Build enhancement for Conda

[eddelbuettel]

PR #710 (with SC 47400) brought in a small extension which included small Makevars (the Makefile snippet used by the R package) changes. As was seen in the subsequent release this was not fully Conda-compliant but additional tests helped determine a very small additional fix. A review by @jdblischak (who already tested this) would be nice but I cannot currently request one.

[jdblischak]

I tested this PR on my feedstock fork (commit, build)

• Good news: Enables the VFS-based read and write connections (PR Support VFS-based read and write connections #710) on osx-64
• Bad news: As I first discovered Friday when testing an earlier iteration, this recent change causes a test failure only on linux-aarch64 R 4.3. This is bizarre since it passes on R 4.2. Also, I triggered a feedstock build this morning off of the current main branch, and the linux-aarch64 R 4.3 tests passed fine, so it isn't due to an update in the Azure image

I still think we should merge this PR since it unblocks this new feature for the osx-64 conda binary. However, we'll need to do some troubleshooting before the next r-tiledb-feedstock release in order to figure out which test(s) to skip on linux-aarch64. From comparing the R 4.2 and 4.3 logs, it appears the error occurs on the 20th test in test_fragmentinfo.R

[jdblischak]

I suspect the error is happening here. Any reason to suspect this code would be consistently problematic for R 4.3 (but not 4.2) and linux-aarch64 (but not linux-64)? Worst case I'll just add a patch to the conda recipe to skip on linux-aarch64

TileDB-R/inst/tinytest/test_fragmentinfo.R

Lines 56 to 65 in e37db85

	D2 <- data.frame(keys = 11:20,
	groups = replicate(10, paste0(sample(LETTERS[1:4], 3), collapse="")),
	vals = sample(100, 10, TRUE))
	arr <- tiledb_array(uri, "WRITE")
	arr[] <- D2
	array_consolidate(uri) # written twice so consolidate
	rm(fraginf)
	fraginf <- tiledb_fragment_info(uri)

[eddelbuettel]

Two conversations here:

1. The PR itself which adds build to Conda breaks macOS builds (once that ever-so-helpful decides to unqueue itself and actually run anything). Ball in my court for this, will try to work out with mac-builder or rhub what needs to change.
2. The aarch64 aka arm64 issue: Strictly no idea, and 'old enough code' and tests to have been subjected to R 4.3.* before. No idea what's going on, no ability to do any work as I do not have access to aarch64 aka arm64 right now.

[eddelbuettel]

As owner of this issue and PR I took the liberty of marking the very interesting and passionate (but not really relevant here) discussion of another build platform as off-topic.

The current state (and primary puzzle) is that enabling Conda killed macOS. Bad trade-off.

[eddelbuettel]

So we now have the CI Actions back to ✔️ but there may be remaining Conda questions.

[jdblischak]

Testing the latest change that uses the env var CONDA_BUILD to configure the setup in the Azure macOS conda builds

https://dev.azure.com/jdblischak/feedstock-builds/_build/results?buildId=863&view=results

[eddelbuettel]

Yay! Looks like we won that battle:

The remaining fail is not new, and a continued puzzle. So onwards, gonna merge this now.