`sprintf "%b" bool` causes AOT failure

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`sprintf "%b" bool` causes AOT failure #17691

Open Smaug123 opened 1 month ago

Smaug123 commented 1 month ago

sprintf "%b" true does not work in AOT context; nor does sprintf "%O" true. This affects linux-x64 8.0.401 and v9 preview 1, but not osx-arm64 8.0.300, in my testing.

Repro steps

In an executable with <PublishAot>true</PublishAot>:

let s = sprintf "%O" true // or "%b"
System.Console.WriteLine s

Expected behavior

Program prints "true".

Actual behavior

System.NotSupportedException: 'Microsoft.FSharp.Core.PrintfImpl+Specializations`3[Microsoft.FSharp.Core.Unit,System.String,System.String].CaptureFinal1[System.Boolean](Microsoft.FSharp.Core.PrintfImpl+Step[])' is missing native code.

Known workarounds

(fun s -> $"%O{s}") true works, as does x.ToString () |> sprintf "%s".

Related information

Reproduced on linux-x64 with net8.0.401 and net9 preview 7, but not osx-arm64 8.0.300.

charlesroddie commented 2 weeks ago

Do you have need for sprintf in preference to interpolated strings? It would be better to focus effort on improving interpolated strings (by making them work via a string collector) than working on sprintf which is generally unsalvageable.

Smaug123 commented 2 weeks ago

Yeah, I write source generators and am not really willing to break compatibility for my (completely uncontrolled) consumers. I could of course parameterise the generators or do some work to make available to them the current version of F#, or more practically I could just accept that there are bugs and manually call ToString on everything; that's certainly not the end of the world.

charlesroddie commented 1 week ago

F# 5.0 with string interpolation was released 2020. Can't imagine why anyone would be using previous versions at this point.

Anyway the options are:

sprintf: bad performance, AOT-incompatible, medium readability.
interpolated strings: bad performance, AOT-compatible, high readability. Planned to be made good performance in future with string collectors (and then should be better for AOT app size since the current implementation has bloat from complex intermediate types).
manually calling ToString and concatenating the results: good performance, AOT compatible, low readability.

majocha commented 1 week ago

F# 5.0 with string interpolation was released 2020. Can't imagine why anyone would be using previous versions at this point.

Partial application is one thing you can't do with interpolated formatting.