[tfswitch-parity] Auto-install if a .tf file contains a Terraform required_version block

[kvendingoldo]

Describe the solution you'd like
Please replicate this feature from tfswitch. https://tfswitch.warrensbox.com/Quick-Start/#use-versiontf-file

Additional context
It's backport of the original issue from tofuenv: tofuutils/tofuenv#31
cc @skyzyx

[dvaumoron]

The default behaviour (when no .opentofu-version or .terraform-version files are found, depending on which proxy command you use) of current version is latest-allowed which scan .tf and .tf.json files to extract required_version constraints.

[giner]

The default behaviour (when no .opentofu-version or .terraform-version files are found, depending on which proxy command you use) of current version is latest-allowed which scan .tf and .tf.json files to extract required_version constraints.

This works (surprisingly) only if the default version is not defined

[dvaumoron]

Hi @giner ,

starting to scan the whole folder before simpler checks does not seem accurate to me.

the resolution ordrer for reference : https://github.com/tofuutils/tenv#project-binaries

tenv look for a TOFUENV_TOFU_DEFAULT_VERSION environment variable after most files have been tested.

[giner]

starting to scan the whole folder before simpler checks does not seem accurate to me

From implementation perspective this makes sense, however from UX perspective the current behavior is not optimal an not vey obvious. If required_version was considered earlier (with higher priority) we wouldn't need .xxx-version files in most cases.

tenv look for a TOFUENV_TOFU_DEFAULT_VERSION environment variable after most files have been tested.

I believe this should be changed. Here's a proposal https://github.com/orgs/tofuutils/discussions/7#discussioncomment-11941382