Do not use File.each_line iterator to ensure Files are closed

[bmulvihill]

Currently when running the specs on my Mac I get a Too many files open error. This is because when loading the DependencyGraph we are using the File.each_line iterator method, which does not close the file. This changes the DependencyGraph to use the File.each_line method which yields to a block, and properly closes the File.

[bew]

Note: can be written as if require_statement
But that's not related to this pr

[bew]

I don't get it, why this change fixes the file open issue? It basically doesn't change anything, it's just written differently

[bmulvihill]

@bew File.each_line without a block (which is what we are using currently) will not close the File since it delegates to the iterator method here: https://github.com/crystal-lang/crystal/blob/master/src/file.cr#L628, which in turn calls File.open without a block, which simply creates a new File. Using the block, as this PR does will delegate to https://github.com/crystal-lang/crystal/blob/master/src/file.cr#L574-L581 which ensures the file is closed

[bew]

Nice find! Can you open an issue on Crystal on this, I think this is a bug, or it should be documented

[faustinoaq]

@bmulvihill Nice, Thank you! 👍

[faustinoaq]

Travis on macOS is passing now 🎉