load_tool: when no version or incorrect cwlVersion is found, create fatal error

[manu-chroma]

Fixes #341, #140

[tetron]

If no version number is found it should be a fatal error.

[manu-chroma]

@tetron No such fallback should be provided?
#482 (comment)

[mr-c]

#482 (comment) :-)

[tetron]

Yes, instead of falling back it should be a fatal error. We don't want to encourage people to start writing files cwl where we can't identify the version, it makes spec evolution much harder.

[manu-chroma]

Thanks. Done 👍

[manu-chroma]

testing on the example @FarahZKhan mentioned #482 (comment)

(venv3) [venv3] $ cwltool --pack hello-param.cwl params.yaml
/home/manu/github/cwltool/venv3/bin/cwltool 1.0.20170717092913
Resolved 'hello-param.cwl' to 'file:///home/manu/github/test_cwl_runner/workflows/workflows/hello/hello-param.cwl'
Tool definition failed validation:
No cwlVersion found. Use the following syntax in your CWL workflow to declare version: cwlVersion: <version>

[manu-chroma]

When using cwlVersion: v0.1 in the workflow.

(venv3) [venv3] ~/github/cwltool/tests · (version_fix±) $ cwltool wf/wrong_cwlVersion.cwl                     23:10:22
/home/manu/github/cwltool/venv3/bin/cwltool 1.0.20170723153038
Resolved 'wf/wrong_cwlVersion.cwl' to 'file:///home/manu/github/cwltool/tests/wf/wrong_cwlVersion.cwl'
Tool definition failed validation:
'cwlVersion' not valid. Supported CWL versions are: 
draft-2
draft-3
draft-3.dev1
draft-3.dev2
draft-3.dev3
draft-3.dev4
draft-3.dev5
draft-4.dev1
draft-4.dev2
draft-4.dev3
v1.0
v1.0.dev4
v1.1.0-dev1

[manu-chroma]

Also, added tests :)

[mr-c]

I approve, though this does not fix #482 (that can happen in another PR) -- thanks!

[manu-chroma]

With this PR merged:
cwlVersion: cwl:draft-3 throws validation exception.
cwlVersion: draft-3 works as expected.

Is this behavior acceptable?