33876: etc.: Separate errors and keyboards interrupts

Combination of 12 commits from interrupt_abort branch.

Basic strategy is to introduce bits to errflag and to set and
reset them separately.

Remove interrupt status on return to main keymap.

Turn off ERRFLAG_INT for always block.

Restore bit thereafter: we probably need a new variable in order
to allow user interrupts to be reset in the always block.

Add TRY_BLOCK_INTERRUPT

This works the same as TRY_BLOCK_ERROR, but for a SIGINT, too.

Ensure propagation of SIGINT from exited job.

If received by foreground job, shell uses ERRFLAG_INT, not
ERRFLAG_ERROR, to set the new state.

Reset errflag before precmd()

Add always block in _main_completion to fix ZLS_COLORS

Ensures we get the right state of $ZLS_COLORS at the end of _main_complete
even if there's an interrupt.  However, the "right state" is a bit messy
as it depends on styles.

28 files changed, 273 insertions, 124 deletions

diff --git a/Src/Modules/zpty.c b/Src/Modules/zpty.c
index 63c79a731..7b6130c6f 100644
--- a/Src/Modules/zpty.c
+++ b/Src/Modules/zpty.c
@@ -308,7 +308,7 @@ newptycmd(char *nam, char *pname, char **args, int echo, int nblock)
 
     prog = parse_string(zjoin(args, ' ', 1), 0);
     if (!prog) {
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	scriptname = oscriptname;
 	ineval = oineval;
 	return 1;
diff --git a/Src/Modules/zutil.c b/Src/Modules/zutil.c
index 1cca0c4b8..c89495070 100644
--- a/Src/Modules/zutil.c
+++ b/Src/Modules/zutil.c
@@ -301,7 +301,8 @@ setstypat(Style s, char *pat, Patprog prog, char **vals, int eval)
 	int ef = errflag;
 
 	eprog = parse_string(zjoin(vals, ' ', 1), 0);
-	errflag = ef;
+	/* Keep any user interrupt error status */
+	errflag = ef | (errflag & ERRFLAG_INT);
 
 	if (!eprog)
 	{
@@ -394,10 +395,11 @@ evalstyle(Stypat p)
     unsetparam("reply");
     execode(p->eval, 1, 0, "style");
     if (errflag) {
-	errflag = ef;
+	/* Keep any user interrupt error status */
+	errflag = ef | (errflag & ERRFLAG_INT);
 	return NULL;
     }
-    errflag = ef;
+    errflag = ef | (errflag & ERRFLAG_INT);
 
     queue_signals();
     if ((ret = getaparam("reply")))
diff --git a/Src/Zle/compcore.c b/Src/Zle/compcore.c
index 35d410cc6..b0c6e06f8 100644
--- a/Src/Zle/compcore.c
+++ b/Src/Zle/compcore.c
@@ -1671,7 +1671,7 @@ set_comp_sep(void)
     noaliases = ona;
     strinend();
     inpop();
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     noerrs = ne;
     lexrestore();
     wb = owb;
diff --git a/Src/Zle/compctl.c b/Src/Zle/compctl.c
index 0b7a32445..d15c2d1b0 100644
--- a/Src/Zle/compctl.c
+++ b/Src/Zle/compctl.c
@@ -1879,7 +1879,7 @@ ccmakehookfn(UNUSED(Hookdef dummy), struct ccmakedat *dat)
 	if (!m || !(m = m->next))
 	    break;
 
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
     }
     redup(osi, 0);
     dat->lst = 1;
@@ -2121,7 +2121,7 @@ getreal(char *str)
     if (!errflag && nonempty(l) &&
 	((char *) peekfirst(l)) && ((char *) peekfirst(l))[0])
 	return dupstring(peekfirst(l));
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
 
     return dupstring(str);
 }
@@ -2599,7 +2599,7 @@ makecomplistlist(Compctl cc, char *s, int incmd, int compadd)
 	makecomplistflags(cc, s, incmd, compadd);
 
     /* Reset some information variables for the next try. */
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     offs = oloffs;
     wb = owb;
     we = owe;
@@ -2847,7 +2847,7 @@ sep_comp_string(char *ss, char *s, int noffs)
     noaliases = ona;
     strinend();
     inpop();
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     noerrs = ne;
     lexrestore();
     wb = owb;
@@ -3725,7 +3725,7 @@ makecomplistflags(Compctl cc, char *s, int incmd, int compadd)
 	noaliases = ona;
 	strinend();
 	inpop();
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	lexrestore();
 	/* Fine, now do full expansion. */
 	prefork(foo, 0);
diff --git a/Src/Zle/compresult.c b/Src/Zle/compresult.c
index fcceb670c..93438a053 100644
--- a/Src/Zle/compresult.c
+++ b/Src/Zle/compresult.c
@@ -1092,7 +1092,7 @@ do_single(Cmatch m)
 			noerrs = 1;
 			parsestr(p);
 			singsub(&p);
-			errflag = 0;
+			errflag &= ~ERRFLAG_ERROR;
 			noerrs = ne;
 		    }
 		} else {
diff --git a/Src/Zle/textobjects.c b/Src/Zle/textobjects.c
index 85d014b27..37d2c0ad9 100644
--- a/Src/Zle/textobjects.c
+++ b/Src/Zle/textobjects.c
@@ -275,7 +275,7 @@ selectargument(UNUSED(char **args))
     noaliases = ona;
     strinend();
     inpop();
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     noerrs = ne;
     lexrestore();
     zlemetacs = ocs;
diff --git a/Src/Zle/zle_hist.c b/Src/Zle/zle_hist.c
index 9f65994dc..88623bb3c 100644
--- a/Src/Zle/zle_hist.c
+++ b/Src/Zle/zle_hist.c
@@ -853,8 +853,10 @@ pushlineoredit(char **args)
 	free(zhline);
     }
     ret = pushline(args);
-    if (!isfirstln)
-	errflag = done = 1;
+    if (!isfirstln) {
+	errflag |= ERRFLAG_ERROR;
+	done = 1;
+    }
     clearlist = 1;
     return ret;
 }
diff --git a/Src/Zle/zle_keymap.c b/Src/Zle/zle_keymap.c
index 30d25ebaa..48f210c7e 100644
--- a/Src/Zle/zle_keymap.c
+++ b/Src/Zle/zle_keymap.c
@@ -504,6 +504,16 @@ mod_export void
 selectlocalmap(Keymap m)
 {
     localkeymap = m;
+    if (!m)
+    {
+	/*
+	 * No local keymap; so we are returning to the global map.  If
+	 * the user ^Ced in the local map, they probably just want to go
+	 * back to normal editing.  So remove the interrupt error
+	 * status.
+	 */
+	errflag &= ~ERRFLAG_INT;
+    }
 }
 
 /* Reopen the currently selected keymap, in case it got deleted.  This *
diff --git a/Src/Zle/zle_main.c b/Src/Zle/zle_main.c
index caa052b13..a2f48e13a 100644
--- a/Src/Zle/zle_main.c
+++ b/Src/Zle/zle_main.c
@@ -744,7 +744,7 @@ raw_getbyte(long do_keytmout, char *cptr)
 			}
 			if (errflag) {
 			    /* No sensible way of handling errors here */
-			    errflag = 0;
+			    errflag &= ~ERRFLAG_ERROR;
 			    /*
 			     * Paranoia: don't run the hooks again this
 			     * time.
@@ -882,7 +882,7 @@ getbyte(long do_keytmout, int *timeout)
 		die = 0;
 		if (!errflag && !retflag && !breaks && !exit_pending)
 		    continue;
-		errflag = 0;
+		errflag &= ~ERRFLAG_ERROR;
 		breaks = obreaks;
 		errno = old_errno;
 		return lastchar = EOF;
@@ -1075,7 +1075,7 @@ zlecore(void)
 		DECCS();
 	    handleundo();
 	} else {
-	    errflag = 1;
+	    errflag |= ERRFLAG_ERROR;
 	    break;
 	}
 #ifdef HAVE_POLL
@@ -1233,6 +1233,10 @@ zleread(char **lp, char **rp, int flags, int context, char *init, char *finish)
 
     zleactive = 1;
     resetneeded = 1;
+    /*
+     * Start of the main zle read.
+     * Fully reset error conditions, including user interrupt.
+     */
     errflag = retflag = 0;
     lastcol = -1;
     initmodifier(&zmod);
@@ -1658,7 +1662,7 @@ bin_vared(char *name, char **args, Options ops, UNUSED(int func))
     }
     if (!t || errflag) {
 	/* error in editing */
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	breaks = obreaks;
 	if (t)
 	    zsfree(t);
@@ -1778,7 +1782,7 @@ recursiveedit(UNUSED(char **args))
     zrefresh();
     zlecore();
 
-    locerror = errflag;
+    locerror = errflag ? 1 : 0;
     errflag = done = eofsent = 0;
 
     return locerror;
diff --git a/Src/Zle/zle_misc.c b/Src/Zle/zle_misc.c
index d432acf7b..23286fc20 100644
--- a/Src/Zle/zle_misc.c
+++ b/Src/Zle/zle_misc.c
@@ -1041,7 +1041,7 @@ copyprevshellword(UNUSED(char **args))
 int
 sendbreak(UNUSED(char **args))
 {
-    errflag = 1;
+    errflag |= ERRFLAG_ERROR;
     return 1;
 }
 
diff --git a/Src/Zle/zle_tricky.c b/Src/Zle/zle_tricky.c
index b15d91c8e..864f804b7 100644
--- a/Src/Zle/zle_tricky.c
+++ b/Src/Zle/zle_tricky.c
@@ -829,7 +829,7 @@ docomplete(int lst)
 	    if (olst == COMP_EXPAND_COMPLETE &&
 		!strcmp(ol, zlemetaline)) {
 		zlemetacs = ocs;
-		errflag = 0;
+		errflag &= ~ERRFLAG_ERROR;
 
 		if (!compfunc) {
 		    char *p;
@@ -877,6 +877,19 @@ docomplete(int lst)
 
     active = 0;
     makecommaspecial(0);
+
+    /*
+     * As a special case, we reset user interrupts here.
+     * That's because completion is an intensive piece of
+     * computation that the user might want to interrupt separately
+     * from anything else going on.  If they do, they probably
+     * want to keep the line edit buffer intact.
+     *
+     * There's a race here that the user might hit ^C just
+     * after completion exited anyway, but that's inevitable.
+     */
+    errflag &= ~ERRFLAG_INT;
+
     return dat[1];
 }
 
@@ -1394,7 +1407,8 @@ get_comp_string(void)
     }
     strinend();
     inpop();
-    errflag = lexflags = 0;
+    lexflags = 0;
+    errflag &= ~ERRFLAG_ERROR;
     if (parbegin != -1) {
 	/* We are in command or process substitution if we are not in
 	 * a $((...)). */
@@ -2917,7 +2931,7 @@ getcurcmd(void)
     popheap();
     strinend();
     inpop();
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     unmetafy_line();
     lexrestore();
 
diff --git a/Src/Zle/zle_utils.c b/Src/Zle/zle_utils.c
index 08a32c30e..de91182b5 100644
--- a/Src/Zle/zle_utils.c
+++ b/Src/Zle/zle_utils.c
@@ -1715,7 +1715,8 @@ zlecallhook(char *name, char *arg)
     execzlefunc(thingy, args, 1);
     unrefthingy(thingy);
 
-    errflag = saverrflag;
+    /* Retain any user interrupt error status */
+    errflag = saverrflag | (errflag & ERRFLAG_INT);
     retflag = savretflag;
 }
 
diff --git a/Src/builtin.c b/Src/builtin.c
index c2af51f2e..ad3a1925f 100644
--- a/Src/builtin.c
+++ b/Src/builtin.c
@@ -422,7 +422,7 @@ execbuiltin(LinkList args, Builtin bn)
 	argc -= argv - argarr;
 
 	if (errflag) {
-	    errflag = 0;
+	    errflag &= ~ERRFLAG_ERROR;
 	    return 1;
 	}
 
@@ -3136,7 +3136,7 @@ bin_unset(char *name, char **argv, Options ops, int func)
 		    }
 		}
 		returnval = errflag;
-		errflag = 0;
+		errflag &= ~ERRFLAG_ERROR;
 	    } else {
 		zerrnam(name, "%s: invalid element for unset", s);
 		returnval = 1;
@@ -4242,7 +4242,7 @@ bin_print(char *name, char **args, Options ops, int func)
 		if (*argp) {
 		    width = (int)mathevali(*argp++);
 		    if (errflag) {
-			errflag = 0;
+			errflag &= ~ERRFLAG_ERROR;
 			ret = 1;
 		    }
 		}
@@ -4272,7 +4272,7 @@ bin_print(char *name, char **args, Options ops, int func)
 		    if (*argp) {
 			prec = (int)mathevali(*argp++);
 			if (errflag) {
-			    errflag = 0;
+			    errflag &= ~ERRFLAG_ERROR;
 			    ret = 1;
 			}
 		    }
@@ -4452,7 +4452,7 @@ bin_print(char *name, char **args, Options ops, int func)
 			zlongval = (curarg) ? mathevali(curarg) : 0;
 			if (errflag) {
 			    zlongval = 0;
-			    errflag = 0;
+			    errflag &= ~ERRFLAG_ERROR;
 			    ret = 1;
 			}
 			print_val(zlongval)
@@ -4481,7 +4481,7 @@ bin_print(char *name, char **args, Options ops, int func)
 			} else doubleval = 0;
 			if (errflag) {
 			    doubleval = 0;
-			    errflag = 0;
+			    errflag &= ~ERRFLAG_ERROR;
 			    ret = 1;
 			}
 			print_val(doubleval)
@@ -4494,7 +4494,7 @@ bin_print(char *name, char **args, Options ops, int func)
 			zulongval = (curarg) ? mathevali(curarg) : 0;
 			if (errflag) {
 			    zulongval = 0;
-			    errflag = 0;
+			    errflag &= ~ERRFLAG_ERROR;
 			    ret = 1;
 			}
 			print_val(zulongval)
@@ -4871,7 +4871,7 @@ zexit(int val, int from_where)
     in_exit = -1;
     /*
      * We want to do all remaining processing regardless of preceding
-     * errors.
+     * errors, even user interrupts.
      */
     errflag = 0;
 
@@ -5074,7 +5074,7 @@ eval(char **argv)
     if (fpushed)
 	funcstack = funcstack->prev;
 
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     scriptname = oscriptname;
     ineval = oineval;
 
@@ -6101,7 +6101,7 @@ bin_test(char *name, char **argv, UNUSED(Options ops), int func)
     condlex = zshlex;
 
     if (errflag) {
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	lexrestore();
 	return 1;
     }
@@ -6278,7 +6278,7 @@ bin_let(UNUSED(char *name), char **argv, UNUSED(Options ops), UNUSED(int func))
     while (*argv)
 	val = matheval(*argv++);
     /* Errors in math evaluation in let are non-fatal. */
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     /* should test for fabs(val.u.d) < epsilon? */
     return (val.type == MN_INTEGER) ? val.u.l == 0 : val.u.d == 0.0;
 }
diff --git a/Src/exec.c b/Src/exec.c
index a5f877191..6a7dbb1e1 100644
--- a/Src/exec.c
+++ b/Src/exec.c
@@ -59,7 +59,7 @@ mod_export int noerrs;
 /**/
 int nohistsave;
 
-/* error/break flag */
+/* error flag: bits from enum errflag_bits */
 
 /**/
 mod_export int errflag;
@@ -1601,7 +1601,8 @@ execpline(Estate state, wordcode slcode, int how, int last1)
 			    (killpg(jobtab[list_pipe_job].gleader, 0) == -1 ? 2 : 1);
 			list_pipe_pid = pid;
 			list_pipe_start = bgtime;
-			nowait = errflag = 1;
+			nowait = 1;
+			errflag |= ERRFLAG_ERROR;
 			breaks = loops;
 			close(synch[1]);
 			read_loop(synch[0], &dummy, 1);
@@ -1634,7 +1635,10 @@ execpline(Estate state, wordcode slcode, int how, int last1)
 			list_pipe_child = 1;
 			opts[INTERACTIVE] = 0;
 			if (errbrk_saved) {
-			    errflag = prev_errflag;
+			    /*
+			     * Keep any user interrupt bit in errflag.
+			     */
+			    errflag = prev_errflag | (errflag & ERRFLAG_INT);
 			    breaks = prev_breaks;
 			}
 			break;
@@ -1719,12 +1723,14 @@ execpline2(Estate state, wordcode pcode,
 
 	    if (pipe(synch) < 0) {
 		zerr("pipe failed: %e", errno);
-		lastval = errflag = 1;
+		lastval = 1;
+		errflag |= ERRFLAG_ERROR;
 		return;
 	    } else if ((pid = zfork(&bgtime)) == -1) {
 		close(synch[0]);
 		close(synch[1]);
-		lastval = errflag = 1;
+		lastval = 1;
+		errflag |= ERRFLAG_ERROR;
 		return;
 	    } else if (pid) {
 		char dummy, *text;
@@ -2560,7 +2566,8 @@ execcmd(Estate state, int input, int output, int how, int last1)
 		while (next && *next == '-' && strlen(next) >= 2) {
 		    if (!firstnode(args)) {
 			zerr("exec requires a command to execute");
-			errflag = lastval = 1;
+			lastval = 1;
+			errflag |= ERRFLAG_ERROR;
 			goto done;
 		    }
 		    uremnode(args, firstnode(args));
@@ -2577,12 +2584,14 @@ execcmd(Estate state, int input, int output, int how, int last1)
 			    } else {
 				if (!firstnode(args)) {
 				    zerr("exec requires a command to execute");
-				    errflag = lastval = 1;
+				    lastval = 1;
+				    errflag |= ERRFLAG_ERROR;
 				    goto done;
 				}
 				if (!nextnode(firstnode(args))) {
 				    zerr("exec flag -a requires a parameter");
-				    errflag = lastval = 1;
+				    lastval = 1;
+				    errflag |= ERRFLAG_ERROR;
 				    goto done;
 				}
 				exec_argv0 = (char *)
@@ -2598,7 +2607,8 @@ execcmd(Estate state, int input, int output, int how, int last1)
 			    break;
 			default:
 			    zerr("unknown exec flag -%c", *cmdopt);
-			    errflag = lastval = 1;
+			    lastval = 1;
+			    errflag |= ERRFLAG_ERROR;
 			    return;
 			}
 		    }
@@ -2661,7 +2671,8 @@ execcmd(Estate state, int input, int output, int how, int last1)
 		    } else if (!nullcmd || !*nullcmd || opts[CSHNULLCMD] ||
 			       (cflags & BINF_PREFIX)) {
 			zerr("redirection with no command");
-			errflag = lastval = 1;
+			lastval = 1;
+			errflag |= ERRFLAG_ERROR;
 			return;
 		    } else if (!nullcmd || !*nullcmd || opts[SHNULLCMD]) {
 			if (!args)
@@ -2691,7 +2702,7 @@ execcmd(Estate state, int input, int output, int how, int last1)
 		    if (varspc)
 			addvars(state, varspc, 0);
 		    if (errflag)
-			lastval = errflag;
+			lastval = 1;
 		    else
 			lastval = cmdoutval;
 		    if (isset(XTRACE)) {
@@ -2795,7 +2806,7 @@ execcmd(Estate state, int input, int output, int how, int last1)
 	    }
 	}
 	if (!nextnode(firstnode(args)))
-	    errflag = 1;
+	    errflag |= ERRFLAG_ERROR;
     }
 
     if (type == WC_FUNCDEF) {
@@ -2940,7 +2951,8 @@ execcmd(Estate state, int input, int output, int how, int last1)
 	} else if ((pid = zfork(&bgtime)) == -1) {
 	    close(synch[0]);
 	    close(synch[1]);
-	    lastval = errflag = 1;
+	    lastval = 1;
+	    errflag |= ERRFLAG_ERROR;
 	    goto fatal;
 	}
 	if (pid) {
@@ -3529,7 +3541,7 @@ execcmd(Estate state, int input, int output, int how, int last1)
 		else
 		    exit(1);
 	    }
-	    errflag = 1;
+	    errflag |= ERRFLAG_ERROR;
 	}
     }
     if (newxtrerr) {
@@ -3759,8 +3771,10 @@ gethere(char **strp, int typ)
 
 	parsestr(buf);
 
-	if (!errflag)
-	    errflag = ef;
+	if (!errflag) {
+	    /* Retain any user interrupt error */
+	    errflag = ef | (errflag & ERRFLAG_INT);
+	}
     }
     s = dupstring(buf);
     zfree(buf, bsiz);
@@ -3854,7 +3868,7 @@ getoutput(char *cmd, int qt)
 	return readoutput(stream, qt);
     }
     if (mpipe(pipes) < 0) {
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
 	cmdoutpid = 0;
 	return NULL;
     }
@@ -3864,7 +3878,7 @@ getoutput(char *cmd, int qt)
 	/* fork error */
 	zclose(pipes[0]);
 	zclose(pipes[1]);
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
 	cmdoutpid = 0;
 	child_unblock();
 	return NULL;
@@ -4274,7 +4288,7 @@ execcond(Estate state, UNUSED(int do_exec))
      * into a shell error.
      */
     if (stat == 2)
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
     cmdpop();
     if (isset(XTRACE)) {
 	fprintf(xtrerr, " ]]\n");
@@ -4314,7 +4328,7 @@ execarith(Estate state, UNUSED(int do_exec))
 	fflush(xtrerr);
     }
     if (errflag) {
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	return 2;
     }
     /* should test for fabs(val.u.d) < epsilon? */
@@ -4932,7 +4946,7 @@ doshfunc(Shfunc shfunc, LinkList doshargs, int noreturnval)
 						(name = fname)))) {
 	    zwarn("%s: function not defined by file", name);
 	    if (noreturnval)
-		errflag = 1;
+		errflag |= ERRFLAG_ERROR;
 	    else
 		lastval = 1;
 	    goto doneshfunc;
diff --git a/Src/glob.c b/Src/glob.c
index b3903f2ff..82f8d626c 100644
--- a/Src/glob.c
+++ b/Src/glob.c
@@ -682,7 +682,7 @@ parsecomplist(char *instr)
 	/* Now get the next path component if there is one. */
 	l1 = (Complist) zhalloc(sizeof *l1);
 	if ((l1->next = parsecomplist(instr)) == NULL) {
-	    errflag = 1;
+	    errflag |= ERRFLAG_ERROR;
 	    return NULL;
 	}
 	l1->pat = patcompile(NULL, compflags | PAT_ANY, NULL);
@@ -728,7 +728,7 @@ parsecomplist(char *instr)
 	    return (ef && !l1->next) ? NULL : l1;
 	}
     }
-    errflag = 1;
+    errflag |= ERRFLAG_ERROR;
     return NULL;
 }
 
@@ -1790,7 +1790,7 @@ zglob(LinkList list, LinkNode np, int nountok)
 	    insertlinknode(list, node, ostr);
 	    return;
 	}
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	zerr("bad pattern: %s", ostr);
 	return;
     }
@@ -1873,7 +1873,8 @@ zglob(LinkList list, LinkNode np, int nountok)
 				tmpptr->sortstrs[iexec] = tmpptr->name;
 			}
 
-			errflag = ef;
+			/* Retain any user interrupt error status */
+			errflag = ef | (errflag & ERRFLAG_INT);
 			lastval = lv;
 		    } else {
 			/* Failed, let's be safe */
@@ -3733,7 +3734,8 @@ qualsheval(char *name, UNUSED(struct stat *buf), UNUSED(off_t days), char *str)
 	execode(prog, 1, 0, "globqual");
 
 	ret = lastval;
-	errflag = ef;
+	/* Retain any user interrupt error status */
+	errflag = ef | (errflag & ERRFLAG_INT);
 	lastval = lv;
 
 	if (!(inserts = getaparam("reply")) &&
diff --git a/Src/hist.c b/Src/hist.c
index 7fe843a4a..a0061707c 100644
--- a/Src/hist.c
+++ b/Src/hist.c
@@ -287,7 +287,8 @@ ihgetc(void)
 	c = histsubchar(c);
 	if (c < 0) {
 	    /* bad expansion */
-	    errflag = lexstop = 1;
+	    lexstop = 1;
+	    errflag |= ERRFLAG_ERROR;
 	    return ' ';
 	}
     }
@@ -721,7 +722,7 @@ histsubchar(int c)
 		    noerrs = 1;
 		    parse_subst_string(sline);
 		    noerrs = one;
-		    errflag = oef;
+		    errflag = oef | (errflag & ERRFLAG_INT);
 		    remnulargs(sline);
 		    untokenize(sline);
 		}
@@ -880,7 +881,8 @@ hbegin(int dohist)
     char *hf;
 
     isfirstln = isfirstch = 1;
-    errflag = histdone = 0;
+    errflag &= ~ERRFLAG_ERROR;
+    histdone = 0;
     if (!dohist)
 	stophist = 2;
     else if (dohist != 2)
@@ -3182,7 +3184,7 @@ bufferwords(LinkList list, char *buf, int *index, int flags)
     noaliases = ona;
     strinend();
     inpop();
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     nocomments = onc;
     noerrs = ne;
     lexrestore();
diff --git a/Src/init.c b/Src/init.c
index 655166135..305908724 100644
--- a/Src/init.c
+++ b/Src/init.c
@@ -118,11 +118,24 @@ loop(int toplevel, int justonce)
 	    if (interact && toplevel) {
 	        int hstop = stophist;
 		stophist = 3;
+		/*
+		 * Reset all errors including the interrupt error status
+		 * immediately, so preprompt runs regardless of what
+		 * just happened.  We'll reset again below as a
+		 * precaution to ensure we get back to the command line
+		 * no matter what.
+		 */
+		errflag = 0;
 		preprompt();
 		if (stophist != 3)
 		    hbegin(1);
 		else
 		    stophist = hstop;
+		/*
+		 * Reset all errors, including user interupts.
+		 * This is what allows ^C in an interactive shell
+		 * to return us to the command line.
+		 */
 		errflag = 0;
 	    }
 	}
@@ -178,7 +191,15 @@ loop(int toplevel, int justonce)
 
 		/* The only permanent storage is from getpermtext() */
 		zsfree(cmdstr);
-		errflag = 0;
+		/*
+		 * Note this does *not* remove a user interrupt error
+		 * condition, even though we're at the top level loop:
+		 * that would be inconsistent with the case where
+		 * we didn't execute a preexec function.  This is
+		 * an implementation detail that an interrupting user
+		 * does't care about.
+		 */
+		errflag &= ~ERRFLAG_ERROR;
 	    }
 	    if (stopmsg)	/* unset 'you have stopped jobs' flag */
 		stopmsg--;
@@ -689,7 +710,7 @@ init_term(void)
     {
 	if (isset(INTERACTIVE))
 	    zerr("can't find terminal definition for %s", term);
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	termflags |= TERM_BAD;
 	return 0;
     } else {
@@ -1336,7 +1357,7 @@ source(char *s)
 
     if (prog) {
 	pushheap();
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	execode(prog, 1, 0, "filecode");
 	popheap();
 	if (errflag)
@@ -1379,7 +1400,7 @@ source(char *s)
     lineno = oldlineno;              /* our current lineno                   */
     loops = oloops;                  /* the # of nested loops we are in      */
     dosetopt(SHINSTDIN, oldshst, 1, opts); /* SHINSTDIN option               */
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     if (!exit_pending)
 	retflag = 0;
     scriptname = old_scriptname;
diff --git a/Src/input.c b/Src/input.c
index 4ac7e6ec8..9552331a9 100644
--- a/Src/input.c
+++ b/Src/input.c
@@ -291,7 +291,8 @@ inputline(void)
     }
     if (errflag) {
 	free(ingetcline);
-	return lexstop = errflag = 1;
+	errflag |= ERRFLAG_ERROR;
+	return lexstop = 1;
     }
     if (isset(VERBOSE)) {
 	/* Output the whole line read so far. */
diff --git a/Src/jobs.c b/Src/jobs.c
index 6663a40a6..a668b07e6 100644
--- a/Src/jobs.c
+++ b/Src/jobs.c
@@ -509,7 +509,7 @@ update_job(Job jn)
 			prev_errflag = errflag;
 		    }
 		    breaks = loops;
-		    errflag = 1;
+		    errflag |= ERRFLAG_INT;
 		    inerrflush();
 		}
 	    } else {
@@ -526,7 +526,7 @@ update_job(Job jn)
 	    prev_errflag = errflag;
 	}
 	breaks = loops;
-	errflag = 1;
+	errflag |= ERRFLAG_INT;
 	inerrflush();
     }
     if (somestopped && jn->stat & STAT_SUPERJOB)
@@ -581,7 +581,7 @@ update_job(Job jn)
 		    breaks = loops;
 	    } else {
 		breaks = loops;
-		errflag = 1;
+		errflag |= ERRFLAG_INT;
 	    }
 	    check_cursh_sig(sig);
 	}
@@ -1444,12 +1444,19 @@ zwaitjob(int job, int wait_cmd)
 		restore_queue_signals(q);
 		return 128 + last_signal;
 	    }
-	    /* Commenting this out makes ^C-ing a job started by a function
-	       stop the whole function again.  But I guess it will stop
-	       something else from working properly, we have to find out
-	       what this might be.  --oberon
+           /* Commenting this out makes ^C-ing a job started by a function
+              stop the whole function again.  But I guess it will stop
+              something else from working properly, we have to find out
+              what this might be.  --oberon
+
+	      When attempting to separate errors and interrupts, we
+	      assumed because of the previous comment it would be OK
+	      to remove ERRFLAG_ERROR and leave ERRFLAG_INT set, since
+	      that's the one related to ^C.  But that doesn't work.
+	      There's something more here we don't understand.  --pws
+
+           errflag = 0; */
 
-	    errflag = 0; */
 	    if (subsh) {
 		killjb(jn, SIGCONT);
 		jn->stat &= ~STAT_STOPPED;
diff --git a/Src/lex.c b/Src/lex.c
index b2a05448c..4addf8033 100644
--- a/Src/lex.c
+++ b/Src/lex.c
@@ -385,7 +385,7 @@ lexrestore(void)
     ecnfunc = ln->ecnfunc;
     hlinesz = ln->hlinesz;
     toklineno = ln->toklineno;
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     free(ln);
 
     unqueue_signals();
@@ -1737,7 +1737,8 @@ parse_subst_string(char *s)
     inpop();
     DPUTS(cmdsp, "BUG: parse_subst_string: cmdstack not empty.");
     lexrestore();
-    errflag = err;
+    /* Keep any interrupt error status */
+    errflag = err | (errflag & ERRFLAG_INT);
     if (ctok == LEXERR) {
 	untokenize(s);
 	return 1;
diff --git a/Src/loop.c b/Src/loop.c
index 82d2fe31a..8bb1ec9dd 100644
--- a/Src/loop.c
+++ b/Src/loop.c
@@ -259,7 +259,8 @@ execselect(Estate state, UNUSED(int do_exec))
 				   0, ZLCON_SELECT);
 		    if (errflag)
 			str = NULL;
-		    errflag = oef;
+		    /* Keep any user interrupt error status */
+		    errflag = oef | (errflag & ERRFLAG_INT);
 	    	} else {
 		    str = promptexpand(prompt3, 0, NULL, NULL, NULL);
 		    zputs(str, stderr);
@@ -632,6 +633,14 @@ execcase(Estate state, int do_exec)
 zlong
 try_errflag = -1;
 
+/**
+ * Corresponding interrupt error status form `try' block.
+ */
+
+/**/
+zlong
+try_interrupt = -1;
+
 /**/
 zlong
 try_tryflag = 0;
@@ -643,7 +652,7 @@ exectry(Estate state, int do_exec)
     Wordcode end, always;
     int endval;
     int save_retflag, save_breaks, save_contflag;
-    zlong save_try_errflag, save_try_tryflag;
+    zlong save_try_errflag, save_try_tryflag, save_try_interrupt;
 
     end = state->pc + WC_TRY_SKIP(state->pc[-1]);
     always = state->pc + 1 + WC_TRY_SKIP(*state->pc);
@@ -670,7 +679,10 @@ exectry(Estate state, int do_exec)
 
     /* The always clause. */
     save_try_errflag = try_errflag;
-    try_errflag = (zlong)errflag;
+    save_try_interrupt = try_interrupt;
+    try_errflag = (zlong)(errflag & ERRFLAG_ERROR);
+    try_interrupt = (zlong)((errflag & ERRFLAG_INT) ? 1 : 0);
+    /* We need to reset all errors to allow the block to execute */
     errflag = 0;
     save_retflag = retflag;
     retflag = 0;
@@ -682,8 +694,16 @@ exectry(Estate state, int do_exec)
     state->pc = always;
     execlist(state, 1, do_exec);
 
-    errflag = try_errflag ? 1 : 0;
+    if (try_errflag)
+	errflag |= ERRFLAG_ERROR;
+    else
+	errflag &= ~ERRFLAG_ERROR;
+    if (try_interrupt)
+	errflag |= ERRFLAG_INT;
+    else
+	errflag &= ~ERRFLAG_INT;
     try_errflag = save_try_errflag;
+    try_interrupt = save_try_interrupt;
     if (!retflag)
 	retflag = save_retflag;
     if (!breaks)
diff --git a/Src/params.c b/Src/params.c
index 61edc5d08..79088d162 100644
--- a/Src/params.c
+++ b/Src/params.c
@@ -331,6 +331,7 @@ IPDEF5("SHLVL", &shlvl, varinteger_gsu),
 #define IPDEF6(A,B,F) {{NULL,A,PM_INTEGER|PM_SPECIAL|PM_DONTIMPORT},BR((void *)B),GSU(F),10,0,NULL,NULL,NULL,0}
 IPDEF6("OPTIND", &zoptind, varinteger_gsu),
 IPDEF6("TRY_BLOCK_ERROR", &try_errflag, varinteger_gsu),
+IPDEF6("TRY_BLOCK_INTERRUPT", &try_interrupt, varinteger_gsu),
 
 #define IPDEF7(A,B) {{NULL,A,PM_SCALAR|PM_SPECIAL},BR((void *)B),GSU(varscalar_gsu),0,0,NULL,NULL,NULL,0}
 #define IPDEF7U(A,B) {{NULL,A,PM_SCALAR|PM_SPECIAL|PM_UNSET},BR((void *)B),GSU(varscalar_gsu),0,0,NULL,NULL,NULL,0}
@@ -2654,7 +2655,7 @@ assignsparam(char *s, char *val, int flags)
     if (!isident(s)) {
 	zerr("not an identifier: %s", s);
 	zsfree(val);
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
 	return NULL;
     }
     queue_signals();
@@ -2783,7 +2784,7 @@ assignaparam(char *s, char **val, int flags)
     if (!isident(s)) {
 	zerr("not an identifier: %s", s);
 	freearray(val);
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
 	return NULL;
     }
     queue_signals();
@@ -2799,7 +2800,7 @@ assignaparam(char *s, char **val, int flags)
 	    zerr("%s: attempt to set slice of associative array",
 		 v->pm->node.nam);
 	    freearray(val);
-	    errflag = 1;
+	    errflag |= ERRFLAG_ERROR;
 	    return NULL;
 	}
 	v = NULL;
@@ -2870,13 +2871,13 @@ sethparam(char *s, char **val)
     if (!isident(s)) {
 	zerr("not an identifier: %s", s);
 	freearray(val);
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
 	return NULL;
     }
     if (strchr(s, '[')) {
 	freearray(val);
 	zerr("nested associative arrays not yet supported");
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
 	return NULL;
     }
     if (unset(EXECOPT))
@@ -2916,7 +2917,7 @@ setnparam(char *s, mnumber val)
 
     if (!isident(s)) {
 	zerr("not an identifier: %s", s);
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
 	return NULL;
     }
     if (unset(EXECOPT))
diff --git a/Src/parse.c b/Src/parse.c
index 4ceeb4eaf..c1709e03a 100644
--- a/Src/parse.c
+++ b/Src/parse.c
@@ -71,13 +71,14 @@ struct heredocs *hdocs;
 
 #define YYERROR(O)  { tok = LEXERR; ecused = (O); return 0; }
 #define YYERRORV(O) { tok = LEXERR; ecused = (O); return; }
-#define COND_ERROR(X,Y) do { \
-  zwarn(X,Y); \
-  herrflush(); \
-  if (noerrs != 2) \
-    errflag = 1; \
-  YYERROR(ecused) \
-} while(0)
+#define COND_ERROR(X,Y) \
+    do {					\
+	zwarn(X,Y);				\
+	herrflush();				\
+	if (noerrs != 2)			\
+	    errflag |= ERRFLAG_ERROR;		\
+	YYERROR(ecused)				\
+	    } while(0)
 
 
 /* 
@@ -506,7 +507,7 @@ par_event(void)
 	yyerror(1);
 	herrflush();
 	if (noerrs != 2)
-	    errflag = 1;
+	    errflag |= ERRFLAG_ERROR;
 	ecused--;
 	return 0;
     } else {
@@ -2339,7 +2340,7 @@ yyerror(int noerr)
 	    zwarn("parse error");
     }
     if (!noerr && noerrs != 2)
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
 }
 
 /*
@@ -3031,7 +3032,7 @@ build_dump(char *nam, char *dump, char **files, int ali, int map, int flags)
 	file = metafy(file, flen, META_REALLOC);
 
 	if (!(prog = parse_string(file, 1)) || errflag) {
-	    errflag = 0;
+	    errflag &= ~ERRFLAG_ERROR;
 	    close(dfd);
 	    zfree(file, flen);
 	    zwarnnam(nam, "can't read file: %s", *files);
@@ -3141,7 +3142,7 @@ build_cur_dump(char *nam, char *dump, char **names, int match, int map,
 	    for (hn = shfunctab->nodes[i]; hn; hn = hn->next)
 		if (cur_add_func(nam, (Shfunc) hn, lnames, progs,
 				 &hlen, &tlen, what)) {
-		    errflag = 0;
+		    errflag &= ~ERRFLAG_ERROR;
 		    close(dfd);
 		    unlink(dump);
 		    return 1;
@@ -3166,7 +3167,7 @@ build_cur_dump(char *nam, char *dump, char **names, int match, int map,
 			pattry(pprog, hn->nam) &&
 			cur_add_func(nam, (Shfunc) hn, lnames, progs,
 				     &hlen, &tlen, what)) {
-			errflag = 0;
+			errflag &= ~ERRFLAG_ERROR;
 			close(dfd);
 			unlink(dump);
 			return 1;
@@ -3177,13 +3178,13 @@ build_cur_dump(char *nam, char *dump, char **names, int match, int map,
 	    if (errflag ||
 		!(shf = (Shfunc) shfunctab->getnode(shfunctab, *names))) {
 		zwarnnam(nam, "unknown function: %s", *names);
-		errflag = 0;
+		errflag &= ~ERRFLAG_ERROR;
 		close(dfd);
 		unlink(dump);
 		return 1;
 	    }
 	    if (cur_add_func(nam, shf, lnames, progs, &hlen, &tlen, what)) {
-		errflag = 0;
+		errflag &= ~ERRFLAG_ERROR;
 		close(dfd);
 		unlink(dump);
 		return 1;
@@ -3192,7 +3193,7 @@ build_cur_dump(char *nam, char *dump, char **names, int match, int map,
     }
     if (empty(progs)) {
 	zwarnnam(nam, "no functions");
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	close(dfd);
 	unlink(dump);
 	return 1;
diff --git a/Src/prompt.c b/Src/prompt.c
index 0cc9ef917..3552575f3 100644
--- a/Src/prompt.c
+++ b/Src/prompt.c
@@ -192,8 +192,11 @@ promptexpand(char *s, int ns, char *rs, char *Rs, unsigned int *txtchangep)
 	if (*s == Nularg && s[1] == '\0')
 	    *s = '\0';
 
-	/* Ignore errors and status change in prompt substitution */
-	errflag = olderr;
+	/*
+	 * Ignore errors and status change in prompt substitution.
+	 * However, keep any user interrupt error that occurred.
+	 */
+	errflag = olderr | (errflag & ERRFLAG_INT);
 	lastval = oldval;
     }
 
diff --git a/Src/signals.c b/Src/signals.c
index e72850516..899f1217b 100644
--- a/Src/signals.c
+++ b/Src/signals.c
@@ -619,7 +619,7 @@ zhandler(int sig)
 		zexit(SIGINT, 1);
             if (list_pipe || chline || simple_pline) {
                 breaks = loops;
-                errflag = 1;
+                errflag |= ERRFLAG_INT;
 		inerrflush();
 		check_cursh_sig(SIGINT);
             }
@@ -640,6 +640,11 @@ zhandler(int sig)
 	    if (idle >= 0 && idle < tmout)
 		alarm(tmout - idle);
 	    else {
+		/*
+		 * We want to exit now.
+		 * Cancel all errors, including a user interrupt
+		 * which is now redundant.
+		 */
 		errflag = noerrs = 0;
 		zwarn("timeout");
 		stopmsg = 1;
@@ -1267,7 +1272,18 @@ dotrapargs(int sig, int *sigtr, void *sigfn)
 	!(isfunc && new_trap_return == 0)) {
 	if (isfunc) {
 	    breaks = loops;
-	    errflag = 1;
+	    /*
+	     * For SIGINT we behave the same as the default behaviour
+	     * i.e. we set the error bit indicating an interrupt.
+	     * We do this with SIGQUIT, too, even though we don't
+	     * handle SIGQUIT by default.  That's to try to make
+	     * it behave a bit more like its normal behaviour when
+	     * the trap handler has told us that's what it wants.
+	     */
+	    if (sig == SIGINT || sig == SIGQUIT)
+		errflag |= ERRFLAG_INT;
+	    else
+		errflag |= ERRFLAG_ERROR;
 	}
 	lastval = new_trap_return;
 	/* return triggered */
@@ -1282,8 +1298,12 @@ dotrapargs(int sig, int *sigtr, void *sigfn)
 	     */
 	    lastval = olastval;
 	}
-	if (try_tryflag)
-	    errflag = traperr;
+	if (try_tryflag) {
+	    if (traperr)
+		errflag |= ERRFLAG_ERROR;
+	    else
+		errflag &= ~ERRFLAG_ERROR;
+	}
 	breaks += obreaks;
 	/* return not triggered: restore old flag */
 	retflag = oretflag;
diff --git a/Src/subst.c b/Src/subst.c
index 61aa1c136..43932c256 100644
--- a/Src/subst.c
+++ b/Src/subst.c
@@ -2822,7 +2822,8 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags)
 		haserr = parse_subst_string(s);
 		noerrs = one;
 		if (!quoteerr) {
-		    errflag = oef;
+		    /* Retain user interrupt error status */
+		    errflag = oef | (errflag & ERRFLAG_INT);
 		    if (haserr)
 			shtokenize(s);
 		} else if (haserr || errflag) {
@@ -3249,8 +3250,10 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags)
 		haserr = 1;
 	}
 	noerrs = one;
-	if (!quoteerr)
-	    errflag = oef;
+	if (!quoteerr) {
+	    /* Retain user interrupt error status */
+	    errflag = oef | (errflag & ERRFLAG_INT);
+	}
 	if (haserr || errflag)
 	    return NULL;
     }
@@ -3483,8 +3486,10 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags)
 		    untokenize(*ap);
 		}
 		noerrs = one;
-		if (!quoteerr)
-		    errflag = oef;
+		if (!quoteerr) {
+		    /* Retain any user interrupt error status */
+		    errflag = oef | (errflag & ERRFLAG_INT);
+		}
 		else if (haserr || errflag) {
 		    zerr("parse error in parameter value");
 		    return NULL;
@@ -3516,8 +3521,10 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags)
 		    noerrs = 1;
 		haserr = parse_subst_string(val);
 		noerrs = one;
-		if (!quoteerr)
-		    errflag = oef;
+		if (!quoteerr) {
+		    /* Retain any user interrupt error status */
+		    errflag = oef | (errflag & ERRFLAG_INT);
+		}
 		else if (haserr || errflag) {
 		    zerr("parse error in parameter value");
 		    return NULL;
@@ -4086,7 +4093,8 @@ modify(char **str, char **ptr)
 			    noerrs = 1;
 			    parse_subst_string(copy);
 			    noerrs = one;
-			    errflag = oef;
+			    /* Retain any user interrupt error status */
+			    errflag = oef | (errflag & ERRFLAG_INT);
 			    remnulargs(copy);
 			    untokenize(copy);
 			}
@@ -4161,7 +4169,8 @@ modify(char **str, char **ptr)
 			noerrs = 1;
 			parse_subst_string(*str);
 			noerrs = one;
-			errflag = oef;
+			/* Retain any user interrupt error status */
+			errflag = oef | (errflag & ERRFLAG_INT);
 			remnulargs(*str);
 			untokenize(*str);
 		    }
diff --git a/Src/utils.c b/Src/utils.c
index ab3d3da93..893a8ca02 100644
--- a/Src/utils.c
+++ b/Src/utils.c
@@ -153,7 +153,7 @@ VA_DCL
 
     if (errflag || noerrs) {
 	if (noerrs < 2)
-	    errflag = 1;
+	    errflag |= ERRFLAG_ERROR;
 	return;
     }
 
@@ -161,7 +161,7 @@ VA_DCL
     VA_GET_ARG(ap, fmt, const char *);
     zwarning(NULL, fmt, ap);
     va_end(ap);
-    errflag = 1;
+    errflag |= ERRFLAG_ERROR;
 }
 
 /**/
@@ -181,7 +181,7 @@ VA_DCL
     VA_GET_ARG(ap, fmt, const char *);
     zwarning(cmd, fmt, ap);
     va_end(ap);
-    errflag = 1;
+    errflag |= ERRFLAG_ERROR;
 }
 
 /**/
@@ -330,7 +330,7 @@ zerrmsg(FILE *file, const char *fmt, va_list ap)
 		num = va_arg(ap, int);
 		if (num == EINTR) {
 		    fputs("interrupt\n", file);
-		    errflag = 1;
+		    errflag |= ERRFLAG_ERROR;
 		    return;
 		}
 		errmsg = strerror(num);
diff --git a/Src/zsh.h b/Src/zsh.h
index 031deaf3f..b366e0ff4 100644
--- a/Src/zsh.h
+++ b/Src/zsh.h
@@ -2623,6 +2623,20 @@ enum trap_state {
 #define IN_EVAL_TRAP() \
     (intrap && !trapisfunc && traplocallevel == locallevel)
 
+/*
+ * Bits in the errflag variable.
+ */
+enum errflag_bits {
+    /*
+     * Standard internal error bit.
+     */
+    ERRFLAG_ERROR = 1,
+    /*
+     * User interrupt.
+     */
+    ERRFLAG_INT = 2
+};
+
 /***********/
 /* Sorting */
 /***********/