This repository reproduces a segfault with Node's ESM support.
System: Linux 5.0.8 64-bit
Node: 12.1.0
Install the dependencies with npm or yarn (lock files are provided) and execute the following command (or run.sh):
node --experimental-modules --es-module-specifier-resolution=node node_modules/mocha/bin/_mocha build/test/test.esm.js --delay --async --no-config --no-package --no-opts --diff --extension js --reporter spec --slow 75 --timeout 2000 --ui bdd
It has a very high probability of causing a segfault (all the time during my tests, read forward why this is not deterministic).
Here is a log of my console:
/data/projects/web/node-esm-sigsegv $ ./run.sh
+ node --experimental-modules --es-module-specifier-resolution=node node_modules/mocha/bin/_mocha build/test/test.esm.js --delay --async --no-config --no-package --no-opts --diff --extension js --reporter spec --slow 75 --timeout 2000 --ui bdd
(node:11259) ExperimentalWarning: The ESM module loader is experimental.
./run.sh: line 4: 11259 Segmentation fault (core dumped) node --experimental-modules --es-module-specifier-resolution=node node_modules/mocha/bin/_mocha build/test/test.esm.js --delay --async --no-config --no-package --no-opts --diff --extension js --reporter spec --slow 75 --timeout 2000 --ui bdd
/data/projects/web/node-esm-sigsegv $ ./run.sh
+ node --experimental-modules --es-module-specifier-resolution=node node_modules/mocha/bin/_mocha build/test/test.esm.js --delay --async --no-config --no-package --no-opts --diff --extension js --reporter spec --slow 75 --timeout 2000 --ui bdd
(node:11279) ExperimentalWarning: The ESM module loader is experimental.
./run.sh: line 4: 11279 Segmentation fault (core dumped) node --experimental-modules --es-module-specifier-resolution=node node_modules/mocha/bin/_mocha build/test/test.esm.js --delay --async --no-config --no-package --no-opts --diff --extension js --reporter spec --slow 75 --timeout 2000 --ui bdd
/data/projects/web/node-esm-sigsegv $ ./run.sh
+ node --experimental-modules --es-module-specifier-resolution=node node_modules/mocha/bin/_mocha build/test/test.esm.js --delay --async --no-config --no-package --no-opts --diff --extension js --reporter spec --slow 75 --timeout 2000 --ui bdd
(node:11300) ExperimentalWarning: The ESM module loader is experimental.
./run.sh: line 4: 11300 Segmentation fault (core dumped) node --experimental-modules --es-module-specifier-resolution=node node_modules/mocha/bin/_mocha build/test/test.esm.js --delay --async --no-config --no-package --no-opts --diff --extension js --reporter spec --slow 75 --timeout 2000 --ui bdd
/data/projects/web/node-esm-sigsegv $ ./run.sh
+ node --experimental-modules --es-module-specifier-resolution=node node_modules/mocha/bin/_mocha build/test/test.esm.js --delay --async --no-config --no-package --no-opts --diff --extension js --reporter spec --slow 75 --timeout 2000 --ui bdd
(node:11321) ExperimentalWarning: The ESM module loader is experimental.
./run.sh: line 4: 11321 Segmentation fault (core dumped) node --experimental-modules --es-module-specifier-resolution=node node_modules/mocha/bin/_mocha build/test/test.esm.js --delay --async --no-config --no-package --no-opts --diff --extension js --reporter spec --slow 75 --timeout 2000 --ui bdd
This command ultimately imports build/test/test.esm.js which in turn sequentially imports the .spec.mjs files from the test/test directory.
The more files are imported, the higher the chance of segfault.
If I comment out all the dynamic imports but one, the command seems to never crash:
(async () => {
await import("./test/types/white-list.spec.mjs");
run();
})();
If I use 2 or 3 dynamic imports, I get a segfault about 25% of the time. That's why I think that the behavior is non-deterministic.
If I use 4 or more dynamic imports, it always crashes.