regression bug: command line reporter-options parameter doesn't override mocha.opts

[stalb]

Prerequisites

• Checked that your issue hasn't already been filed by cross-referencing issues with the faq label
• Checked next-gen ES issues and syntax problems by using the same environment and/or transpiler configuration without Mocha to ensure it isn't just a feature that actually isn't supported in the environment in question or a bug in your code.
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Description

Mocha doesn't override reporter-options value defined in mocha.opts with the one defined on command line.

Steps to Reproduce

1. Define a mocha.ops file with reporter-options:

--recursive
--reporter=xunit
--reporter-options output=./test-reports/junit.xml

2. Call mocha using a different value for reporter-option

node node_modules/mocha/bin/mocha --reporter-options output=./test-reports/unit.xml

3. Verify that mocha has created ./test-reports/junit.xml and not ./test-reports/unit.xml

Expected behavior: [What you expect to happen]

Mocha should use the reporter-options specified on the command-line instead of the one defined in mocha.opts.

Actual behavior: [What actually happens]

Mocha use the reporter-options defined in mocha.opts instead of the one specified on the command-line.

Reproduces how often: [What percentage of the time does it reproduce?]
100%

Versions

• mocha: 6.0.0-6.1.4 (works fine with version 5.2.0) -- mocha is not installed globally
• node: 8.14.1 / 10.15.3 / 12.4.0
• Your operating system
  • name and version: windows 10 1903 / debian stretch
  • architecture (32 or 64-bit): 64bit
• Your shell (e.g., bash, zsh, PowerShell, cmd): PowerShell / bash

[juergba]

The reason could be: reporter-options is an array. So the values don't get overriden, but accumulated. When the parsed array is converted to an object, it's the last value who survives. I'm not sure though.

Could you check please, wether a string option like reporter gets overridden?

[stalb]

Yes, I've verified and reporter is overridden.

If the values of reporter-options are accumulated and only the latest value survives, then the problem is perhaps just in which the order there are accumulated.

Also I can use reporter-options on the command line or in mocha.opts (and that's works in both), the problem is when reporter-options is defined in both.

[juergba]

Thank you for your help. It's a bug.
reporter-options is a special case of option, the solution will be to make the array unique (with the first value, not the last one) before converting to an object.

Anyway you should not use "mocha.opts", it's considered legacy. Better to use one of the configuration files. This bug will remain activ though.

[outsideris]

I believe it only a bug with mocha.opts. but we already drop to support mocha.opts `.