Proposal: Refactor output on solver error to only output the most relevant information

[maxmeyer]

What version of Go (go version) and dep (git describe --tags) are you using?

Go: 1,.8.3
Dep: v0.2.1-6-gc1aba4d

What dep command did you run?

% dep ensure

1. I use libbeat which has a lot of releases
2. I've got an unmatched dependency due to an library downgrade which leads to an error
3. I oversaw that error because of the amount of output in default mode

What did you expect to see?

The relevant line is:

# =>         v5.5.1: Could not introduce github.com/elastic/beats@v5.5.1, as its subpackage github.com/elastic/beats/libbeat/cmd is missing. (Package is required by (root).)

This tolds me, that I've got an unmet dependency. What I propose is, that only this line is printed to STDERR/STDOUT if:

• The version/branch string matches
• A dependency error occured

I would love to see all the output on -v, but without -v only the relevant lines.

What did you see instead?

# => Root project is "git.example.org/group/project"
# =>  10 transitively valid internal packages
# =>  14 external packages imported from 10 projects
# => 
# => ensure Solve(): No versions of github.com/elastic/beats met constraints:
# =>         v5.5.1: Could not introduce github.com/elastic/beats@v5.5.1, as its subpackage github.com/elastic/beats/libbeat/cmd is missing. (Package is required by (root).)
# =>         v5.5.0: Could not introduce github.com/elastic/beats@v5.5.0, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.4.3: Could not introduce github.com/elastic/beats@v5.4.3, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.4.2: Could not introduce github.com/elastic/beats@v5.4.2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.4.1: Could not introduce github.com/elastic/beats@v5.4.1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.4.0: Could not introduce github.com/elastic/beats@v5.4.0, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.3.3: Could not introduce github.com/elastic/beats@v5.3.3, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.3.2: Could not introduce github.com/elastic/beats@v5.3.2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.3.1: Could not introduce github.com/elastic/beats@v5.3.1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.3.0: Could not introduce github.com/elastic/beats@v5.3.0, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.2.2: Could not introduce github.com/elastic/beats@v5.2.2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.2.1: Could not introduce github.com/elastic/beats@v5.2.1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.2.0: Could not introduce github.com/elastic/beats@v5.2.0, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.1.2: Could not introduce github.com/elastic/beats@v5.1.2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.1.1: Could not introduce github.com/elastic/beats@v5.1.1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.0.2: Could not introduce github.com/elastic/beats@v5.0.2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.0.1: Could not introduce github.com/elastic/beats@v5.0.1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.0.0: Could not introduce github.com/elastic/beats@v5.0.0, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v1.3.1: Could not introduce github.com/elastic/beats@v1.3.1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v1.3.0: Could not introduce github.com/elastic/beats@v1.3.0, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v1.2.3: Could not introduce github.com/elastic/beats@v1.2.3, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v1.2.2: Could not introduce github.com/elastic/beats@v1.2.2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v1.2.1: Could not introduce github.com/elastic/beats@v1.2.1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v1.2.0: Could not introduce github.com/elastic/beats@v1.2.0, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v1.1.2: Could not introduce github.com/elastic/beats@v1.1.2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v1.1.1: Could not introduce github.com/elastic/beats@v1.1.1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v1.1.0: Could not introduce github.com/elastic/beats@v1.1.0, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v1.0.1: Could not introduce github.com/elastic/beats@v1.0.1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v1.0.0: Could not introduce github.com/elastic/beats@v1.0.0, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v0.5.0: Could not introduce github.com/elastic/beats@v0.5.0, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v0.4.3: Could not introduce github.com/elastic/beats@v0.4.3, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v0.4.2: Could not introduce github.com/elastic/beats@v0.4.2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v0.4.1: Could not introduce github.com/elastic/beats@v0.4.1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v0.4.0: Could not introduce github.com/elastic/beats@v0.4.0, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v0.3.3: Could not introduce github.com/elastic/beats@v0.3.3, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v0.3.2: Could not introduce github.com/elastic/beats@v0.3.2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v0.3.1: Could not introduce github.com/elastic/beats@v0.3.1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v0.3.0: Could not introduce github.com/elastic/beats@v0.3.0, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v0.2.2: Could not introduce github.com/elastic/beats@v0.2.2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         0.2.1: Could not introduce github.com/elastic/beats@0.2.1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v0.2.1: Could not introduce github.com/elastic/beats@v0.2.1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v0.2.0: Could not introduce github.com/elastic/beats@v0.2.0, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v0.1.1: Could not introduce github.com/elastic/beats@v0.1.1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v0.1.0: Could not introduce github.com/elastic/beats@v0.1.0, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v6.0.0-alpha2: Could not introduce github.com/elastic/beats@v6.0.0-alpha2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v6.0.0-alpha1: Could not introduce github.com/elastic/beats@v6.0.0-alpha1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.0.0-rc1: Could not introduce github.com/elastic/beats@v5.0.0-rc1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.0.0-beta1: Could not introduce github.com/elastic/beats@v5.0.0-beta1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.0.0-alpha5: Could not introduce github.com/elastic/beats@v5.0.0-alpha5, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.0.0-alpha4: Could not introduce github.com/elastic/beats@v5.0.0-alpha4, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.0.0-alpha3: Could not introduce github.com/elastic/beats@v5.0.0-alpha3, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.0.0-alpha2: Could not introduce github.com/elastic/beats@v5.0.0-alpha2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v5.0.0-alpha1: Could not introduce github.com/elastic/beats@v5.0.0-alpha1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v1.0.0-rc2: Could not introduce github.com/elastic/beats@v1.0.0-rc2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v1.0.0-rc1: Could not introduce github.com/elastic/beats@v1.0.0-rc1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v1.0.0-beta4: Could not introduce github.com/elastic/beats@v1.0.0-beta4, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v1.0.0-beta3: Could not introduce github.com/elastic/beats@v1.0.0-beta3, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v1.0.0-beta2: Could not introduce github.com/elastic/beats@v1.0.0-beta2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         master: Could not introduce github.com/elastic/beats@master, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         1.0.0: Could not introduce github.com/elastic/beats@1.0.0, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         1.0.0-beta2: Could not introduce github.com/elastic/beats@1.0.0-beta2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         1.0.0-beta3: Could not introduce github.com/elastic/beats@1.0.0-beta3, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         1.0.0-beta4: Could not introduce github.com/elastic/beats@1.0.0-beta4, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         1.0.0-rc1: Could not introduce github.com/elastic/beats@1.0.0-rc1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         1.0.0-rc2: Could not introduce github.com/elastic/beats@1.0.0-rc2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         1.0.0.Beta1: Could not introduce github.com/elastic/beats@1.0.0.Beta1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         1.0.1: Could not introduce github.com/elastic/beats@1.0.1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         1.1: Could not introduce github.com/elastic/beats@1.1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         1.2: Could not introduce github.com/elastic/beats@1.2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         1.3: Could not introduce github.com/elastic/beats@1.3, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         5.0: Could not introduce github.com/elastic/beats@5.0, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         5.1: Could not introduce github.com/elastic/beats@5.1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         5.2: Could not introduce github.com/elastic/beats@5.2, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         5.3: Could not introduce github.com/elastic/beats@5.3, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         5.4: Could not introduce github.com/elastic/beats@5.4, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         5.5: Could not introduce github.com/elastic/beats@5.5, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         5.6: Could not introduce github.com/elastic/beats@5.6, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         6.0: Could not introduce github.com/elastic/beats@6.0, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         6.x: Could not introduce github.com/elastic/beats@6.x, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         dedemorton-patch-1: Could not introduce github.com/elastic/beats@dedemorton-patch-1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         license_bsd_clauses: Could not introduce github.com/elastic/beats@license_bsd_clauses, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         revert-4501-master: Could not introduce github.com/elastic/beats@revert-4501-master, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         x-exec-lookup: Could not introduce github.com/elastic/beats@x-exec-lookup, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.
# =>         v1.0.0.Beta1: Could not introduce github.com/elastic/beats@v1.0.0.Beta1, as it is not allowed by constraint ^5.5.1 from project git.example.org/group/project.

[sdboyer]

yep, this sort of case is one of the very first things i want to tackle with #288. reporting failures is difficult in general, but we can at least beat it back case by case for the major ones. they're coming up soon on the roadmap, but i personally probably won't be able to get to them for a few months.

however, i'm more than happy to guide and advise contributors interested in helping 😉