 @@ -1,14 +1,14 @@
-/*	$NetBSD: var.c,v 1.457 2020/08/22 19:30:58 sjg Exp $	*/
+/*	$NetBSD: var.c,v 1.458 2020/08/22 20:31:50 rillig Exp $	*/
 /*
  * Copyright (c) 1988, 1989, 1990, 1993
  *	The Regents of the University of California.  All rights reserved.
+ *
  * This code is derived from software contributed to Berkeley by
  * Adam de Boor.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
 @@ -59,34 +59,34 @@
  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
 #ifndef MAKE_NATIVE
-static char rcsid[] = "$NetBSD: var.c,v 1.457 2020/08/22 19:30:58 sjg Exp $";
+static char rcsid[] = "$NetBSD: var.c,v 1.458 2020/08/22 20:31:50 rillig Exp $";
 #else
 #include <sys/cdefs.h>
 #ifndef lint
 #if 0
 static char sccsid[] = "@(#)var.c	8.3 (Berkeley) 3/19/94";
 #else
-__RCSID("$NetBSD: var.c,v 1.457 2020/08/22 19:30:58 sjg Exp $");
+__RCSID("$NetBSD: var.c,v 1.458 2020/08/22 20:31:50 rillig Exp $");
 #endif
 #endif /* not lint */
 #endif
 /*-
  * var.c --
  *	Variable-handling functions
+ *
  * Interface:
  *	Var_Set		    Set the value of a variable in the given
  *			    context. The variable is created if it doesn't
  *			    yet exist.
+ *
 @@ -768,44 +768,44 @@ Var_UnExport(const char *str)
 	free(av);
 	if (varnames != str) {
 	    Var_Delete(MAKE_EXPORTED, VAR_GLOBAL);
 	    free(varnames_freeIt);
+	}
+    }
+}
 /* See Var_Set for documentation. */
 void
 Var_Set_with_flags(const char *name, const char *val, GNode *ctxt,
 		   VarSet_Flags flags)
+{
     const char *unexpanded_name = name;
     char *name_freeIt = NULL;
     Var *v;
     /*
      * We only look for a variable in the given context since anything set
      * here will override anything in a lower context, so there's not much
      * point in searching them all just to save a bit of memory...
      */
-    if (strchr(name, '$') != NULL) {
+    if (strchr(name, '$') != NULL)
 	const char *unexpanded_name = name;
 	name = name_freeIt = Var_Subst(name, ctxt, VARE_WANTRES);
 	if (name[0] == '\0') {
-	    VAR_DEBUG("Var_Set(\"%s\", \"%s\", ...) "
+    if (name[0] == '\0') {
-		      "name expands to empty string - ignored\n",
+	VAR_DEBUG("Var_Set(\"%s\", \"%s\", ...) "
-		      unexpanded_name, val);
+		  "name expands to empty string - ignored\n",
-	    free(name_freeIt);
+		  unexpanded_name, val);
-	    return;
+	free(name_freeIt);
 	return;
+    }
     if (ctxt == VAR_GLOBAL) {
 	v = VarFind(name, VAR_CMD, 0);
 	if (v != NULL) {
 	    if (v->flags & VAR_FROM_CMD) {
 		VAR_DEBUG("%s:%s = %s ignored!\n", ctxt->name, name, val);
 		goto out;
+	    }
 	    VarFreeEnv(v, TRUE);
+	}
+    }

 @@ -1,21 +1,22 @@
-# $NetBSD: varname-empty.mk,v 1.1 2020/08/22 20:23:14 rillig Exp $
+# $NetBSD: varname-empty.mk,v 1.2 2020/08/22 20:31:50 rillig Exp $
+#
 # Tests for the special variable with the empty name.
+#
 # The variable "" is not supposed to be assigned any value.
 # This is because it is heavily used in the .for loop expansion,
 # as well as to generate arbitrary strings, as in ${:Ufallback}.
-# Oops.
+# Until 2020-08-22 it was possible to assign a value to the variable with
 # the empty name, leading to all kinds of unexpected effects.
 !=	echo 'value'
 # The .for loop expands the expression ${i} to ${:U1}, ${:U2} and so on.
 # This only works if the variable with the empty name is guaranteed to
 # be undefined.
 .for i in 1 2 3
 NUMBERS+=	${i}
 .endfor
 all:
 	@echo ${:Ufallback}
 	@echo ${NUMBERS}

 @@ -1,3 +1,3 @@
-value
+fallback
-value value value
+2 3
 exit status 0