std.thisFile returning empty string

[RixTmobilender]

Apologies if this issue is best served in the upstream jsonnet repo.
I believe I'm hitting a bug where std.thisFile is returning an empty string, I can't intantiate helm correctly due to this behavior.

the following snippet:

helm+: {
  local tanka = import "github.com/grafana/jsonnet-libs/tanka-util/main.libsonnet",
  local helm = tanka.helm.new(std.thisFile),
  executable: helm,
  debug_field: std.thisFile,
  charts_folder: "./charts/", // this is relative to the file where we instantiate executable (right here above)
},

is producing:

"helm": {
  "charts_folder": "./charts/",
  "debug_field": "",
  "executable": {
    "#new": {
      "function": {
        "args": [
          {
            "default": null,
            "name": "calledFrom",
            "type": "string"
          }
        ],
        "help": "`new` initiates the `helm` object. It must be called before any `helm.template` call:\n \u003e ```jsonnet\n \u003e // std.thisFile required to correctly resolve local Helm Charts\n \u003e helm.new(std.thisFile)\n \u003e ```\n"
      }
    },
    "_config": {}
  }
},

Any idea why this might occur and if it's related to tanka?
The rest of my snippet for reference
launcher.jsonnet.txt

Actually trying to use the instantiated helm to template results in an error code:
Error: evaluating jsonnet: RUNTIME ERROR: helmTemplate: 'opts.calledFrom' is unset or empty.

I'm currently working around this by manually writing the filepath to the current file, it works flawlessly.

[Duologic]

Did you try it with plain jsonnet?

[RixTmobilender]

Right (doh), I just did and it seems I only get blank strings when using tanka (I'm currently using latest release v0.18.1)
Notice the value of $.rendered_tanka_env.data.helm.debug_field

Using the attached launcher.jsonnet I ran:

• $ jsonnet --tla-str cluster_category=devopsservices --tla-str env_override=local --tla-str env_name=prerequisites launcher.jsonnet -J lib -J vendor
  and:
• $ tk --tla-str cluster_category=devopsservices --tla-str env_override=local --tla-str env_name=prerequisites launcher.jsonnet eval

Which yielded respectively:

•   {
      "rendered_tanka_env": {
         "data": {
            "helm": {
               "charts_folder": "./charts/",
               "debug_field": "launcher.jsonnet",
               "executable": {
                  "#new": {
                     "function": {
                        "args": [
                           {
                              "default": null,
                              "name": "calledFrom",
                              "type": "string"
                           }
                        ],
                        "help": "`new` initiates the `helm` object. It must be called before any `helm.template` call:\n > ```jsonnet\n > // std.thisFile required to correctly resolve local Helm Charts\n > helm.new(std.thisFile)\n > ```\n"
                     }
                  },
                  "_config": { }
               }
            }
         }
      }
   }

and:

•   {
     "rendered_tanka_env": {
       "data": {
         "helm": {
           "charts_folder": "./charts/",
           "debug_field": "",
           "executable": {
             "#new": {
               "function": {
                 "args": [
                   {
                     "default": null,
                     "name": "calledFrom",
                     "type": "string"
                   }
                 ],
                 "help": "`new` initiates the `helm` object. It must be called before any `helm.template` call:\n \u003e ```jsonnet\n \u003e // std.thisFile required to correctly resolve local Helm Charts\n \u003e helm.new(std.thisFile)\n \u003e ```\n"
               }
             },
             "_config": {}
           }
         }
       }
     }
   }