read_gtfs parsing failures detection

[ipeagit]

read_gtfs parsing failures detection

[dhersz]

Also, another problem is that fread seems not to do well with tryCatch. Check this:

gtfs <- read_gtfs("../msc-thesis/otp/graphs/rio/ola.zip")
#> Warning message:
#> In read_gtfs("../msc-thesis/otp/graphs/rio/ola.zip") :
#>   Parsing failures while reading the following file(s): trips, stops
gtfs <- read_gtfs("../msc-thesis/otp/graphs/rio/ola.zip")
#> Error in utils::unzip(path, files = files_to_read, exdir = temp_dir, overwrite = TRUE) : 
#>   não foi possível abrir o arquivo 'C:/Users/Usuario/AppData/Local/Temp/RtmpqS6Xww/gtfsdir/stops.txt': Invalid argument
gtfs <- read_gtfs("../msc-thesis/otp/graphs/rio/ola.zip", "stop_times")
gtfs <- read_gtfs("../msc-thesis/otp/graphs/rio/ola.zip")
#> Warning message:
#> In read_gtfs("../msc-thesis/otp/graphs/rio/ola.zip") :
#>   Parsing failures while reading the following file(s): trips, stops

I actually suppress a possible warning when reading the gtfs due to how the function is structured. If I remove these warning supression you can see that fread does some cleaning after the "invalid argument" error.

gtfs <- read_gtfs("../msc-thesis/otp/graphs/rio/ola.zip")
#> Error in utils::unzip(path, files = files_to_read, exdir = temp_dir, overwrite = TRUE) : 
#>   não foi possível abrir o arquivo 'C:/Users/Usuario/AppData/Local/Temp/RtmpqS6Xww/gtfsdir/stops.txt': Invalid argument
gtfs <- read_gtfs("../msc-thesis/otp/graphs/rio/ola.zip", "stop_times")
#> Warning message:
#> In data.table::fread(file.path(temp_dir, file), nrows = 1) :
#>   Previous fread() session was not cleaned up properly. Cleaned up ok at the beginning of this fread() call.

Related data.table issue: Rdatatable/data.table#2904

[dhersz]

313e2ce changes read_gtfs behaviour a bit. Parsing failures (actually, any warnings thrown by data.table::fread, let's see how that scales up) now result in errors, instead of warnings, and read_gtfs now consistently outputs a GTFS object, instead of eventual parsing failures messages.

I'll keep this issue open for a while still, let's see how this change ages.

[dhersz]

This whole parsing-failure-detection ensemble is gonna get fixed in {gtfsio}. Using withCallingHandlers() instead of tryCatch() does the trick.