Passed --grep option persists across test runs

[segrey]

Let's consider the following project

// package.json
{
  "devDependencies": {
    "karma": "^1.7.0",
    "karma-jasmine": "^1.1.0",
    "karma-phantomjs-launcher": "^1.0.4",
    "jasmine-core": "^2.7.0"
  }
}

// karma.conf.js
module.exports = function(config) {
  config.set({
    frameworks: ['jasmine'],
    files: ['test.js'],
    reporters: ['progress'],
    port: 9876,
    browsers: ['PhantomJS'],
    singleRun: false
  })
};

// test.js
describe("suite1", function () {
  it("test1", function () {
  });
});

describe("suite2", function () {
  it("test2", function () {
  });
});

1. Start karma server

./node_modules/karma/bin/karma start

2. Run all karma tests in another terminal tab:

./node_modules/karma/bin/karma run
PhantomJS 2.1.1 (Linux 0.0.0): Executed 2 of 2 SUCCESS (0.039 secs / 0.001 secs)

Expected result

3. Run only suite1:

./node_modules/karma/bin/karma run -- '--grep=suite1'
PhantomJS 2.1.1 (Linux 0.0.0): Executed 1 of 2 (skipped 1) SUCCESS (0.038 secs / 0 secs)

Expected result

4. Run all karma tests again:

./node_modules/karma/bin/karma run
PhantomJS 2.1.1 (Linux 0.0.0): Executed 1 of 2 (skipped 1) SUCCESS (0.038 secs / 0.001 secs)

Unexpected result: only suite1 is run again.

Originally reported in karma-jasmine karma-runner/karma-jasmine#186 and in karma-mocha karma-runner/karma-mocha#196.

As pointed out by @maksimr, it's actually caused by modifying shared config.client.args in https://github.com/karma-runner/karma/blob/master/lib/middleware/runner.js#L51-L60

[rochapablo]

any update?