How can I trap errors and interrupts in GNU make?

Question

I'm wondering if there's a way to implement trap in GNU make, similar to that built into BASH?

If the user presses CTRL-C, or if make itself fails (non-zero exit), I'd like to call a particular target or macro.

Answer 1

At this point in time, GNU make doesn't have native support.

There is a reliable workaround however:

.PHONY: internal-target external-target

external-target:
  bash -c "trap 'trap - SIGINT SIGTERM ERR; <DO CLEANUP HERE>; exit 1' SIGINT SIGTERM ERR; $(MAKE) internal-target"

internal-target:
  echo "doing stuff here"

This catches interruptions, terminations AND any non-zero exit codes.

Note the $(MAKE) so cmdline overrides and make options get passed to submake.

On trap:

• clear trap handler (with -)
• do the cleanup
• exit with non-zero exit status, so build automation tools report the failed build.

DELETE_ON_ERROR does NOT work for directories, so this is key for cleaning up after mktemp -d, for example

Replace <DO CLEANUP HERE> with valid CMD.

Answer 2

A simplified version of @kevinf’s answer which seems good enough for basic cases:

run:
    bash -c "trap 'docker-compose down' EXIT; docker-compose up --build"

(This example is for a reason: docker-compose up does say

When the command exits, all containers are stopped.

but it does not rm the stopped containers like docker run --rm would, so you can still see them with docker ps -a.)

Answer 3

No. GNU make’s signal handling already leaves a lot to be desired. From within its signal handler, it calls functions like printf that are not safe to be called from within a signal handler. I have seen this cause problems, for example .DELETE_ON_ERROR rules don’t always run if stderr is redirected to stdout.

For example, on a CentOS 7.4 box:

1. Create the following Makefile:

   .DELETE_ON_ERROR:
   
   foo:
           touch $@
           sleep 10
   

2. Open it in vim and run :make,

3. While it is sleeping, hit Ctrl-C

Vim/make prints

Press ENTER or type command to continue
touch foo
sleep 10
^C
shell returned 130

Interrupt: Press ENTER or type command to continue

Make was sent an interrupt signal, but foo still exists.