Can't ungroup using group_by()

[davidchall]

I found an inconsistency between dplyr and dbplyr with how grouping works.

If you have a grouped tibble and call group_by() (i.e. with no grouping variables), it should return an ungrouped tibble. This makes it easier to write functions that restore original groupings (e.g. group_by(!!!groups(.data))).

library(tidyverse)
library(dbplyr)

# ungrouped output
storms %>% group_by(status) %>% group_by()
#> # A tibble: 10,010 x 13
#>    name   year month   day  hour   lat  long status      category  wind pressure
#>    <chr> <dbl> <dbl> <int> <dbl> <dbl> <dbl> <chr>       <ord>    <int>    <int>
#>  1 Amy    1975     6    27     0  27.5 -79   tropical d… -1          25     1013
#>  2 Amy    1975     6    27     6  28.5 -79   tropical d… -1          25     1013
#>  3 Amy    1975     6    27    12  29.5 -79   tropical d… -1          25     1013
#>  4 Amy    1975     6    27    18  30.5 -79   tropical d… -1          25     1013
#>  5 Amy    1975     6    28     0  31.5 -78.8 tropical d… -1          25     1012
#>  6 Amy    1975     6    28     6  32.4 -78.7 tropical d… -1          25     1012
#>  7 Amy    1975     6    28    12  33.3 -78   tropical d… -1          25     1011
#>  8 Amy    1975     6    28    18  34   -77   tropical d… -1          30     1006
#>  9 Amy    1975     6    29     0  34.4 -75.8 tropical s… 0           35     1004
#> 10 Amy    1975     6    29     6  34   -74.8 tropical s… 0           40     1002
#> # … with 10,000 more rows, and 2 more variables: ts_diameter <dbl>,
#> #   hu_diameter <dbl>

# grouped output
memdb_frame(storms) %>% group_by(status) %>% group_by()
#> # Source:   lazy query [?? x 13]
#> # Database: sqlite 3.34.1 [:memory:]
#> # Groups:   status
#>    name   year month   day  hour   lat  long status      category  wind pressure
#>    <chr> <dbl> <dbl> <int> <dbl> <dbl> <dbl> <chr>       <chr>    <int>    <int>
#>  1 Amy    1975     6    27     0  27.5 -79   tropical d… -1          25     1013
#>  2 Amy    1975     6    27     6  28.5 -79   tropical d… -1          25     1013
#>  3 Amy    1975     6    27    12  29.5 -79   tropical d… -1          25     1013
#>  4 Amy    1975     6    27    18  30.5 -79   tropical d… -1          25     1013
#>  5 Amy    1975     6    28     0  31.5 -78.8 tropical d… -1          25     1012
#>  6 Amy    1975     6    28     6  32.4 -78.7 tropical d… -1          25     1012
#>  7 Amy    1975     6    28    12  33.3 -78   tropical d… -1          25     1011
#>  8 Amy    1975     6    28    18  34   -77   tropical d… -1          30     1006
#>  9 Amy    1975     6    29     0  34.4 -75.8 tropical s… 0           35     1004
#> 10 Amy    1975     6    29     6  34   -74.8 tropical s… 0           40     1002
#> # … with more rows, and 2 more variables: ts_diameter <dbl>, hu_diameter <dbl>

^{Created on 2021-03-11 by the reprex package (v1.0.0)}