Error: ENOENT from File task

[BurtHarris]

I'm really just getting started with jake, but seem to be running into a wall repeatedly. I'm wondering if this is a windows-specific bug. I see similar error mentioned in issue #151, which also seems to be using Windows-style C:\... paths.

Am I doing something wrong? My jakefile:

const process = require('process')

const jarFile = `./tool/target/antlr4-typescript-4.6-SNAPSHOT-complete.jar`

const toolSources = new jake.FileList()
    .include(`tool/**`)
    .exclude(`tool/target/**`);

file(jarFile, toolSources, function () {
    console.log("building jar");
    process.chdir('tool')
    jake.exec(['npm i'])
})

task('default', [jarFile])

When the jarFile doesn't exist, then jake aborts...

C:\code\antlr4ts>jake --trace
building jar
jake aborted.
Error: ENOENT: no such file or directory, stat 'C:\code\antlr4ts\tool\tool\target\antlr4-typescript-4.6-SNAPSHOT-complete.jar'
    at Object.fs.statSync (fs.js:968:11)
    at FileTask.FileBase.updateModTime (C:\Users\Burt_\AppData\Roaming\nvm\v7.10.0\node_modules\jake\lib\task\file_task.js:82:20)
    at FileTask.FileBase.complete (C:\Users\Burt_\AppData\Roaming\nvm\v7.10.0\node_modules\jake\lib\task\file_task.js:89:12)
    at FileTask.TaskBase.run (C:\Users\Burt_\AppData\Roaming\nvm\v7.10.0\node_modules\jake\lib\task\task.js:290:12)
    at FileTask.TaskBase.runPrereqs (C:\Users\Burt_\AppData\Roaming\nvm\v7.10.0\node_modules\jake\lib\task\task.js:174:12)
    at FileTask.TaskBase.invoke (C:\Users\Burt_\AppData\Roaming\nvm\v7.10.0\node_modules\jake\lib\task\task.js:110:10)
    at TaskBase.nextPrereq (C:\Users\Burt_\AppData\Roaming\nvm\v7.10.0\node_modules\jake\lib\task\task.js:208:26)
    at TaskBase.runPrereqs (C:\Users\Burt_\AppData\Roaming\nvm\v7.10.0\node_modules\jake\lib\task\task.js:170:14)
    at TaskBase.invoke (C:\Users\Burt_\AppData\Roaming\nvm\v7.10.0\node_modules\jake\lib\task\task.js:110:10)
    at TaskBase.nextPrereq (C:\Users\Burt_\AppData\Roaming\nvm\v7.10.0\node_modules\jake\lib\task\task.js:208:26)

[BurtHarris]

Timing bug. If I single step through it, it seems to work. Seems like Jake may think the child process is complete before it really is.

[mde]

From a quick glance at your Jakefile, it looks like it is likely an async problem. The jake.exec in involves an async child-process operation, and you aren't waiting for it to get finished. The docs (http://jakejs.com/) have a lot of examples of how to use either async tasks, or evented tasks.

[mde]

Also worth noting that jake.exec was implemented circa Node version 0.3 because callbacks with Node's async exec were annoying to work with. Node now has execSync which is probably preferable to use.

[BurtHarris]

Thanks. Have I got this right? The simple approach is to use execSync, but I gather that won't achieve as much concurrency (not a particularly big issue for my case, everything else depends on building the tool sub-directory.

[mde]

That's right. Node folks can be really dogmatic about wanting everything async and streaming, but for a build tool manipulating stuff that's on local disk, async/streaming doesn't buy you a lot, and just makes your code needlessly complicated.