Fix error reading remote workspace with version constraint

[shwetamurali]

Implementing the functionality that exists in cloud backend to remote as well to avoid errors on certain terraform commands when a version constraint is present.

CHANGELOG entry

• This change is user-facing and I added a changelog entry.
• This change is not user-facing.

[hashicorp-cla-app]

All committers have signed the CLA.

[SarahFrench]

👋🏻 Hi Shweta! I think this PR looks good, though I've not worked on the cloud/remote backends before so needed to dig in a little.

I believe before your PR users would see a "Malformed version" error if the workspace's Terraform version is a version constraint string, and after your PR's fixes users will only get an error if their Terraform version doesn't match the version constraint ("Terraform version mismatch").

Could you please add a new test case to cover this scenario? E.g. you could set the workspace's Terraform version to something like ">= 9.9.9" and assert about the error string in TestRemote_VerifyWorkspaceTerraformVersion_workspaceErrors. However if I've overlooked existing test coverage for the problem this PR is fixing please let me know.

Also, could you please resolve the CLA issue mentioned on the PR? Thanks!

[SarahFrench]

Thanks for the test! There's an edit required in the change file, but once that's done I'm happy to approve

[sebasslash]

Really nice work! 😄

@SarahFrench's initial suggestion was fantastic. I think we can further improve our tests to make sure we have all our bases covered.

[sebasslash]

We should create a table test to validate different version constraint scenarios. This style of structuring tests is a very common pattern when unit testing in Go. Example:

func TestRemote_VerifyWorkspaceTerraformVersion_versionConstraint(t *testing.T) {
  // configure backend 
  
  // Define our test case struct
  type testCase struct {
    terraformVersion string
    versionConstraint string
    shouldSatisfy bool
  }
  
  // Create a slice of test cases
  testCases := []testCase{
    {
       terraformVersion: "1.8.0",
       terraformVersionConstraint: "> 1.9.0",
       shouldSatisfy: false,
    },
    {
       terraformVersion: "1.10.1",
       terraformVersionConstraint: "~> 1.10.0",
       shouldSatisfy: true,
    },   
    { 
       // etc
    },
  }
  
  // Now we loop through each test case, utilizing the values of each case
  // to setup our test and assert accordingly.
  for _, tc := range testCases {
    // Mock the Terraform version
    // Update the mocked workspace with the constraint
    // Call `VerifyWorkspaceTerraformVersion` and assert any diagnostics depending on whether
    // shouldSatisfy is true or not
  }
}

[SarahFrench]

Also, if these tests are applicable to both the remote and cloud backends then maybe those changes should be propagated to the cloud backend? That could be saved for a separate PR, though.