[R] String columns read lazily from readr error when transferred to an arrow table

[jonkeane]

Describe the bug, including details regarding any error messages, version, and platform.

On dev, here is a reprex:

arrow::as_arrow_table(
    readr::read_csv(readr::readr_example("chickens.csv"), lazy = TRUE), 
    sink = tempfile(fileext=".parquet")
)
#> Rows: 5 Columns: 4
#> ── Column specification ────────────────────────────────────────────────────────
#> Delimiter: ","
#> chr (3): chicken, sex, motto
#> dbl (1): eggs_laid
#> 
#> ℹ Use `spec()` to retrieve the full column specification for this data.
#> ℹ Specify the column types or set `show_col_types = FALSE` to quiet this message.
#> Error in Table__from_dots(dots, schema, option_use_threads()): No Set_elt found for ALTSTRING class [class: vroom_chr, pkg: vroom]

This wasn't a problem in our last release:

arrow::as_arrow_table(
    readr::read_csv(readr::readr_example("chickens.csv"), lazy = TRUE), 
    sink = tempfile(fileext=".parquet")
)
#> Rows: 5 Columns: 4
#> ── Column specification ────────────────────────────────────────────────────────
#> Delimiter: ","
#> chr (3): chicken, sex, motto
#> dbl (1): eggs_laid
#> 
#> ℹ Use `spec()` to retrieve the full column specification for this data.
#> ℹ Specify the column types or set `show_col_types = FALSE` to quiet this message.
#> Table
#> 5 rows x 4 columns
#> $chicken <string>
#> $sex <string>
#> $eggs_laid <double>
#> $motto <string>
#> 
#> See $metadata for additional Schema metadata

Component(s)

R

[thisisnic]

Hey, I think y'all already know this from reading the PR but I didn't understand it fully myself so wanted to add this reprex and clarify for my own understanding: this is not related to readr and is just altrep stuff, right? @jonkeane

library(arrow)

tf <- tempfile()
write.csv(mtcars, tf)
mtarrow <- read_csv_arrow(tf)

# exclude the line below and we don't have a problem
mtarrow
#>                         mpg cyl  disp  hp drat    wt  qsec vs am gear carb
#> 1            Mazda RX4 21.0   6 160.0 110 3.90 2.620 16.46  0  1    4    4
#> 2        Mazda RX4 Wag 21.0   6 160.0 110 3.90 2.875 17.02  0  1    4    4
#> 3           Datsun 710 22.8   4 108.0  93 3.85 2.320 18.61  1  1    4    1
#> 4       Hornet 4 Drive 21.4   6 258.0 110 3.08 3.215 19.44  1  0    3    1
#> 5    Hornet Sportabout 18.7   8 360.0 175 3.15 3.440 17.02  0  0    3    2
#> 6              Valiant 18.1   6 225.0 105 2.76 3.460 20.22  1  0    3    1
#> 7           Duster 360 14.3   8 360.0 245 3.21 3.570 15.84  0  0    3    4
#> 8            Merc 240D 24.4   4 146.7  62 3.69 3.190 20.00  1  0    4    2
#> 9             Merc 230 22.8   4 140.8  95 3.92 3.150 22.90  1  0    4    2
#> 10            Merc 280 19.2   6 167.6 123 3.92 3.440 18.30  1  0    4    4
#> 11           Merc 280C 17.8   6 167.6 123 3.92 3.440 18.90  1  0    4    4
#> 12          Merc 450SE 16.4   8 275.8 180 3.07 4.070 17.40  0  0    3    3
#> 13          Merc 450SL 17.3   8 275.8 180 3.07 3.730 17.60  0  0    3    3
#> 14         Merc 450SLC 15.2   8 275.8 180 3.07 3.780 18.00  0  0    3    3
#> 15  Cadillac Fleetwood 10.4   8 472.0 205 2.93 5.250 17.98  0  0    3    4
#> 16 Lincoln Continental 10.4   8 460.0 215 3.00 5.424 17.82  0  0    3    4
#> 17   Chrysler Imperial 14.7   8 440.0 230 3.23 5.345 17.42  0  0    3    4
#> 18            Fiat 128 32.4   4  78.7  66 4.08 2.200 19.47  1  1    4    1
#> 19         Honda Civic 30.4   4  75.7  52 4.93 1.615 18.52  1  1    4    2
#> 20      Toyota Corolla 33.9   4  71.1  65 4.22 1.835 19.90  1  1    4    1
#> 21       Toyota Corona 21.5   4 120.1  97 3.70 2.465 20.01  1  0    3    1
#> 22    Dodge Challenger 15.5   8 318.0 150 2.76 3.520 16.87  0  0    3    2
#> 23         AMC Javelin 15.2   8 304.0 150 3.15 3.435 17.30  0  0    3    2
#> 24          Camaro Z28 13.3   8 350.0 245 3.73 3.840 15.41  0  0    3    4
#> 25    Pontiac Firebird 19.2   8 400.0 175 3.08 3.845 17.05  0  0    3    2
#> 26           Fiat X1-9 27.3   4  79.0  66 4.08 1.935 18.90  1  1    4    1
#> 27       Porsche 914-2 26.0   4 120.3  91 4.43 2.140 16.70  0  1    5    2
#> 28        Lotus Europa 30.4   4  95.1 113 3.77 1.513 16.90  1  1    5    2
#> 29      Ford Pantera L 15.8   8 351.0 264 4.22 3.170 14.50  0  1    5    4
#> 30        Ferrari Dino 19.7   6 145.0 175 3.62 2.770 15.50  0  1    5    6
#> 31       Maserati Bora 15.0   8 301.0 335 3.54 3.570 14.60  0  1    5    8
#> 32          Volvo 142E 21.4   4 121.0 109 4.11 2.780 18.60  1  1    4    2

arrow_table(mtarrow)
#> Error in Table__from_dots(dots, schema, option_use_threads()): ALTSTRING objects of type <arrow::array_string_vector> are immutable

^{Created on 2024-07-27 with reprex v2.1.1}

[jonkeane]

Aaah that's a nice even more minimal reprex. I might pull that over so we don't need to add readr to our dependencies.

I had actually assumed our altrep vectors would be ok because they already had the ELT stuff, but clearly not!

[jonkeane]

Issue resolved by pull request 43351
#43351