Segmentation Fault on Exported Resursively Expanded Variable

[MIAOW Miao]

Hi,

I found name of exported resursively expanded variable with $(shell ...) cannot be too long in gnu make version >= 4.4, otherwise a segmentation fault is triggled. 

I'm not sure if variable-name-too-long is a bug. However, make is supposed to tell me what's going wrong.

Here is a Makefile that can reproduce the segmentation fault:

THIS_LONG_VARIABLE_NAME_PREDUCE_THE_ERROR= $(shell echo hello)

export THIS_LONG_VARIABLE_NAME_PREDUCE_THE_ERROR

all: ; echo "abc"

Commands log:

user@fedora:~$ make

echo "abc"

Segmentation fault (core dumped)

user@fedora:~$ make --version

GNU Make 4.4.1

Built for x86_64-redhat-linux-gnu

...

user@fedora:~$ make --help

...

This program built for x86_64-redhat-linux-gnu

Report bugs to <bug-make@gnu.org>

The error can be reproduced on fedora 39 with the following 2 official builds of make by fedora project:

• make-4.4-1.fc38: https://kojipkgs.fedoraproject.org//packages/make/4.4/1.fc38/x86_64/make-4.4-1.fc38.x86_64.rpm
• make-4.4.1-2.fc39: https://kojipkgs.fedoraproject.org//packages/make/4.4.1/2.fc39/x86_64/make-4.4.1-2.fc39.x86_64.rpm

There is NO error with gnu make 4.3, tested both on Ubuntu 23.04 (make 4.3-4.1build1) and fedora39 (make-4.3-1.fc33):

• make 4.3-4.1build1: http://mirrors.kernel.org/ubuntu/pool/main/m/make-dfsg/make_4.3-4.1build1_amd64.deb
• make-4.3-1.fc33: https://kojipkgs.fedoraproject.org//packages/make/4.3/1.fc33/x86_64/make-4.3-1.fc33.x86_64.rpm

I think it may be caused by the new feature "shell-export". As is the "NEWS" file of Version 4.4 (31 Oct 2022):

* WARNING: Backward-incompatibility!

  Previously makefile variables marked as export were not exported to command

  started by the $(shell ...) function.  Now, all exported variables are

  exported to $(shell ...).  If this leads to recursion during expansion, the

  for backward-compatibility the value from the original environment is used.

  To detect this change search for 'shell-export' in the .FEATURES variable.

Best regards,

Yiren Guo

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