Throwing an exception from a finalizer can cause the following fatal
error:
Error: async hook stack has become corrupted (actual: 2, expected: 0)
1: 0x970b5a node::InternalCallbackScope::~InternalCallbackScope()
[./node]
2: 0x99dda0 node::Environment::RunTimers(uv_timer_s*) [./node]
3: 0x13d8b22 [./node]
4: 0x13dbe42 uv_run [./node]
5: 0xa57974 node::NodeMainInstance::Run() [./node]
6: 0x9dbc17 node::Start(int, char**) [./node]
7: 0x7f4965417f43 __libc_start_main [/lib64/libc.so.6]
8: 0x96f4ae _start [./node]
By https://github.com/nodejs/node/issues/34341#issuecomment-658426281,
calling into JS from a finalizer and/or throwing exceptions from there
is not advised, because the stack may or may not be set up for JS
execution. The best solution is to run the user's finalizer from a
`SetImmediate()` callback.
Signed-off-by: Gabriel Schulhof <gabriel.schulhof@intel.com>
Fixes: https://github.com/nodejs/node/issues/34341
PR-URL: https://github.com/nodejs/node/pull/34386
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>
Since worker threads are complete Node.js environments, including the
ability to load native addons, and since those native addons can
allocate resources to be freed when objects go out of scope, and since,
upon worker thread exit, the engine does not invoke the weak callbacks
responsible for freeing resources which still have references, this
modification introduces tracking for weak references such that a list
of outstanding weak references is maintained. This list is traversed
during environment teardown. The callbacks for the remaining weak
references are called.
This change is also relevant for Node.js embedder scenarios, because in
those cases the process also outlives the `node::Environment` and
therefore weak callbacks should also be rendered as environment cleanup
hooks to ensure proper cleanup after native addons. This changes
introduces the means by which this can be accomplished.
A benchmark is included which measures the time it takes to execute the
weak reference callback for a given number of weak references.
Re: https://github.com/tc39/proposal-weakrefs/issues/125#issuecomment-535832130
PR-URL: https://github.com/nodejs/node/pull/28428
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
