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process: improve stack trace on async(libuv) error

Rodrigo Muino Tomonari requested to merge github/fork/yorkie/process/improve-stack-trace into master
Checklist
  • make -j4 test (UNIX), or vcbuild test nosign (Windows) passes
  • tests and/or benchmarks are included
  • documentation is changed or added
  • commit message follows commit guidelines
Affected core subsystem(s)

process

Description of change

This patch saves the stack into TickObject by calling Error.captureStackTrace(), and will append those stacks if something went wrong.

For example:

require('child_process').spawn('error factory');

will throw:

Error: spawn error factory ENOENT
    at exports._errnoException (util.js:1026:11)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:182:32)
    at onErrorNT (internal/child_process.js:348:16)
    at _combinedTickCallback (internal/process/next_tick.js:74:11)
    at process._tickCallback (internal/process/next_tick.js:98:9)

but with this change, we will see the following:

internal/process/next_tick.js:102
          throw err;
          ^

Error: spawn error factory ENOENT
    at exports._errnoException (util.js:1026:11)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:193:32)
    at onErrorNT (internal/child_process.js:359:16)
    at _combinedTickCallback (internal/process/next_tick.js:74:11)
    at process._tickCallback (internal/process/next_tick.js:99:11)
    at Module.runMain (module.js:592:11)
    at run (bootstrap_node.js:382:7)
    at startup (bootstrap_node.js:137:9)
    at bootstrap_node.js:497:3
    at process.nextTick (internal/process/next_tick.js:160:24)
    at ChildProcess.spawn (internal/child_process.js:296:13)
    at Object.exports.spawn (child_process.js:385:9)
    at Object.<anonymous> (/Users/yorkieliu/workspace/test-process-next-tick.js:2:26)
    .......<more stack>

This would help developer to track what happened when some async callbacks are thrown, mostly are syscall error.

But to be noted that, this adds a possible unneeded .stack field to every TickObject and catch every call to callback. Both are hurting the perf in huge I guess. I'm not sure if we could land this, but I think the feature really saves time when debugging Node.js programs, perhaps an (CLI/API) option from user-land could be the way to go

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