Cannot set property to of [object String] which has only a getter

[ilex0208]

Node version (or tell us if you're using electron or some other framework):6.11

ShellJS version (the most recent version/Github branch you see the bug on):0.7.8

Operating system:windows10

Description of the bug:Cannot set property to of [object String] which has only a getter

Example ShellJS command to reproduce the error: shelljs.rm

gulp.task('clean', () => {
  if (fs.existsSync(resolveCwd('lib'))) {
    shelljs.rm('-rf', resolveCwd('lib'));
  }
});

the error details is：
pipeMethods: [ 'cat','exec','grep', 'head', 'sed','sort','tail', 'to', 'toEnd', 'uniq' ]
cmd cat
cmd exec
cmd grep
cmd head
cmd sed
cmd sort
cmd tail
cmd to
error TypeError: Cannot set property to of [object String] which has only a getter
cmd toEnd
cmd uniq

that is to say, the 'to' method cannot set property!

[ilex0208]

When I used the version less than or equal to 0.6.0, it ran successfully

[nfischer]

Why are you trying to set the .to property? I don't even see where that's happening in your code.

Full stack trace?

[ilex0208]

I don't know why. I just used the code above in gulp.
The exception occurs in shelljs/src/common.js at line 151.
Source code:
pipeMethods.forEach(function (cmd) { that[cmd] = shellMethods[cmd].bind(that); });

[nfischer]

@ilex0208

I have no problems:

// gulpfile.js
var fs = require('fs');
var path = require('path');

var gulp = require('gulp');
var shelljs = require('shelljs');

gulp.task('clean', () => {
  if (fs.existsSync(path.resolve('lib'))) {
    shelljs.rm('-rf', path.resolve('lib'));
  }
});

$ ls -d lib/ &>/dev/null && echo 'The folder exists'
The folder exists
$ gulp clean
[21:57:20] Using gulpfile ~/foobar/gulpfile.js
[21:57:20] Starting 'clean'...
[21:57:20] Finished 'clean' after 6.33 ms
$ ls -d lib/ &>/dev/null || echo 'The folder was deleted'
The folder was deleted

Node v6.7.0
Gulp 3.9.1
ShellJS 0.7.8

[nfischer]

Can you try to repro with my steps?

[ilex0208]

I'm sorry that I can't reply you in time due to too many affairs to deal with recently.

Create a NPM module, directory is as follows

ptool/
  bin/
    s-tool.js
  index.js
  package.json

s-tool.js

    #!/usr/bin/env node

    const program = require('commander');

    program.on('--help', () => {
      console.log('  Usage:');
      console.log('  clean');
    });

    program.parse(process.argv);
    const task = program.args[0];

    if (!task) {
      program.help();
    } else {
      const gulp = require('gulp');
      require('../index');
      gulp.start(task);
    }

index.js

    const path = require('path');
    const fs = require('fs-extra');
    const shelljs = require('shelljs');

    const gulp = require('gulp');

    function resolveCwd() {
      const args = [].slice.call(arguments, 0);
      args.unshift(process.cwd());
      return path.join.apply(path, args);
    };

    // clean
    gulp.task('clean', () => {
      if (fs.existsSync(resolveCwd('lib'))) {
        shelljs.rm('-rf', resolveCwd('lib'));
      }
    });

    // other task ...

package.json

    {
        "name": "s-tool",
        "version": "1.0.0",
        "bin": {
            "s-tool": "./bin/s-tool.js"
        },
        "scripts": {
            "pub": "npm publish"
        },
        "license": "ISC",
        "dependencies": {
            "commander": "~2.9.0",
            "shelljs": "~0.7.8",
            "fs-extra": "^0.26.7",
            "gulp": "^3.9.1"
        }
    }

useage:

$ npm install -g s-tool

$ cd workspace
$ s-tool clean

If the folder lib exists, the error occurs.

However, when I used the version less than or equal to 0.6.0, it ran successfully

[nfischer]

I still have no repro on Linux.

Please provide a full stack trace from when you reproduce.

Also, please give a repro case using no other modules (only shelljs). I don't know if those other modules are tampering with us.

[nfischer]

@ilex0208 any update?

[nfischer]

Closing due to lack of response. Please ping this thread again if you can provide more information.

[zombieJ]

I found some package modify prototype of String makes pipeMethods add failed failed.

[nfischer]

@zombieJ we do not modify the prototype unless you import with shelljs/global (which we no longer recommend).

[zombieJ]

hi @nfischer ,
I do not mean shelljs change that. I mean other package change the prototype of String makes that[cmd] = shellMethods[cmd].bind(that) throw Cannot set property to of [object String] which has only a getter error.

[nfischer]

@zombieJ ah, thanks for explaining. I would argue this is a bug in the other package, since packages should not modify global prototypes.

Regardless, perhaps we can work around this with #651.

[ahungrynoob]

hi @nfischer ,
I do not mean shelljs change that. I mean other package change the prototype of String makes that[cmd] = shellMethods[cmd].bind(that) throw Cannot set property to of [object String] which has only a getter error.

The package you mean is colorful, right? https://github.com/lepture/colorful

[nfischer]

I don't believe there's anything for us to address here, kindly raise this issue with the colorful module.