam == chline, "Attempt to free chline in history data");
     zsfree(he->node.nam);
     if (he->nwords)
 	zfree(he->words, he->nwords*2*sizeof(short));
diff --git a/Src/hist.c b/Src/hist.c
index 4c1039b67..350688d2d 100644
--- a/Src/hist.c
+++ b/Src/hist.c
@@ -87,9 +87,6 @@ mod_export zlong curhist;
 /**/
 struct histent curline;
 
-/***/
-int curline_linked;
-
 /* current line count of allocated history entries */
 
 /**/
@@ -264,9 +261,6 @@ hist_context_save(struct hist_stack *hs, int toplevel)
      */
     hs->cstack = cmdstack;
     hs->csp = cmdsp;
-    hs->curline_linked = curline_linked;
-
-    unlinkcurline();
 
     stophist = 0;
     chline = NULL;
@@ -306,9 +300,6 @@ hist_context_restore(const struct hist_stack *hs, int toplevel)
 	zfree(cmdstack, CMDSTACKSZ);
     cmdstack = hs->cstack;
     cmdsp = hs->csp;
-    unlinkcurline();
-    if (hs->curline_linked)
-	linkcurline();
 }
 
 /*
@@ -999,7 +990,6 @@ nohwe(void)
 
 /* these functions handle adding/removing curline to/from the hist_ring */
 
-/**/
 static void
 linkcurline(void)
 {
@@ -1012,15 +1002,11 @@ linkcurline(void)
 	hist_ring = &curline;
     }
     curline.histnum = ++curhist;
-    curline_linked = 1;
 }
 
-/**/
 static void
 unlinkcurline(void)
 {
-    if (!curline_linked)
-	return;
     curline.up->down = curline.down;
     curline.down->up = curline.up;
     if (hist_ring == &curline) {
@@ -1030,7 +1016,6 @@ unlinkcurline(void)
 	    hist_ring = curline.up;
     }
     curhist--;
-    curline_linked = 0;
 }
 
 /* initialize the history mechanism */
@@ -1050,7 +1035,6 @@ hbegin(int dohist)
 	stophist = (!interact || unset(SHINSTDIN)) ? 2 : 0;
     else
 	stophist = 0;
-    DPUTS(chline != NULL, "chline set at start of history");
     /*
      * pws: We used to test for "|| (inbufflags & INP_ALIAS)"
      * in this test, but at this point we don't have input
@@ -1308,10 +1292,11 @@ putoldhistentryontop(short keep_going)
 Histent
 prepnexthistent(void)
 {
-    Histent he;
-    int relink_curline = curline_linked;
+    Histent he; 
+    int curline_in_ring = hist_ring == &curline;
 
-    unlinkcurline();
+    if (curline_in_ring)
+	unlinkcurline();
     if (hist_ring && hist_ring->node.flags & HIST_TMPSTORE) {
 	curhist--;
 	freehistnode(&hist_ring->node);
@@ -1335,7 +1320,7 @@ prepnexthistent(void)
 	he = hist_ring;
     }
     he->histnum = ++curhist;
-    if (relink_curline)
+    if (curline_in_ring)
 	linkcurline();
     return he;
 }
@@ -1410,7 +1395,8 @@ hend(Eprog prog)
     queue_signals();
     if (histdone & HISTFLAG_SETTY)
 	settyinfo(&shttyinfo);
-    unlinkcurline();
+    if (!(histactive & HA_NOINC))
+	unlinkcurline();
     if (histactive & HA_NOINC) {
 	zfree(chline, hlinesz);
 	zfree(chwords, chwordlen*sizeof(short));
@@ -3638,7 +3624,7 @@ int
 pushhiststack(char *hf, zlong hs, zlong shs, int level)
 {
     struct histsave *h;
-    int relink_curline = curline_linked;
+    int curline_in_ring = (histactive & HA_ACTIVE) && hist_ring == &curline;
 
     if (histsave_stack_pos == histsave_stack_size) {
 	histsave_stack_size += 5;
@@ -3646,7 +3632,8 @@ pushhiststack(char *hf, zlong hs, zlong shs, int level)
 			    histsave_stack_size * sizeof (struct histsave));
     }
 
-    unlinkcurline();
+    if (curline_in_ring)
+	unlinkcurline();
 
     h = &histsave_stack[histsave_stack_pos++];
 
@@ -3681,7 +3668,7 @@ pushhiststack(char *hf, zlong hs, zlong shs, int level)
     savehistsiz = shs;
     inithist(); /* sets histtab */
 
-    if (relink_curline)
+    if (curline_in_ring)
 	linkcurline();
 
     return histsave_stack_pos;
@@ -3693,12 +3680,13 @@ int
 pophiststack(void)
 {
     struct histsave *h;
-    int relink_curline = curline_linked;
+    int curline_in_ring = (histactive & HA_ACTIVE) && hist_ring == &curline;
 
     if (histsave_stack_pos == 0)
 	return 0;
 
-    unlinkcurline();
+    if (curline_in_ring)
+	unlinkcurline();
 
     deletehashtable(histtab);
     zsfree(lasthist.text);
@@ -3721,7 +3709,7 @@ pophiststack(void)
     histsiz = h->histsiz;
     savehistsiz = h->savehistsiz;
 
-    if (relink_curline)
+    if (curline_in_ring)
 	linkcurline();
 
     return histsave_stack_pos + 1;
diff --git a/Src/zsh.h b/Src/zsh.h
index 405b27490..22f73f806 100644
--- a/Src/zsh.h
+++ b/Src/zsh.h
@@ -2931,7 +2931,6 @@ struct hist_stack {
     void (*addtoline) _((int));
     unsigned char *cstack;
     int csp;
-    int curline_linked;
 };
 
 /*