Thanks for linking the source code. It is a valid concern. As a short-term mitigation, we can modify the condition:
(param.ValidationMin == 0 && param.ValidationMax != 0) || (param.ValidationMin != 0 && param.ValidationMax == 0)

It won't cover the edge case Min = Max = 0, but it seems to be rare. Do you think that it is worth applying it in your PR, @spikecurtis?

Nevertheless, I agree that the proper fix requires changes in the persistence layer (nullable column).

I agree that Min = Max = 0 isn't an important case, as the parameter then is just a fixed value.

However, (param.ValidationMin == 0 && param.ValidationMax != 0) || (param.ValidationMin != 0 && param.ValidationMax == 0) has the drawback that it's hard express a min without a max or vice versa, e.g. v >= 0.

In practice there is almost always a min or max, e.g. max int32 or whatever, but it's kind of obnoxious to force template authors to provide both.

I think we should just do the proper fix in a separate PR and not absorb it into the one I'm currently working on.

I think we should just do the proper fix in a separate PR and not absorb it into the one I'm currently working on.

👍

Fortunately, the fix should not have implications on the API compatibility (/rich-parameters) as ValidationMin and ValidationMax have omitempty annotation in:

	ValidationMin        int32                            `json:"validation_min,omitempty"`
	ValidationMax        int32                            `json:"validation_max,omitempty"`

FYI: I'm working on fixing this issue.

However, (param.ValidationMin == 0 && param.ValidationMax != 0) || (param.ValidationMin != 0 && param.ValidationMax == 0) has the drawback that it's hard express a min without a max or vice versa, e.g. v >= 0.

The problem has its roots in the terraform-provider-coder, which assumes that both properties (min and max) come together.

Resolved in coder/terraform-provider-coder#122

I'm afraid that I found another issue. When terraform is resolving the plan it ends up with zero-populated values, which is odd as parameterDataSource() fixes all zero -> nil values.

Fragment of the .tfplan file:

{
            "address": "data.coder_parameter.compute_instances_7",
            "mode": "data",
            "type": "coder_parameter",
            "name": "compute_instances_7",
            "provider_name": "registry.terraform.io/coder/coder",
            "schema_version": 0,
            "values": {
              "default": "3",
              "description": "Let's set the expected number of instances.",
              "display_name": null,
              "icon": "/icon/rubymine.svg",
              "id": "a7564661-442f-4ee6-a3d0-49fcdda08839",
              "legacy_variable": null,
              "legacy_variable_name": null,
              "mutable": true,
              "name": "Compute instances",
              "option": null,
              "optional": true,
              "type": "number",
              "validation": [
                {
                  "error": "",
                  "max": 8,
                  "min": 0,
                  "monotonic": "increasing",
                  "regex": ""
                }
              ],
              "value": "3"
            },
            "sensitive_values": {
              "validation": [
                {}
              ]
            }
          }

I'm investigating it. It doesn't make sense as display_name is null, legacy_variable_name too, but min not...

BTW Is that what you meant @mafredri?