Generated Makefile `trap 'kill 0'` kills the parent process group under `make -n` — VS Code (Makefile Tools) crashes on folder open

[ksenthil86]

Summary

The generated Makefile's start target uses trap 'kill 0' EXIT:

https://github.com/neo4j-labs/create-context-graph/blob/main/src/create_context_graph/templates/base/Makefile.j2#L10-L15

start:
	@echo "Starting {{ domain.name }} Context Graph..."
	@trap 'kill 0' EXIT; \
		$(MAKE) dev-backend & \
		$(MAKE) dev-frontend & \
		wait

Because the recipe line contains $(MAKE), GNU make executes it even under --dry-run/-n (this is documented MAKE-variable special handling: recipe lines containing $(MAKE) are always run, -n is only propagated to the sub-makes). Under -n the sub-makes print and exit immediately, wait returns, the shell exits — and the EXIT trap fires kill 0, which SIGTERMs the entire process group of whatever invoked make.

Impact: opening a generated project in VS Code kills VS Code

VS Code's popular Makefile Tools extension (ms-vscode.makefile-tools) auto-runs make --dry-run on the default target when a folder containing a Makefile is opened ("configure on open"). start is the first target, so it is the default. The extension host spawns make inside VS Code's process group, so ~3 seconds after opening any project generated by create-context-graph, kill 0 SIGTERMs every VS Code process — all windows, the extension host, pty host, everything — at once.

From the user's perspective, VS Code hard-crashes every time they open the generated project, with no error pointing at the Makefile. We spent a while chasing antivirus/system-level red herrings before tracing the SIGTERM wave (signal 15 to the whole process family, exactly at Makefile Tools activation) back to this trap.

Anything else that runs make -n (shell completion helpers, other IDE integrations, CI dry-runs) is similarly killed.

Reproduction

In any generated project (macOS, GNU make 3.81 and 4.x):

$ make -n start; echo "exit: $?"
# → the process group receives SIGTERM; in an interactive shell your terminal tab dies.

Isolated repro showing the signal:

$ python3 -c "
import os, subprocess
p = subprocess.Popen(['make','-n','start'], preexec_fn=os.setsid)
print('returncode:', p.wait())"
returncode: -15

Or simply: open the generated folder in VS Code with the Makefile Tools extension installed → the whole VS Code app is killed within seconds, reproducibly.

Suggested fix

Kill only the jobs the recipe started, not the whole process group:

start:
	@echo "Starting {{ domain.name }} Context Graph..."
	@trap 'kill $$(jobs -p) 2>/dev/null' EXIT; \
		$(MAKE) dev-backend & \
		$(MAKE) dev-frontend & \
		wait

This preserves the intended behavior (Ctrl-C / exit tears down both dev servers) and is inert under make -n, since jobs -p only lists the recipe's own background children. Verified: make -n start returns 0 with this change, and VS Code opens the project normally.

🤖 Filed with the help of Claude Code after debugging this on a generated project.