[src/trunk]: src/usr.bin/make make(1): add note about "..." with duplicate sh...

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/43b9ae6be93e
branches:  trunk
changeset: 1014753:43b9ae6be93e
user:      rillig <rillig%NetBSD.org@localhost>
date:      Thu Oct 01 21:00:55 2020 +0000

description:
make(1): add note about "..." with duplicate shell commands

diffstat:

 usr.bin/make/compat.c |  9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diffs (30 lines):

diff -r c4484b515fbc -r 43b9ae6be93e usr.bin/make/compat.c
--- a/usr.bin/make/compat.c     Thu Oct 01 18:34:06 2020 +0000
+++ b/usr.bin/make/compat.c     Thu Oct 01 21:00:55 2020 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: compat.c,v 1.159 2020/09/28 23:13:57 rillig Exp $      */
+/*     $NetBSD: compat.c,v 1.160 2020/10/01 21:00:55 rillig Exp $      */
 
 /*
  * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
@@ -99,7 +99,7 @@
 #include    "pathnames.h"
 
 /*     "@(#)compat.c   8.2 (Berkeley) 3/19/94" */
-MAKE_RCSID("$NetBSD: compat.c,v 1.159 2020/09/28 23:13:57 rillig Exp $");
+MAKE_RCSID("$NetBSD: compat.c,v 1.160 2020/10/01 21:00:55 rillig Exp $");
 
 static GNode       *curTarg = NULL;
 static void CompatInterrupt(int);
@@ -207,6 +207,11 @@
     errCheck = !(gn->type & OP_IGNORE);
     doIt = FALSE;
 
+    /* Luckily the commands don't end up in a string pool, otherwise
+     * this comparison could match too early, in a dependency using "..."
+     * for delayed commands, run in parallel mode, using the same shell
+     * command line more than once; see JobPrintCommand.
+     * TODO: write a unit-test to protect against this potential bug. */
     cmdNode = Lst_FindDatum(gn->commands, cmd);
     (void)Var_Subst(cmd, gn, VARE_WANTRES, &cmdStart);
     /* TODO: handle errors */