URL:
<https://savannah.gnu.org/bugs/?63016>
Summary: Recursive variable references itself (eventually)
when exporting to $(shell)
Project: make
Submitter: mdorey
Submitted: Sun 04 Sep 2022 04:28:29 PM PDT
Severity: 3 - Normal
Item Group: Bug
Status: None
Privacy: Public
Assigned to: None
Open/Closed: Open
Discussion Lock: Any
Component Version: SCM
Operating System: POSIX-Based
Fixed Release: None
Triage Status: None
_______________________________________________________
Follow-up Comments:
-------------------------------------------------------
Date: Sun 04 Sep 2022 04:28:29 PM PDT By: Martin Dorey <mdorey>
With this Makefile:
martind@sirius:~/tmp/make-2022-09-04$ cat Makefile
A = $(shell :)
export B = $(A)
default:; $(A)
martind@sirius:~/tmp/make-2022-09-04$
... which bears a certain resemblance to the "export HI" example added to
make.texi in:
https://git.savannah.gnu.org/cgit/make.git/commit/?id=98da874c43035a490cdca81331724f233a3d0c9a
... under:
[SV 10593] Export variables to $(shell ...) commands
And yesterday's code from git:
martind@sirius:~/tmp/make-2022-09-04$ make --version
GNU Make 4.3.90
Built for x86_64-pc-linux-gnu
Copyright (C) 1988-2022 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later
<https://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
martind@sirius:~/tmp/make-2022-09-04$
I get the following error:
martind@sirius:~/tmp/make-2022-09-04$ make
Makefile:1: *** Recursive variable 'A' references itself (eventually). Stop.
martind@sirius:~/tmp/make-2022-09-04$
... where make-4.3 just says:
martind@platinum:~/tmp/make-2022-09-04$ /usr/bin/make
make: 'default' is up to date.
martind@platinum:~/tmp/make-2022-09-04$
The fatal error happens from the following stack:
(gdb) bt
#0 recursively_expand_for_file (v=v@entry=0x5616496613c0,
file=file@entry=0x0) at src/expand.c:124
#1 0x0000561647495aa2 in reference_variable (length=1, name=0x561649665cd2
"A)", o=0x561649665c00 "")
at src/expand.c:177
#2 variable_expand_string (line=<optimized out>, line@entry=0x0,
string=<optimized out>,
length=length@entry=18446744073709551615) at src/expand.c:383
#3 0x0000561647495d90 in variable_expand (line=<optimized out>) at
src/expand.c:420
#4 variable_expand_for_file (file=0x0, line=<optimized out>) at
src/expand.c:467
#5 allocated_variable_expand_for_file (file=0x0, line=<optimized out>) at
src/expand.c:569
#6 recursively_expand_for_file (v=v@entry=0x561649661440,
file=file@entry=0x0) at src/expand.c:143
#7 0x00005616474b13b1 in target_environment (file=file@entry=0x0,
recursive=recursive@entry=0) at src/variable.c:1114
#8 0x000056164749b7d2 in func_shell_base (o=0x5616496656e0 "",
argv=<optimized out>, trim_newlines=1)
at src/function.c:1879
#9 0x000056164749bcff in handle_function (op=op@entry=0x7ffe9895f2b8,
stringp=stringp@entry=0x7ffe9895f2b0)
at src/function.c:2669
#10 0x00005616474954d7 in variable_expand_string (line=<optimized out>,
line@entry=0x0, string=<optimized out>,
length=length@entry=18446744073709551615) at src/expand.c:261
#11 0x0000561647495d90 in variable_expand (line=<optimized out>) at
src/expand.c:420
#12 variable_expand_for_file (file=0x0, line=<optimized out>) at
src/expand.c:467
#13 allocated_variable_expand_for_file (file=0x0, line=<optimized out>) at
src/expand.c:569
#14 recursively_expand_for_file (v=v@entry=0x5616496613c0,
file=file@entry=0x0) at src/expand.c:143
#15 0x0000561647495aa2 in reference_variable (length=1, name=0x5616496656c3
"A)",
o=0x5616496655f1 "\333\353%\267\177") at src/expand.c:177
#16 variable_expand_string (line=<optimized out>, line@entry=0x0,
string=<optimized out>,
length=length@entry=18446744073709551615) at src/expand.c:383
#17 0x0000561647495edb in variable_expand (line=<optimized out>) at
src/expand.c:420
#18 variable_expand_for_file (line=<optimized out>, file=<optimized out>) at
src/expand.c:478
#19 0x0000561647495f44 in allocated_variable_expand_for_file (line=<optimized
out>, file=file@entry=0x5616496614a0)
at src/expand.c:569
#20 0x00005616474a1f11 in new_job (file=0x5616496614a0) at src/job.c:1825
#21 0x00005616474adc40 in remake_file (file=0x5616496614a0) at
src/remake.c:1258
#22 update_file_1 (depth=<optimized out>, file=<optimized out>) at
src/remake.c:856
#23 update_file (file=file@entry=0x5616496614a0, depth=<optimized out>) at
src/remake.c:343
#24 0x00005616474adeb8 in update_goal_chain (goaldeps=<optimized out>) at
src/remake.c:160
#25 0x0000561647491283 in main (argc=<optimized out>, argv=<optimized out>,
envp=<optimized out>) at src/main.c:2860
(gdb)
Comparison with similar lines in the surrounding source suggests there's a
missing newline on the end of the warning that I think I was hoped to get in
this situation:
+ DB (DB_VERBOSE, (_("%s:%lu: Skipping export of %s to shell
function due to recursive expansion"),
+ v->fileinfo.filenm, v->fileinfo.lineno,
v->name));
I didn't bother generating a minimal example for it but I've seen the message
run into the next piece of debugging output.
I'm not sure I'm really suggesting this hack:
martind@sirius:~/download/make$ git diff | cat
diff --git a/src/expand.c b/src/expand.c
index 6bc2ac59..ee0a45f5 100644
--- a/src/expand.c
+++ b/src/expand.c
@@ -19,6 +19,7 @@ this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <assert.h>
#include "filedef.h"
+#include "debug.h"
#include "job.h"
#include "commands.h"
#include "variable.h"
@@ -120,10 +121,18 @@ recursively_expand_for_file (struct variable *v, struct
file *file)
if (v->expanding)
{
if (!v->exp_count)
- /* Expanding V causes infinite recursion. Lose. */
- OS (fatal, *expanding_var,
- _("Recursive variable '%s' references itself (eventually)"),
- v->name);
+ {
+ if (file == NULL)
+ {
+ DB (DB_VERBOSE, (_("%s:%lu: Skipping export of %s to shell
function due to recursive expansion\n"),
+ v->fileinfo.filenm, v->fileinfo.lineno,
v->name));
+ return strdup("skipped export to shell function due to
recursive expansion");
+ }
+ /* Expanding V causes infinite recursion. Lose. */
+ OS (fatal, *expanding_var,
+ _("Recursive variable '%s' references itself (eventually)"),
+ v->name);
+ }
--v->exp_count;
}
diff --git a/src/variable.c b/src/variable.c
index 30f4424a..26aed5db 100644
--- a/src/variable.c
+++ b/src/variable.c
@@ -19,7 +19,6 @@ this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <assert.h>
#include "filedef.h"
-#include "debug.h"
#include "dep.h"
#include "job.h"
#include "commands.h"
@@ -1102,15 +1101,6 @@ target_environment (struct file *file, int recursive)
go back into the environment unchanged. */
if (v->recursive && v->origin != o_env && v->origin !=
o_env_override)
{
- /* If V is being recursively expanded and this is for a shell
- function, just skip it. */
- if (v->expanding && file == NULL)
- {
- DB (DB_VERBOSE, (_("%s:%lu: Skipping export of %s to shell
function due to recursive expansion"),
- v->fileinfo.filenm, v->fileinfo.lineno,
v->name));
- continue;
- }
-
value = cp = recursively_expand_for_file (v, file);
}
martind@sirius:~/download/make$
... but it does fix this test case and doesn't regress make check, which was
already failing one test in functions/wildcard for me.
The $(shell) invocation which is provoking this for real was committed in 2004
as an alleged work around for:
[SV 443] $(wildcard) function uses directory cache: gives incorrect results
sometimes
I wish I could find the full story of that bug, because what little Savannah
has makes it look like it came from the same part of the same source base as
I'm now contemplating returning to $(wildcard) to avoid this, on the
prematurely pessimistic assumption that Paul won't want to fix this. If
anyone has the original correspondence, I'd be grateful. It's not in
https://lists.gnu.org/archive/html/bug-make/2002-05/index.html.
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