Add params= to dbExecute S3 method

[r2evans]

Two fixes:

• while dbGetQuery(con, query, params=) works, dbExecute(con, query, params=) does not; and
• prevents both params= and parameters= from being passed as BigQueryResult(params=)

Includes NEWS, code, and unit-tests.

[hadley]

I think this would be cleaner if you had explicit params and parameters arguments and then used check_exclusive(params, parameters). (Then I think you can eliminate the do.call below)

[r2evans]

I can do that. Overall, the options:

1. Change bq_*(..., parameters=) to bq_*(..., params=). This was the "best" in my mind because it requires no check_exclusive() or other fancy checking, it "just worked naturally" with the ellipses. The reason I did not go with this was that I assumed that the overall package (or tidy) preference was towards parameters= for other reasons, regardless of the precedent set by DBI.
2. What I did (which was a workaround for not knowing about rlang::check_exclusive()).

I'll work on (2) unless you (quickly) come back with permission to implement (1) above.

[r2evans]

I think I need something other than check_exclusive(params, parameters).

With the dbSendQuery S3 method, I can't add parameters= in order to immediately check_exclusive(), yet when it calls BigQueryResult(params=params), the params= is no longer missing. I think I need to check for "parameters" %in% names(list(...)) to preclude this. Is there another way to pass-along missingness in a call like that?

[hadley]

Can you make a helper? This works for me:

f <- function(...) {
  check_params(...)
  list(...)
}

check_params <- function(param, parameters, ...) {
  check_exclusive(param, parameters, .require = FALSE)
}
f(param = 1)
f(parameters = 1)
f(parameters = 1, param = 2)

(But I may have forgotten a wrinkle that makes this challenging)

[r2evans]

Not really.

The issue is that dbGetQuery calls dbSendQuery which hard-codes params = params, so downstream functions see it as NULL instead of missing. I cannot add parameters= to the S3 method arguments without triggering an issue about a different S3 signature.

Instead, I've copied check_exclusive into a local function check_exclusive_missing_or_null that extends rlang::check_exclusive to add && !is.null(!!.x) inside the inject. (I changed a couple of other functions that are not being imported, no problem.)

[r2evans]

Two notes:

• I've worked around not having them, but since check_exclusive uses every and format_arg, it might be useful to useful to either add check_exclusive(..., .null=FALSE) or define check_exclusive_missing_or_null within rlang. I'm assuming neither for now.
• bigrquery does not import purrr directly but it is imported via rlang, so map_* is not immediately available. Would you like me to add @importFrom purrr ... to the imports, or are you fine with me shifting to vapply?

BTW, the function above resolves my intermediate issue, I'll push to the PR once I hear back from you on this.

[hadley]

Let me just take a swing at it myself.

[r2evans]

FTR,

check_exclusive_missing_or_null <- function(..., .require = TRUE, .frame = caller_env(), .call = .frame) {
  args <- enexprs(..., .named = TRUE)
  if (length(args) < 2) {
    cli::cli_abort("Must supply at least two arguments.")
  }
  if (!all(sapply(args, is.symbol))) {
    cli::cli_abort("`...` must be function arguments.")
  }
  present <- vapply(args, function(.x) inject(!base::missing(!!.x) && !is.null(!!.x), .frame), logical(1))
  n_present <- sum(present)
  if (n_present == 0) {
    if (.require) {
      args <- names(args)
      names(args) <- args
      args[] <- paste0("`", args, "`")
      enum <- oxford_comma(args)
      msg <- sprintf("One of %s must be supplied.", enum)
      cli::cli_abort(msg, call = .call)
    }
    else {
      return("")
    }
  }
  if (n_present == 1) {
    return(as_string(args[[which(present)]]))
  }
  args <- names(args)
  names(args) <- args
  args[] <- paste0("`", args, "`")
  enum <- oxford_comma(args)
  msg <- sprintf("Exactly one of %s must be supplied.", enum)
  if (n_present != length(args)) {
    enum <- oxford_comma(args[present], final = "and")
    msg <- c(msg, x = sprintf("%s were supplied together.", 
                              enum))
  }
  cli::cli_abort(msg, call = .call)
}