read_tsv() doesn't un-escape doubled quotes

[lazappi]

When you use read_tsv() to read a file which contains quotes escaped by doubling (which is the default in write_tsv()) instead of the quotes being un-escaped you get strings with two quotes. If a file goes through multiple read/write cycles you end up with increasingly large sequences of quotes.

df1 <- tibble::tribble(
    ~ A, ~ B,
    "String", 1,
    "String with 'single quotes'", 2,
    'String with "double quotes"', 3
)

readr::write_tsv(df1, "file1.tsv")
df2 <- readr::read_tsv("file1.tsv", col_types = "cd")

waldo::compare(df1, df2)
#> old vs new
#>                                        A
#>   old[1, ] String                       
#>   old[2, ] String with 'single quotes'  
#> - old[3, ] String with "double quotes"  
#> + new[3, ] String with ""double quotes""
#> 
#>     old$A                           | new$A                                  
#> [1] "String"                        | "String"                            [1]
#> [2] "String with 'single quotes'"   | "String with 'single quotes'"       [2]
#> [3] "String with \"double quotes\"" - "String with \"\"double quotes\"\"" [3]

readr::write_tsv(df2, "file2.tsv")
df3 <- readr::read_tsv("file2.tsv", col_types = "cd")

waldo::compare(df1, df3)
#> old vs new
#>                                            A
#>   old[1, ] String                           
#>   old[2, ] String with 'single quotes'      
#> - old[3, ] String with "double quotes"      
#> + new[3, ] String with """"double quotes""""
#> 
#> old$A vs new$A
#>   "String"
#>   "String with 'single quotes'"
#> - "String with \"double quotes\""
#> + "String with \"\"\"\"double quotes\"\"\"\""

^{Created on 2022-05-06 by the reprex package (v2.0.1)}

Session info

sessioninfo::session_info()
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#>  tz       Europe/Berlin
#>  date     2022-05-06
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#> 
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#> ──────────────────────────────────────────────────────────────────────────────

You can avoid this by setting escape in write_tsv() but would it make sense to have a similar argument for read_tsv() that does this in reverse?

[hadley]

Something is weird is going on here:

library(readr)

path <- tempfile()
write_tsv(data.frame(x = c('-"a"-', '"b"')), path)
writeLines(read_lines(path))
#> x
#> -""a""-
#> ""b""

cat(read_tsv(path, col_types = list())$x)
#> -""a""- b"
cat(read_delim(path, col_types = list(), quote = "", delim = ",", escape_double = TRUE)$x)
#> -""a""- ""b""

^{Created on 2023-07-31 with reprex v2.0.2}

I can't seem to get this to read in even when I set all the options that I think should make it work. And look at what happens to b — it gets a quote on one side.