[This enhancement request is for Gnu make 3.79.1.]
It would be a useful thing if Make variable names were forbidden to
contain slash (`/'), as well as `:', `#', and `='. The reason I make
this request is that I was rebuilding a Linux kernel in a directory
named (more or less) `/auto/LABEL=Backup/linux-2.4.20-24.8.test4'.
The Linux kernel makefile expands out the full path of the files it is
working with, rather than using relative names, so at one point, it
generated a Makefile rule looking something like this:
cciss.h: \
/auto/LABEL=Backup/linux-2.4.20-24.8.test4/include/linux/genhd.h \
/auto/LABEL=Backup/linux-2.4.20-24.8.test4/drivers/block/cciss_cmd.h
@touch cciss.h
Because the first non-whitespace thing after the `:' contained an `=',
Make interpreted it as a target-specific variable assignment, not a
rule. Due to the organization of the Linux kernel makefiles, it is
difficult to avoid this problem without moving the file tree to a
different place.
Following is a patch which should forbid `/' in variable names (in
most circumstances), and thus allow `=', `+=', and `?=' in path names
after the first `/'. This does not permit `:=' in path names, whose
interpretation is much more complex. But that problem is no worse
than before.
The patch includes a new test, variables/names_equal, to verify that
paths containing `=' can be used. The patched code passes all the
existing tests as well.
The patch adds comments to mark a couple of cases in switches that
fall through to the next case, which is good coding style.
In addition, the patch reorganizes a "case ':'" in read.c to allow
easy insertion of code to handle `:=' when someone feels up to writing
it. The new behavior is different than before -- previously, if a
device-letter is used on MS-DOS, the "case ':'" falls through to the
following "case '$'", which appears to be incorrect behavior, even
though it may produce the correct result in most cases. (E.g., it
looks like the path `C:$(variable)' will not be variable-substituted
correctly.)
The patch modifies the texinfo to specify that `/' is forbidden in
variable names, and why.
Dale
----------------------------------------------------------------------
diff -r --new-file -u --exclude='*~' --exclude=work make-3.79.1.orig/make.texinfo
make-3.79.1/make.texinfo
--- make-3.79.1.orig/make.texinfo 2000-06-20 10:00:17.000000000 -0400
+++ make-3.79.1/make.texinfo 2004-01-09 11:50:11.000000000 -0500
@@ -4000,11 +4000,13 @@
programs to run, directories to look in for source files, directories to
write output in, or anything else you can imagine.
-A variable name may be any sequence of characters not containing @samp{:},
[EMAIL PROTECTED], @samp{=}, or leading or trailing whitespace. However,
-variable names containing characters other than letters, numbers, and
-underscores should be avoided, as they may be given special meanings in the
-future, and with some shells they cannot be passed through the environment to a
+A variable name may be any sequence of characters not containing
[EMAIL PROTECTED]:}, @samp{#}, @samp{=}, @samp{/} or leading or trailing
+whitespace. (@samp{/} is forbidden so that path names containing
[EMAIL PROTECTED] can be handled.) However, variable names containing
+characters other than letters, numbers, and underscores should be
+avoided, as they may be given special meanings in the future, and with
+some shells they cannot be passed through the environment to a
[EMAIL PROTECTED]
(@pxref{Variables/Recursion, ,Communicating Variables to a [EMAIL PROTECTED]).
diff -r --new-file -u --exclude='*~' --exclude=work make-3.79.1.orig/read.c
make-3.79.1/read.c
--- make-3.79.1.orig/read.c 2000-06-21 15:33:30.000000000 -0400
+++ make-3.79.1/read.c 2004-01-09 13:00:25.000000000 -0500
@@ -2264,6 +2264,10 @@
enum make_word_type wtype = w_bogus;
char *p = buffer, *beg;
char c;
+ /* 1 if we have seen a character which cannot be part of a variable name,
+ and thus if we seen `=', it is part of the token, not a variable
+ definition. */
+ int non_variable_character_seen = 0;
/* Skip any leading whitespace. */
while (isblank ((unsigned char)*p))
@@ -2313,6 +2317,7 @@
wtype = w_varassign;
break;
}
+ /* Falls through to next case. */
default:
if (delim && strchr (delim, c))
@@ -2326,7 +2331,12 @@
/* This is some non-operator word. A word consists of the longest
string of characters that doesn't contain whitespace, one of [:=#],
- or [?+]=, or one of the chars in the DELIM string. */
+ or [?+]=, or one of the chars in the DELIM string.
+ In addition, `=' is permitted if the preceding characters contain
+ a character (currently, only `/' has this role) specifically excluded from
+ variable names.
+ In addition, on MS-DOS/MS-Windows systems, `:' is permitted in certain
+ circumstances as a drive specifier. */
/* We start out assuming a static word; if we see a variable we'll
adjust our assumptions then. */
@@ -2343,19 +2353,28 @@
case '\0':
case ' ':
case '\t':
- case '=':
case '#':
goto done_word;
case ':':
+ /* A word can include a colon under certain circumstances. The
+ following clauses specify when it can. */
+ if (0
#if defined(__MSDOS__) || defined(WINDOWS32)
- /* A word CAN include a colon in its drive spec. The drive
- spec is allowed either at the beginning of a word, or as part
- of the archive member name, like in "libfoo.a(d:/foo/bar.o)". */
- if (!(p - beg >= 2
- && (*p == '/' || *p == '\\') && isalpha ((unsigned char)p[-2])
- && (p - beg == 2 || p[-3] == '(')))
+ /* A word can include a colon in its drive spec. The drive
+ spec is allowed either at the beginning of a word, or as part
+ of the archive member name, like in
+ "libfoo.a(d:/foo/bar.o)". */
+ || (p - beg >= 2
+ && (*p == '/' || *p == '\\') && isalpha ((unsigned char)p[-2])
+ && (p - beg == 2 || p[-3] == '('))
#endif
+ )
+ /* If any clause is true, continue reading characters of the
+ word. */
+ break;
+ /* If no clause is true, this `:' is a special character and should
+ not be included in the word. */
goto done_word;
case '$':
@@ -2389,7 +2408,7 @@
case '?':
case '+':
- if (*p == '=')
+ if (!non_variable_character_seen && *p == '=')
goto done_word;
break;
@@ -2405,7 +2424,17 @@
}
break;
+ case '=':
+ if (!non_variable_character_seen)
+ goto done_word;
+ /* Fall through to next case. */
+
default:
+ /* Currently, `/' is the only character specifically excluded from
+ variable names (that does not have additional syntax that is
+ already handled). */
+ if (c == '/')
+ non_variable_character_seen = 1;
if (delim && strchr (delim, c))
goto done_word;
break;
diff -r --new-file -u --exclude='*~' --exclude=work
make-3.79.1.orig/tests/scripts/variables/names_equal
make-3.79.1/tests/scripts/variables/names_equal
--- make-3.79.1.orig/tests/scripts/variables/names_equal 1969-12-31
19:00:00.000000000 -0500
+++ make-3.79.1/tests/scripts/variables/names_equal 2004-01-09 12:47:46.000000000
-0500
@@ -0,0 +1,48 @@
+# -*-perl-*-
+
+$description = "Test that variable names may not contain `/', specifically in
target-specific variable definitions.";
+
+$details = "";
+
+open(MAKEFILE, "> $makefile");
+
+# The Contents of the MAKEFILE ...
+
+# Prepare a makefile with rules that contain the variable assignment
+# operators `=', `+=' and `?=' within paths.
+# Note that `:=' is NOT allowed, since that case involves the messy semantics
+# of `:', which is a problem that is not addressed in this test.
+
+print MAKEFILE <<'EOF';
+all : target1 target2 target3
+
+target1 : ./=a
+ @echo processing target1
+
+./=a :
+ @echo processing ./=a
+
+target2 : ./+=a
+ @echo processing target2
+
+./+=a :
+ @echo processing ./+=a
+
+target3 : ./?=a
+ @echo processing target3
+
+./?=a :
+ @echo processing ./?=a
+EOF
+
+# END of Contents of MAKEFILE
+
+close(MAKEFILE);
+
+# TEST #1
+# -------
+
+&run_make_with_options($makefile, "", &get_logfile);
+$answer = "processing ./=a\nprocessing target1\nprocessing ./+=a\nprocessing
target2\nprocessing ./?=a\nprocessing target3\n";
+&compare_output($answer, &get_logfile(1));
+1;
diff -r --new-file -u --exclude='*~' --exclude=work make-3.79.1.orig/variable.c
make-3.79.1/variable.c
--- make-3.79.1.orig/variable.c 2000-05-19 12:36:08.000000000 -0400
+++ make-3.79.1/variable.c 2004-01-09 12:18:34.000000000 -0500
@@ -798,7 +798,9 @@
while (1)
{
c = *p++;
- if (c == '\0' || c == '#')
+ /* `/' is now forbidden in variable names so that paths containing `='
+ (at least, after the first `/') can be processed. */
+ if (c == '\0' || c == '#' || c == '/')
return 0;
if (c == '=')
{
----------------------------------------------------------------------
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