Change default behaviour for R package generator to recycle package version info

[rpkyle]

Currently, the R package generation code inserts an integer (which increments for each additional asset inserted into the dependency list) for the version number when none is available in __init__.py.

It would be safer to default to inserting the same version information as for the containing package, since this currently requires developer intervention and editing of internal.R after the package is generated. A (fictional) example:

.dashAwesomeExtensions_js_metadata <- function() {
  deps_metadata <- list(`dash_awesome_extensions` = structure(list(name = "dash_awesome_extensions",
                                                                   version = "2.0", src = list(href = NULL,
                                                                                               file = "deps"), meta = NULL,
                                                                   script = 'dash_awesome_extensions.min.js',
                                                                   stylesheet = NULL, head = NULL, attachment = NULL, package = "dashAwesomeExtensions",
                                                                   all_files = FALSE), class = "html_dependency"),
                        `dash_awesome_extensions` = structure(list(name = "dashAwesomeExtensions",
                                                                   version = "1", src = list(href = NULL,
                                                                                             file = "deps"), meta = NULL,
                                                                   script = NULL,
                                                                   stylesheet = 'fancify.css', head = NULL, attachment = NULL, package = "dashDesignKit",
                                                                   all_files = FALSE), class = "html_dependency"),
                        `dash_awesome_extensions` = structure(list(name = "dashAwesomeExtensions",
                                                                   version = "2", src = list(href = NULL,
                                                                                             file = "deps"), meta = NULL,
                                                                   script = NULL,
                                                                   stylesheet = 'stylize.css', head = NULL, attachment = NULL, package = "dashDesignKit",
                                                                   all_files = FALSE), class = "html_dependency"))
  return(deps_metadata)
}

This is important because of the way Dash dependencies are currently fetched via URL:

https://github.com/plotly/dashR/blob/a44050a27ba55056afed8ebac81e852ddf852e1f/R/utils.R#L196-L204

I propose that the default should be to replace version = "1" and version = "2" with version = "2.0" in the example above if version information for dependencies is not available within a generated package.

The relevant code block is here:

dash/dash/development/_r_components_generation.py

Lines 278 to 286 in d9ddc87

	# pylint: disable=consider-using-enumerate
	if len(alldist) > 1:
	for dep in range(len(alldist)):
	rpp = alldist[dep]["relative_package_path"]
	if "dash_" in rpp:
	dep_name = rpp.split(".")[0]
	else:
	dep_name = "{}".format(project_shortname)
	project_ver = str(dep)

@alexcjohnson

[alexcjohnson]

Let's take a step back here - AFAICT this version is just used in the cache-busting query param when we generate a <script> or <link> tag. Right now we include both version and file mod time in this query param ?v={}&m={}. We've had the version for a long time, mod time was added last fall in #387 - along with components_cache_max_age which we've since removed as unnecessary specifically because we have mod time in all the urls.

Is there really any reason we need both of these? Once we have mod time - which supports changes during development as well as users upgrading versions - isn't the version redundant? I propose we simply get rid of version and only use mod time.

[rpkyle]

From my point of view, I think 🔪 the v= part of the URL makes a lot of sense.

I've yet to run into any generated packages/libraries which contain assets where (a) the asset version ≠ the package version, and (b) it's important to maintain this distinct version information.

[rpkyle]

We've had the version for a long time, mod time was added last fall in #387 - along with components_cache_max_age which we've since removed as unnecessary specifically because we have mod time in all the urls.

Speaking of which, can I introduce a simple PR to 🔪 components_cache_max_age, targeted at dev?

[alexcjohnson]

Speaking of which, can I introduce a simple PR to 🔪 components_cache_max_age, targeted at dev?

In dashR you mean? Absolutely!