From ffe5e4f2cf017bdccd0a3c8b9cebee7b02096d8d Mon Sep 17 00:00:00 2001
From: Matthias Dittrich <matthi.d@gmail.com>
Date: Thu, 10 May 2018 15:38:00 +0200
Subject: [PATCH] Improve exception message and handling of DocoptException

Fix https://github.com/MangelMaxime/fulma-demo/issues/4
Fix https://github.com/fsharp/FAKE/issues/1916
---
 .../docopt.fs/Docopt/UsageParser.fs           |  2 +-
 src/app/Fake.Core.Target/Target.fs            |  2 +-
 src/app/Fake.netcore/Program.fs               | 28 ++++++++++---------
 3 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/src/app/Fake.Core.CommandLineParsing/docopt.fs/Docopt/UsageParser.fs b/src/app/Fake.Core.CommandLineParsing/docopt.fs/Docopt/UsageParser.fs
index 623bc73a676..e2ddfd4bdcf 100644
--- a/src/app/Fake.Core.CommandLineParsing/docopt.fs/Docopt/UsageParser.fs
+++ b/src/app/Fake.Core.CommandLineParsing/docopt.fs/Docopt/UsageParser.fs
@@ -1,7 +1,7 @@
 namespace Fake.Core
 
 exception DocoptException of string
-  with override x.ToString () = sprintf "DocoptException: %s" x.Data0
+  with override x.Message = sprintf "DocoptException: %s" x.Data0
 
 namespace Fake.Core.CommandLineParsing
 
diff --git a/src/app/Fake.Core.Target/Target.fs b/src/app/Fake.Core.Target/Target.fs
index 440f7ce2065..988e8eb23f9 100644
--- a/src/app/Fake.Core.Target/Target.fs
+++ b/src/app/Fake.Core.Target/Target.fs
@@ -649,7 +649,7 @@ module Target =
                 | None -> fDefault singleTarget parallelJobs arguments
         | Choice2Of2 e ->
             // To ensure exit code.
-            failwithf "Usage error: %s\n%s" e.Message TargetCli.targetCli
+            raise <| exn (sprintf "Usage error: %s\n%s" e.Message TargetCli.targetCli, e)
 
     /// Runs the command given on the command line or the given target when no target is given
     let runOrDefault defaultTarget =
diff --git a/src/app/Fake.netcore/Program.fs b/src/app/Fake.netcore/Program.fs
index fd8c3f66cd2..1e5c19c5dfc 100644
--- a/src/app/Fake.netcore/Program.fs
+++ b/src/app/Fake.netcore/Program.fs
@@ -78,6 +78,18 @@ type RunArguments = {
    IsBuild : bool // Did the user call `fake build` or `fake run`?
 }
 
+let reportExn (verb:VerboseLevel) exn =
+  use logPaket =
+    // Required when 'silent' because we use paket API for error printing
+    if verb = Trace.Silent then
+      Paket.Logging.event.Publish
+      |> Observable.subscribe Paket.Logging.traceToConsole
+    else { new IDisposable with member __.Dispose () = () }      
+  traceError "Script failed"
+  if Environment.GetEnvironmentVariable "FAKE_DETAILED_ERRORS" = "true" then
+      Paket.Logging.printErrorExt true true true exn
+  else Paket.Logging.printErrorExt verb.PrintVerbose verb.PrintVerbose false exn
+
 let runOrBuild (args : RunArguments) =
   if args.VerboseLevel.PrintVerbose then
     Trace.log (sprintf "runOrBuild (%A)" args)
@@ -147,17 +159,7 @@ let runOrBuild (args : RunArguments) =
         Fake.Profile.print true sw.Elapsed
   with
   | exn ->
-      use logPaket =
-        // Required when 'silent' because we use paket API for error printing
-        if args.VerboseLevel = Trace.Silent then
-          Paket.Logging.event.Publish
-          |> Observable.subscribe Paket.Logging.traceToConsole
-        else { new IDisposable with member __.Dispose () = () }      
-      traceError "Script failed"
-      if Environment.GetEnvironmentVariable "FAKE_DETAILED_ERRORS" = "true" then
-          Paket.Logging.printErrorExt true true true exn
-      else Paket.Logging.printErrorExt args.VerboseLevel.PrintVerbose args.VerboseLevel.PrintVerbose false exn
-
+      reportExn args.VerboseLevel exn
       //let isKnownException = exn :? FAKEException
       //if not isKnownException then
       //    sendTeamCityError exn.Message
@@ -294,9 +296,9 @@ let main (args:string[]) =
       parseAction rawResults
     exitCode <- handleAction verbLevel results
   with
-  | :? DocoptException as e ->
-    printfn "Usage error: %s" e.Message
+  | exn ->
     printfn "%s" Cli.fakeUsage
+    reportExn VerboseLevel.Normal exn
     exitCode <- 1
   Console.OutputEncoding <- encoding
 #if !NETSTANDARD1_6