Out of order execution when model selectors are applied

[drewbanin]

Issue

Issue description

When models are selected with --models, dbt can execute models in the incorrect order. This specifically occurs when a model which is not included in the run provides the transitive edge between two models which are included in the run.

Results

dbt ran the models in the wrong order. If this is the initial run, then dbt can fail with a "table does not exist" error. If it's a subsequent run, then the behavior is effectively undefined: The two models run in random order and can fail (or succeed) depending on the state of the database and how long the models take to run.

System information

The output of dbt --version:

0.12.2

The operating system you're running on: macOS, py27/36

Steps to reproduce

dbt init outoforder
cd outoforder
mkdir models/included models/excluded
echo "select 1 as id" > models/included/base.sql
echo "select * from {{ ref('excluded_model') }}" > models/included/debug.sql
echo "select * from {{ ref('base') }}" > models/excluded/excluded_model.sql

dbt run --models included.*

Note that when run multiple times, debug and base will run simultaneously whereas base should always run first.