joins and attribute handling

[romainfrancois]

We have this test that is currently skipped in dev.

test_that("join takes LHS with warning if attributes inconsistent", {
  skip("we need to talk about this")
  df1 <- tibble(a = 1:2, b = 2:1)
  df2 <- tibble(
    a = structure(1:2, foo = "bar"),
    c = 2:1
  )

  expect_warning(
    out1 <- left_join(df1, df2, by = "a"),
    "Column `a` has different attributes on LHS and RHS of join"
  )
  expect_warning(out2 <- left_join(df2, df1, by = "a"))
  expect_warning(
    out3 <- left_join(df1, df2, by = c("b" = "a")),
    "Column `b`/`a` has different attributes on LHS and RHS of join"
  )

  expect_equal(attr(out1$a, "foo"), NULL)
  expect_equal(attr(out2$a, "foo"), "bar")
})

Do we still want this, or should it rather be something vctrs can deal with, and so be related to classes rather than free form attributes.

[hadley]

I think you can delete the test and file an issue on vctrs to make sure we think about free form attributes on data frames.

[hadley]

Done, since I'm in an issue closing frenzy 🤪