Fake throws when handled exceptions happen within a task.

[matthid]

Given the following FAKE-Script

open Fake
Target "Test" (fun _ ->
  try
    [ "test.dll" ]
      |> NUnit (fun _ -> failwith "test")
  with
  | exn ->
    ()
)

RunTargetOrDefault "Test"

Results in:

$ ./packages/FAKE/tools/FAKE.exe src/testScript.fsx
Building project with version: LocalBuild
Shortened DependencyGraph for Target Test:
<== Test

The resulting target order is:
 - Test
Starting Target: Test
Finished Target: Test
Running build failed.
Error:
System.Exception: Invalid tag structure. Trying to close target tag but stack is [task; target]
   at Fake.TraceHelper.closeTag@123.Invoke(String message) in C:\code\fake\src\app\FakeLib\TraceHelper.fs:line 123
   at Fake.TraceHelper.closeTag(String tag) in C:\code\fake\src\app\FakeLib\TraceHelper.fs:line 123
   at Fake.TraceHelper.traceEndTarget(String name) in C:\code\fake\src\app\FakeLib\TraceHelper.fs:line 139
   at Fake.TargetHelper.runSingleTarget(TargetTemplate`1 target) in C:\code\fake\src\app\FakeLib\TargetHelper.fs:line 485

---------------------------------------------------------------------
Build Time Report
---------------------------------------------------------------------
Target     Duration
------     --------
Test       00:00:00.1317542
Total:     00:00:00.1722803
Status:    Failure
---------------------------------------------------------------------
  1) System.Exception: Invalid tag structure. Trying to close target tag but stack is [task; target]
   at Fake.TraceHelper.closeTag@123.Invoke(String message) in C:\code\fake\src\app\FakeLib\TraceHelper.fs:line 123
   at Fake.TraceHelper.closeTag(String tag) in C:\code\fake\src\app\FakeLib\TraceHelper.fs:line 123
   at Fake.TraceHelper.traceEndTarget(String name) in C:\code\fake\src\app\FakeLib\TraceHelper.fs:line 139
   at Fake.TargetHelper.runSingleTarget(TargetTemplate`1 target) in C:\code\fake\src\app\FakeLib\TargetHelper.fs:line 485
---------------------------------------------------------------------

I don't thought this is expected behaviour, so I wanted to go ahaid and fix it. I noticed that the problem is that traceEndTask is not properly in finally blocks. However, as the change is quite invasive, I wanted to ask here first: Should they be in a finally block or is this by-design?

[pushasha]

I'm having the same issue when running my tests. After all the tests are run, FAKE throws the InvalidTagStructure exception mentioned above when there are failures, even if the failure-related exception is caught. This is problematic, as the "invalid tag structure", not the failing unit tests, is what shows up as the reason for build failure on our CI tools.

[matthid]

btw my current workaround is to call the missing traceEndTask manually, which is obviously nasty (and will break again when the bug is fixed)

[pushasha]

@matthid Thank you for the workaround! Even though it's "nasty", it definitely helps -- It'll keep people from telling me my scripts are "broken" when their unit tests fail and they see a FAKE exception rather than the actual test failure.

[TangoMikeOscar]

I am getting this issue also when trying to catch errors from a nuget publish. Please fix!

@matthid Could you post your traceEndTask fix so I can see what it looks like and how it would fit into my flow? Thanks

[matthid]

@stevephillips

Please fix!

Usually the best way to get it fixed is to send a Pull-Request ;)

The following works for me:

try
  files
    |> NUnit (fun p -> raise <| MyError ("T."))
  true
with
| MyError s ->
  traceEndTask "NUnit" (files |> separated ", ") // Workaround for https://github.com/fsharp/FAKE/issues/1079
  false

[dsyme]

Fixed by @0x53A - great!