tryparse Inexact Error

[Arkoniak]

It seems that this commit: b82a753 introduced regression in processing of tryparse function in function pqparse(::Type{DateTime}, str::AbstractString), similar to the issue that was resolved in #248

So, currently in some 1.6 and 1.7 versions of Julia, selecting from the postgres table which has timestamp column results in InexactError from tryparse function.

[iamed2]

Can you give an example please?

I cannot seem to replicate this on Julia 1.6.7 with LibPQ 1.15.1.

[Arkoniak]

Sure.

Julia 1.7.1, LibPQ 1.15.1:

using LibPQ
using Dates

LibPQ.pqparse(DateTime, "2023-03-03 12:34:56.789012")

yields output

ERROR: InexactError: convert(Dates.Decimal3, 789012)
Stacktrace:
 [1] tryparsenext
   @ ~/Languages/julia-1.7.1/share/julia/stdlib/v1.7/Dates/src/io.jl:153 [inlined]
 [2] tryparsenext
   @ ~/Languages/julia-1.7.1/share/julia/stdlib/v1.7/Dates/src/io.jl:41 [inlined]
 [3] macro expansion
   @ ~/Languages/julia-1.7.1/share/julia/stdlib/v1.7/Dates/src/parse.jl:64 [inlined]
 [4] tryparsenext_core(str::String, pos::Int64, len::Int64, df::DateFormat{Symbol("y-m-d HH:MM:SS.s"), Tuple{Dates.DatePart{'y'}, Dates.Delim{Char, 1}, Dates.DatePart{'m'}, Dates.Delim{Char, 1}, Dates.DatePart{'d'}, Dates.Delim{Char, 1}, Dates.DatePart{'H'}, Dates.Delim{Char, 1}, Dates.DatePart{'M'}, Dates.Delim{Char, 1}, Dates.DatePart{'S'}, Dates.Delim{Char, 1}, Dates.DatePart{'s'}}}, raise::Bool)
   @ Dates ~/Languages/julia-1.7.1/share/julia/stdlib/v1.7/Dates/src/parse.jl:38
 [5] macro expansion
   @ ~/Languages/julia-1.7.1/share/julia/stdlib/v1.7/Dates/src/parse.jl:150 [inlined]
 [6] tryparsenext_internal
   @ ~/Languages/julia-1.7.1/share/julia/stdlib/v1.7/Dates/src/parse.jl:125 [inlined]
 [7] tryparse(::Type{DateTime}, str::String, df::DateFormat{Symbol("y-m-d HH:MM:SS.s"), Tuple{Dates.DatePart{'y'}, Dates.Delim{Char, 1}, Dates.DatePart{'m'}, Dates.Delim{Char, 1}, Dates.DatePart{'d'}, Dates.Delim{Char, 1}, Dates.DatePart{'H'}, Dates.Delim{Char, 1}, Dates.DatePart{'M'}, Dates.Delim{Char, 1}, Dates.DatePart{'S'}, Dates.Delim{Char, 1}, Dates.DatePart{'s'}}})
   @ Dates ~/Languages/julia-1.7.1/share/julia/stdlib/v1.7/Dates/src/parse.jl:290
 [8] pqparse(#unused#::Type{DateTime}, str::String)
   @ LibPQ ~/.julia/packages/LibPQ/gYEIG/src/parsing.jl:262
 [9] top-level scope
   @ REPL[8]:1

In Julia 1.8.2, LibPQ 1.15.1

using LibPQ
using Dates

LibPQ.pqparse(DateTime, "2023-03-03 12:34:56.789012")

yields

2023-03-03T12:34:56.789

Also, Julia 1.7.1, LibPQ 1.14.1

julia> using LibPQ
julia> using Dates
julia> LibPQ.pqparse(DateTime, "2023-03-03 12:34:56.789123")
2023-03-03T12:34:56.789

[iamed2]

This works properly with LibPQ.jl 1.15.1 on Julia 1.7.3, Julia 1.6.7, and Julia 1.8.2+. Unfortunately my suggestion is to upgrade Julia to a later patch version, since the above error is a bug in Julia that was fixed.

[Arkoniak]

Sorry, I do not quite understand...
Why can't we do the same as in #248? It seems simple enough.

Or, even better, just change https://github.com/iamed2/LibPQ.jl/blob/master/src/parsing.jl#L262 from

parsed = tryparse(DateTime, str, TIMESTAMP_FORMAT)

to

parsed = tryparse(DateTime, _trunc_seconds(str), TIMESTAMP_FORMAT)

as it basically was in 1.14.1?

I can make a PR if you do not have time for these changes, no big deal.

[iamed2]

I would accept a PR for a static version-guarded fix for old patch versions. Typically, old patch versions of Julia are not supported, as they are neither tested in CI nor recommended for installation by the Julia developers. And I do not want to impact performance for everyone by adding regex replacement to every parse call (which is why it is written as it is now). But a different version guarded by @static would have no performance impact and is clearly marked.

I cannot guarantee it will survive in perpetuity, especially if there is a refactor. Testing on old patch versions is wasteful. However, if you reference this issue, I will ping you before removing your changes in the future to check if you've moved to a patched version of Julia.