[BUG] postpack script runs BEFORE the tarball has been generated and moved to its final destination.

[palavrov]

Current Behavior:

postpack script runs BEFORE the tarball has been generated and moved to its final destination.

Expected Behavior:

As is in the documentation:

Runs AFTER the tarball has been generated and moved to its final destination.

Steps To Reproduce:

copy this package.json to an empty directory

{
  "name": "postpacktest",
  "version": "1.0.0",
  "scripts": {
    "prepack": "rm postpacktest-1.0.0.tgz",
    "postpack": "ls -al"
  }
}

run:
npm pack
and then
ls -al

Environment:

*nix

[nlf]

what version of node? what version of npm? some key pieces of our issue template are missing here, but I'm unable to reproduce this in npm@7.0.13

[palavrov]

$ node --version
v15.1.0

$ npm --version
7.0.8

If you check the source will see that, libnpmpack is called here:

cli/lib/pack.js

Line 41 in 65bdbb2

const tarballData = await libpack(arg, opts)

which calls post pack life cycle script here:
https://github.com/npm/libnpmpack/blob/c4f8b823e9f206113bef3e59419f7aa93c619acb/index.js#L33
and then the file will be written here:

cli/lib/pack.js

Line 45 in 65bdbb2

await writeFile(filename, tarballData)

[nlf]

indeed! good find, thanks for reporting it!

[palavrov]

IMHO one easy fix will be to conditionally of dryrun pass the output path to the libnpmpack method as parameter so it could write the file if the path is not null/undefined between the pre and post pack life cycle scripts execution.

[palavrov]

BTW publish command suffer from the same problem as it doesn't rely on the pack command but call libnpmpack directly and if I'm not wrong it doesn't write the .tgz file on the disk at all.

Which is another problem as it breaks my postpack hooks to cleanup package.json content on pack and publish - the only way was to pipe the .tgz archive on postpack.

[flavioleggio]

Still not working on node v16.13.0.
Any updates?

[martin770]

I updated my project from npm 6.14.13 (node.js 14.17.1) to npm 8.4.1 (node.js 16.13.2), and am also running into this issue. I have a 'prepack' script to run eslint and unit tests, and I have a 'postpack' script to move the packaged tarball into a different folder. After upgrading npm and running npm pack, my postpack script fails to move the .tgz file because it has not yet been created when the postpack step triggers. If I comment out the code in my postpack script, I can see my script run and THEN the tarball is created.

According to the npm documentation
postpack: Runs AFTER the tarball has been generated but before it is moved to its final destination (if at all, publish does not save the tarball locally)