Using a variable in a link href

[robfig]

This template:

{namespace main}

{template .main}
{@param appName: string}
    <link rel="stylesheet"
          type="text/css"
          href="/{$appName}/public/stylesheets/styles.css">
{/template}

Fails to compile with this error:

/Users/robfig/closure-templates/test.soy:7: error: Invalid or ambiguous syntax prevents Soy from escaping this template correctly:
- TrustedResourceUris containing dynamic content must have a fixed scheme (https) and host using one of the following formats:
  * https://foo/
  * //foo/
  * /foo
or move the calculation of this URL outside of the template and use an ordaining API.
7:           href="/{$appName}/public/stylesheets/styles.css">
                   ^

I don't understand why -- it is exactly the third format mentioned in the error message. What am I doing wrong?

EDIT: Here are other URLs that result in the same error:

• /foo/{$appName}/public/stylesheets/styles.css
• //{$domain}/foo
• http://localhost:3000/app/{$appName}.css

[robfig]

To reproduce locally, checkout commit robfig@caaba74 and run bazel run :CompileSoy -- `pwd`/test.soy from the repo root.

[robfig]

Pinging @emspishak for any thoughts -- is this working as intended?

[lpellegr]

@robfig I am quite new to Closure templates and experienced a similar issue. A solution that is working is to pass the URI to set as a param of type trusted_resource_uri and then using it as the href attribute value.