Consider automatically changing the settings based on yaml version

[SubaruArai]

Yaml's spec is quite complicated, and has evolved over time.

There are also some confusion around what version yamllint supports (#101), and default config between different yaml versions (#559, #540, #430, #344, #232, #247, #158).

May I suggest to add:

1. A config key to specify the targeted yaml version
   e.g. yaml-version: 1.1
2. Automatically change the default rules based on the yaml version
   e.g. if ver>=1.2, truthy.check-keys = true
3. (Optionally) add an option to automatically change rules based on the individual file's directive
   e.g. if %YAML 1.2, change config to 1.2.2

1 and 2 should be relatively easy, but 3 needs some consideration on how to implement.

Information: yaml spec changelog

[adrienverge]

Hello,

Although it's not 100% accurate, yamllint aims to support the latest version of the YAML specification (1.2.2). I believe that supporting multiple versions based on tags would be complicated, and cumbersome to most users.

PS: I don't see how the issues you pointed out (#559, #540, #430, #344, #232, #247, #158) are related to the YAML spec version.

[SubaruArai]

I believe that supporting multiple versions based on tags would be complicated, and cumbersome to most users.

Fair enough.

I don't see how the issues you pointed out (#559, #540, #430, #344, #232, #247, #158) are related to the YAML spec version.

I thought truthy's intend was to detect potential error between yaml 1.1/1.2 parsers.
The example {y: 1, yes: 2, on: 3, true: 4, True: 5} -> {y: 1, true: 5} will only happen in yaml<=1.1 parsers.

[adrienverge]

I thought truthy's intend was to detect potential error between yaml 1.1/1.2 parsers.
The example {y: 1, yes: 2, on: 3, true: 4, True: 5} -> {y: 1, true: 5} will only happen in yaml<=1.1 parsers.

@SubaruArai you're right. I've opened #650 to implement your 3rd suggestion (and while I disagree with the 2nd one, I like the 1st 👍).