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Example with Option with IEnumerable<string> broken - Sequence contains more than one element #377

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ivberg-zz opened this issue Dec 7, 2018 · 5 comments
Open

Example with Option with IEnumerable<string> broken - Sequence contains more than one element #377

ivberg-zz opened this issue Dec 7, 2018 · 5 comments
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@ivberg-zz
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@ivberg-zz ivberg-zz commented Dec 7, 2018

Running the latest commandlineparser v2.3.0 on .Net Core 2.1.

The library example doesn't seem to work at all parsing IEnumerable
[Option('r', "read", Required = true, HelpText = "Input files to be processed.")]
public IEnumerable InputFiles { get; set; }

If you specify --read file1 file2 you get this exception:

System.InvalidOperationException
HResult=0x80131509
Message=Sequence contains more than one element
Source=System.Linq
StackTrace:

System.Linq.dll!System.Linq.Enumerable.Single<System.Type>(System.Collections.Generic.IEnumerable<System.Type> source) Line 45 C#
CommandLine.dll!CommandLine.Core.InstanceBuilder.Build.AnonymousMethod__0_23(CommandLine.Core.SpecificationProperty sp) Unknown
CommandLine.dll!CommandLine.Core.ReflectionExtensions.SetProperties.AnonymousMethod__0(System.__Canon current, CommandLine.Core.SpecificationProperty specProp) Unknown
System.Linq.dll!System.Linq.Enumerable.Aggregate<CommandLine.Core.SpecificationProperty, LogMerger.Program.Options>(System.Collections.Generic.IEnumerable<CommandLine.Core.SpecificationProperty> source, LogMerger.Program.Options seed, System.Func<LogMerger.Program.Options, CommandLine.Core.SpecificationProperty, LogMerger.Program.Options> func) Line 55 C#
CommandLine.dll!CommandLine.Core.InstanceBuilder.Build.AnonymousMethod__16() Unknown
CommandLine.dll!CommandLine.Core.InstanceBuilder.Build.AnonymousMethod__7() Unknown
CommandLine.dll!CommandLine.Parser.ParseArguments<LogMerger.Program.Options>(System.Collections.Generic.IEnumerable args) Unknown
@ivberg-zz
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@ivberg-zz ivberg-zz commented Dec 7, 2018

Actually, this was an issue instead with Parsing a Dict
public Dictionary<string, string> Dict { get; set; }

Is this supported?
@nemec
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@nemec nemec commented Dec 7, 2018

No, unfortunately dicts are not supported
@ericnewton76
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@ericnewton76 ericnewton76 commented Dec 12, 2018

A dictionary would be hard to support... what generates the keys for the values?

I would believe this is undefined in the getopt specs that this library strives to follow.
@ivberg-zz
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@ivberg-zz ivberg-zz commented Dec 12, 2018

I think you are correct Eric that it would be hard to support. I think this is more about protecting against dumb new user and a clearer exception behavior than implementing support :). As a C# dev, Dictionary is popular and for better or worse, it's what I expected/hoped to use here as one of the cmd line options. The above is actually misleading, as I thought the IEnumerable is what was causing the issue, but instead the Dict used as another possible cmd-line parameter (turns out didn't need it)

My suggestion is the user adds odd or not supported stuff, that we have a clearer exception than
System.InvalidOperationException - Message=Sequence contains more than one element
@ericnewton76
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@ericnewton76 ericnewton76 commented Jan 23, 2019

Indeed. The error is misleading.
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@nemec @ericnewton76 @ivberg-zz
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