Weird error message when there where two targets with the same name

[wallymathieu]

Description

While writing a FAKE script I got a rather weird error message when there where two targets with the same name.

Repro steps

How did I get it wrong? Well I wrote the following:

Target "test" (fun _ -> // supposed to have been tests_only
    !! testAssemblies
    |> NUnit (fun p ->
        { p with
            DisableShadowCopy = true
            TimeOut = TimeSpan.FromMinutes 20.
            OutputFile = "TestResults.xml" })
)

Target "test" (fun _ -> ())

Expected behavior

I would have expected FAKE to report that target was already declared or something along those lines.

Actual behavior

This is the output I got:

No version specified. Downloading latest stable.
Paket.exe 3.19.3.0 is up to date.
Paket version 3.19.3.0
0 seconds - ready.
FsiEvaluationException:

Error: System.ArgumentException: An item with the same key has already been added.
      at System.ThrowHelper.ThrowArgumentException (System.ExceptionResource resource) [0x0000b] in <94fd79a3b7144c54b4cb162b50fc7761>:0 
      at System.Collections.Generic.Dictionary`2[TKey,TValue].Insert (TKey key, TValue value, System.Boolean add) [0x0008e] in <94fd79a3b7144c54b4cb162b50fc7761>:0 
      at System.Collections.Generic.Dictionary`2[TKey,TValue].Add (TKey key, TValue value) [0x00000] in <94fd79a3b7144c54b4cb162b50fc7761>:0 
      at Fake.TargetHelper.targetFromTemplate[a] (Fake.TargetHelper+TargetTemplate`1[a] template, System.String name, a parameters) [0x00024] in <57cd19dfccf1c534a7450383df19cd57>:0 
      at Fake.TargetHelper.TargetTemplateWithDependencies[a] (Microsoft.FSharp.Collections.FSharpList`1[T] dependencies, Microsoft.FSharp.Core.FSharpFunc`2[T,TResult] body, System.String name, a parameters) [0x00017] in <57cd19dfccf1c534a7450383df19cd57>:0 
      at Fake.TargetHelper+TargetTemplate@254[a].Invoke (System.String name, a parameters) [0x00001] in <57cd19dfccf1c534a7450383df19cd57>:0 
      at Microsoft.FSharp.Core.FSharpFunc`2[T,TResult].InvokeFast[V] (Microsoft.FSharp.Core.FSharpFunc`2[T,TResult] func, T arg1, TResult arg2) [0x0000d] in <5584aad2904cf4daa7450383d2aa8455>:0 
      at <StartupCode$FSI_0005>.$FSI_0005_Build$fsx.main@ () [0x00091] in <760ff6be6b094913941f6a830312d643>:0 
      at (wrapper managed-to-native) System.Reflection.MonoMethod:InternalInvoke (System.Reflection.MonoMethod,object,object[],System.Exception&)
      at System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00038] in <94fd79a3b7144c54b4cb162b50fc7761>:0 
    Stopped due to error


Output: [Loading /Users/mathieu/src/LogAdapter/build.fsx]


Input: /Users/mathieu/src/LogAdapter/build.fsx

Exception: Yaaf.FSharp.Scripting.FsiEvaluationException: Error while compiling or executing fsharp snippet. ---> System.Exception: Operation failed. The error text has been print the error stream. To return the corresponding FSharpErrorInfo use the EvalInteractionNonThrowing, EvalScriptNonThrowing or EvalExpressionNonThrowing
  at Microsoft.FSharp.Compiler.Interactive.Shell+FsiEvaluationSession.commitResult[a,b] (Microsoft.FSharp.Core.FSharpChoice`2[T1,T2] res) [0x00030] in <5707a2f5ddab8ea7a7450383f5a20757>:0 
  at Microsoft.FSharp.Compiler.Interactive.Shell+FsiEvaluationSession.EvalScript (System.String filePath) [0x00014] in <5707a2f5ddab8ea7a7450383f5a20757>:0 
  at Yaaf.FSharp.Scripting.Helper+evalScript@1097.Invoke (System.String arg00) [0x00001] in <57cd19dfccf1c534a7450383df19cd57>:0 
  at Yaaf.FSharp.Scripting.Helper+saveScript@1090-1[a].Invoke (System.String path) [0x00033] in <57cd19dfccf1c534a7450383df19cd57>:0 
  at Yaaf.FSharp.Scripting.Helper+save_@1072-2[a].Invoke (Microsoft.FSharp.Core.Unit unitVar0) [0x00001] in <57cd19dfccf1c534a7450383df19cd57>:0 
  at Yaaf.FSharp.Scripting.Helper.consoleCapture[a] (System.IO.TextWriter out, System.IO.TextWriter err, Microsoft.FSharp.Core.FSharpFunc`2[T,TResult] f) [0x0001a] in <57cd19dfccf1c534a7450383df19cd57>:0 
  at Yaaf.FSharp.Scripting.Helper.redirectOut@1044[a] (System.Boolean preventStdOut, Yaaf.FSharp.Scripting.Helper+OutStreamHelper out, Yaaf.FSharp.Scripting.Helper+OutStreamHelper err, Microsoft.FSharp.Core.FSharpFunc`2[T,TResult] f) [0x0006e] in <57cd19dfccf1c534a7450383df19cd57>:0 
  at Yaaf.FSharp.Scripting.Helper+save_@1071-1[a].Invoke (System.String text) [0x0002c] in <57cd19dfccf1c534a7450383df19cd57>:0 
   --- End of inner exception stack trace ---
  at Yaaf.FSharp.Scripting.Helper+save_@1071-1[a].Invoke (System.String text) [0x0008e] in <57cd19dfccf1c534a7450383df19cd57>:0 
  at Yaaf.FSharp.Scripting.Helper+session@1100.Yaaf-FSharp-Scripting-IFsiSession-EvalScriptWithOutput (System.String ) [0x00001] in <57cd19dfccf1c534a7450383df19cd57>:0 
  at Fake.FSIHelper.runScriptUncached (System.Boolean useCache, System.String scriptPath, System.Collections.Generic.IEnumerable`1[T] fsiOptions, System.Boolean printDetails, Fake.FSIHelper+CacheInfo cacheInfo, System.IO.TextWriter out, System.IO.TextWriter err) [0x00187] in <57cd19dfccf1c534a7450383df19cd57>:0 
System.ArgumentException: An item with the same key has already been added.
  at System.ThrowHelper.ThrowArgumentException (System.ExceptionResource resource) [0x0000b] in <94fd79a3b7144c54b4cb162b50fc7761>:0 
  at System.Collections.Generic.Dictionary`2[TKey,TValue].Insert (TKey key, TValue value, System.Boolean add) [0x0008e] in <94fd79a3b7144c54b4cb162b50fc7761>:0 
  at System.Collections.Generic.Dictionary`2[TKey,TValue].Add (TKey key, TValue value) [0x00000] in <94fd79a3b7144c54b4cb162b50fc7761>:0 
  at Fake.TargetHelper.targetFromTemplate[a] (Fake.TargetHelper+TargetTemplate`1[a] template, System.String name, a parameters) [0x00024] in <57cd19dfccf1c534a7450383df19cd57>:0 
  at Fake.TargetHelper.TargetTemplateWithDependencies[a] (Microsoft.FSharp.Collections.FSharpList`1[T] dependencies, Microsoft.FSharp.Core.FSharpFunc`2[T,TResult] body, System.String name, a parameters) [0x00017] in <57cd19dfccf1c534a7450383df19cd57>:0 
  at Fake.TargetHelper+TargetTemplate@254[a].Invoke (System.String name, a parameters) [0x00001] in <57cd19dfccf1c534a7450383df19cd57>:0 
  at Microsoft.FSharp.Core.FSharpFunc`2[T,TResult].InvokeFast[V] (Microsoft.FSharp.Core.FSharpFunc`2[T,TResult] func, T arg1, TResult arg2) [0x0000d] in <5584aad2904cf4daa7450383d2aa8455>:0 
  at <StartupCode$FSI_0005>.$FSI_0005_Build$fsx.main@ () [0x00091] in <760ff6be6b094913941f6a830312d643>:0 
  at (wrapper managed-to-native) System.Reflection.MonoMethod:InternalInvoke (System.Reflection.MonoMethod,object,object[],System.Exception&)
  at System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00038] in <94fd79a3b7144c54b4cb162b50fc7761>:0 
Stopped due to error

Related information

• Operating system : OS X El Capitan
• .NET Runtime: mono-4.6.0-branch/dea2155 Wed Sep 7 10:34:49 EDT 2016

[embix]

I second that. Just got the same error when we had the same target added in different branches. While the merge went fine without conflicts, the build (of course failed). Explicitly naming the task should make debugging such cases easier.

[forki]

Please send a fix. It's probably a dictionary add call failing somewhere. Am 27.03.2017 20:01 schrieb "Michel Bretschneider" <notifications@github.com

…

: I second that. Just got the same error when we had the same target added in different branches. While the merge went fine without conflicts, the build (of course failed). Explicitly naming the task should make debugging such cases easier. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#1375 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AADgNAqWsQqk-Af6I5YOJmNs3CJP1xLOks5rp8xcgaJpZM4J6QPC> .

[embix]

Bread and butter solution: just throw an exception and provide the name of the duplicate target. If there is a more sophisticated way of croaking in FAKE just give me a hint.