if buildOnSave is on: build using -i

[mattetti]

This PR addresses the compilation performance optimization discussed in #673.

Installing the built packages improves following compilations since packages are only rebuilt if they changed.
If the current package is a main package, the installation is skipped to avoid installing executable binaries.

I had to tweak a util method that was scanning text files to find the package and the imports. Unfortunately this util wasn't tracking the name of the package. I needed the package name to check if the -i flag should be used or not.

[mattetti]

@ramya-rao-a would you mind helping me understand what's wrong with the test suite? I seem to have broken something on macOS. The failures don't make too much sense to me :(

[ramya-rao-a]

@mattetti The 2 tests are failing because they are not getting back expected errors from go build.
You are reading the file using fs.readFile and calling the runTool in the callback. By the time the callback is called, the test has already completed, and so does not get the results of go build.

Here is what you can try:

let buildPromise = new Promise<ICheckResult[]>((resolve, reject) => {
    fs.readFile(filename. 'utf8', (err, data) => {
        .....
        runTool(....).then(result => return resolve(result), err => return reject(err));
    }
});
runningToolsPromises.push(buildPromise);

[mattetti]

perfect thank you! I'll give it a try

[mattetti]

@ramya-rao-a PR updated, tests are now passing, thanks for your help!

Note, this PR is pending the resolution of the discussion happening there: #673