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make(1): in lint mode, complain about erroneous $$

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Since 2008-12-21, make has silently ignored strange variable names in
constructs like '$$', '$}', '$' followed by nothing.  Ignoring these
bugs in makefiles instead of reporting them is not a good idea.

To improve the situation, make complains about these errors now, but
only in lint mode (-dL).  This preserves existing behavior while still
allowing to validate existing makefiles that they don't depend on this
bug.

If the test phase goes well, these error messages may be enabled
unconditionally.

https://mail-index.netbsd.org/pkgsrc-users/2020/09/12/msg032229.html
This commit is contained in:
rillig 2020-09-13 07:42:20 +00:00
parent 207ba25b58
commit 173d4ecff3
3 changed files with 79 additions and 11 deletions
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7
usr.bin/make/unit-tests/varmod.exp
View File

@ -1 +1,6 @@
exit status 0
make: "varmod.mk" line 42: To escape a dollar, use \$, not $$, at "$$:L} != """
make: "varmod.mk" line 42: Invalid variable name ':', at "$:L} != """
make: "varmod.mk" line 47: Dollar followed by nothing
make: Fatal errors encountered -- cannot continue
make: stopped in unit-tests
exit status 1

51
usr.bin/make/unit-tests/varmod.mk
View File

@ -1,8 +1,51 @@
# $NetBSD: varmod.mk,v 1.2 2020/08/16 14:25:16 rillig Exp $
# $NetBSD: varmod.mk,v 1.3 2020/09/13 07:42:20 rillig Exp $
#
# Tests for variable modifiers, such as :Q, :S,from,to or :Ufallback.
# TODO: Implementation
DOLLAR1= $$
DOLLAR2= ${:U\$}
all:
@:;
# To get a single '$' sign in the value of a variable expression, it has to
# be written as '$$' in a literal variable value.
#
# See Var_Parse, where it calls Var_Subst.
.if ${DOLLAR1} != "\$"
. error
.endif
# Another way to get a single '$' sign is to use the :U modifier. In the
# argument of that modifier, a '$' is escaped using the backslash instead.
#
# See Var_Parse, where it calls Var_Subst.
.if ${DOLLAR2} != "\$"
. error
.endif
# It is also possible to use the :U modifier directly in the expression.
#
# See Var_Parse, where it calls Var_Subst.
.if ${:U\$} != "\$"
. error
.endif
# XXX: As of 2020-09-13, it is not possible to use '$$' in a variable name
# to mean a single '$'. This contradicts the manual page, which says that
# '$' can be escaped as '$$'.
.if ${$$:L} != ""
. error
.endif
# In lint mode, make prints helpful error messages.
# For compatibility, make does not print these error messages in normal mode.
# Should it?
.MAKEFLAGS: -dL
.if ${$$:L} != ""
. error
.endif
# A '$' followed by nothing is an error as well.
.if ${:Uword:@word@${word}$@} != "word"
. error
.endif
all: # nothing

32
usr.bin/make/var.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: var.c,v 1.506 2020/09/13 05:55:39 rillig Exp $ */
/* $NetBSD: var.c,v 1.507 2020/09/13 07:42:20 rillig Exp $ */
/*
* Copyright (c) 1988, 1989, 1990, 1993
@ -69,14 +69,14 @@
*/
#ifndef MAKE_NATIVE
static char rcsid[] = "$NetBSD: var.c,v 1.506 2020/09/13 05:55:39 rillig Exp $";
static char rcsid[] = "$NetBSD: var.c,v 1.507 2020/09/13 07:42:20 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 1.506 2020/09/13 05:55:39 rillig Exp $");
__RCSID("$NetBSD: var.c,v 1.507 2020/09/13 07:42:20 rillig Exp $");
#endif
#endif /* not lint */
#endif
@ -3369,6 +3369,27 @@ ParseVarname(const char **pp, char startc, char endc,
return Buf_Destroy(&buf, FALSE);
}
static Boolean
ValidShortVarname(char varname, const char *start)
{
if (varname != '\0' && strchr(")}:$", varname) == NULL)
return TRUE;
if (!DEBUG(LINT))
return FALSE;
if (varname == '$')
Parse_Error(PARSE_FATAL,
"To escape a dollar, use \\$, not $$, at \"%s\"", start);
else if (varname == '\0')
Parse_Error(PARSE_FATAL, "Dollar followed by nothing");
else
Parse_Error(PARSE_FATAL,
"Invalid variable name '%c', at \"%s\"", varname, start);
return FALSE;
}
/*-
*-----------------------------------------------------------------------
* Var_Parse --
@ -3454,8 +3475,7 @@ Var_Parse(const char **pp, GNode *ctxt, VarEvalFlags eflags, void **freePtr)
* value if it exists.
*/
/* Error out some really stupid names */
if (startc == '\0' || strchr(")}:$", startc)) {
if (!ValidShortVarname(startc, start)) {
(*pp)++;
return var_Error;
}
@ -3572,7 +3592,7 @@ Var_Parse(const char **pp, GNode *ctxt, VarEvalFlags eflags, void **freePtr)
* return.
*/
nstr = Buf_GetAll(&v->val, NULL);
if (strchr(nstr, '$') != NULL && (eflags & VARE_WANTRES) != 0) {
if (strchr(nstr, '$') != NULL && (eflags & VARE_WANTRES)) {
nstr = Var_Subst(nstr, ctxt, eflags);
*freePtr = nstr;
}