[Elixir] fix parameter name with {{baseName}}

[ePaul]

PR checklist

• Read the contribution guildelines.
• Ran the shell/batch script under ./bin/ to update Petstore sample so that CIs can verify the change.
  → bin/elixir-petstore.sh
• Filed the PR against the correct branch: master for non-breaking changes

Description of the PR

This fixes (or hopes to fix) part of #4898 for the elixir generator.

The problem likely occurred when a query/form/header parameter name (as declared in the OpenAPI definition) is of a form which doesn't match the form used in Elixir, or is a reserved word there. In this case the parameter gets renamed for use in the code, and the algorithm for including the parameter in the request uses the sanitized name instead of the original one.

This commit changes the replacement to using {{baseName}} (which is the original name of the parameter definition as parsed from the API definition) instead of {{paramName}} (which is the sanitized version of the parameter name).

There are some places in the Petstore samples where this makes some difference, to me it looks like the new ones are more sensible.

I don't know anything about Elixir (don't even have a compiler on my computer), so this needs intensive review by Elixir experts. /cc @niku

[wing328]

@niku I wonder if you can help us understanding the following

query_params = [{{^queryParams.isEmpty}}query: [{{#queryParams}}{{^-first}}, {{/-first}}{:"{{paramName}}", {{#underscored}}{{paramName}}{{/underscored}}}{{/queryParams}}]{{/queryParams.isEmpty}}]
header_params = [{{^headerParams.isEmpty}}header: [{{#headerParams}}{{^-first}}, {{/-first}}{:"{{paramName}}", {{#underscored}}{{paramName}}{{/underscored}}}{{/headerParams}}]{{/headerParams.isEmpty}}]

Is {{#underscored}}{{paramName}}{{/underscored}} the variable name in Elixir or the original variable name (e.g. modified-date, AccountName) defined in the spec? Thanks.

[niku]

Hi, I'm sorry for the late reply.
I will check this PR later probably some time today or tomorrow.

[niku]

Is {{#underscored}}{{paramName}}{{/underscored}} the variable name in Elixir or the original variable name (e.g. modified-date, AccountName) defined in the spec?

It should be a variable name in Elixir like account_name not like AccountName.

  def login_user(username, password) do
    method = [method: :get]
    url = [url: "/user/login"]
    query_params = [query: [{:"username", username}, {:"password", password}]]
    #                                    ^^^^^^^^^^                ^^^^^^^^^
    # Thease are the parts that generated by {{#underscored}}{{paramName}}{{/underscored}}.
    # They have to equal the argument of the function.