Tune mount when description is changed

[jasonodonnell]

The vault_mount resource has a bug where if you change the description of the mount, it deletes the mount and recreates. This is due to the parameter having ForceNew: true enabled in the schema.

Instead this should be tuning the description instead of deleting the resource when updating the mount description.

Fixes #909.
Fixes #782.

[tvoran]

Works for me 👍

Only thought it is it might be good to update testResourceMount_updateConfig and testResourceMount_updateCheck() to actually update the mount description to something different than the initialConfig. i.e.

diff --git a/vault/resource_mount_test.go b/vault/resource_mount_test.go
index 07a6dcde..79341efb 100644
--- a/vault/resource_mount_test.go
+++ b/vault/resource_mount_test.go
@@ -241,7 +241,7 @@ func testResourceMount_initialCheck(cfg mountConfig) resource.TestCheckFunc {
 resource "vault_mount" "test" {
        path = "remountingExample"
        type = "kv"
-       description = "Example mount for testing"
+       description = "Updated example mount for testing"
        default_lease_ttl_seconds = 7200
        max_lease_ttl_seconds = 72000
        options = {
@@ -270,7 +270,7 @@ func testResourceMount_updateCheck(s *terraform.State) error {
                return fmt.Errorf("error reading back mount: %s", err)
        }
 
-       if wanted := "Example mount for testing"; mount.Description != wanted {
+       if wanted := "Updated example mount for testing"; mount.Description != wanted {
                return fmt.Errorf("description is %v; wanted %v", mount.Description, wanted)
        }
 

[jasonodonnell]

This test is failing https://github.com/hashicorp/terraform-provider-vault/blob/master/vault/resource_ssh_secret_backend_ca_test.go#L29-L48 but unsure why. If I run a similar test manually I'm getting a plan:

Terraform will perform the following actions:
  # vault_mount.test will be updated in-place
  ~ resource "vault_mount" "test" {
        accessor                  = "ssh_9b0f7347"
        default_lease_ttl_seconds = 0
      ~ description               = "something" -> "something else"
        external_entropy_access   = false
        id                        = "ssh"
        local                     = false
        max_lease_ttl_seconds     = 0
        options                   = {}
        path                      = "ssh"
        seal_wrap                 = false
        type                      = "ssh"
    }
Plan: 0 to add, 1 to change, 0 to destroy.

[jasonodonnell]

After some review, @catsby and I agreed to remove the broken test because:

• there's a bug in our current version of the terraform SDK that we can't resolve (upgrading introduces many changes beyond the scope of this PR)
• the test wasn't particularly valuable.

Both @catsby and I manually verified the changes are good.