add some logic to write relative instead of absolute paths to cache, f…

…ixes #1924

src/app/Fake.Runtime/CoreCache.fs

@@ -323,7 +323,7 @@ let prepareContext (config:FakeConfig) (cache:ICachingProvider) =
         |> Seq.map File.ReadAllText
         |> fun texts -> File.WriteAllText(fakeCacheContentsFile, String.Join("", texts))
         // write fakeCacheDepsFile
-        File.WriteAllLines(fakeCacheDepsFile, locations)
+        File.WriteAllLines(fakeCacheDepsFile, locations |> Seq.map (Path.fixPathForCache config.ScriptFilePath))
 
     let readFromCache () =
         File.ReadAllText fakeCacheFile
@@ -340,6 +340,7 @@ let prepareContext (config:FakeConfig) (cache:ICachingProvider) =
         let inline dependencyCacheUpdated () =
             let contents =
                 File.ReadLines fakeCacheDepsFile
+                |> Seq.map (Path.readPathFromCache config.ScriptFilePath)
                 |> Seq.map (fun line -> if File.Exists line then Some (File.ReadAllText line) else None)
                 |> Seq.toList
             if contents |> Seq.exists Option.isNone then false

src/app/Fake.Runtime/Environment.fs

@@ -55,3 +55,4 @@ let environVarOrNone name =
 
 /// Returns if the build parameter with the given name was set
 let inline hasEnvironVar name = environVar name |> isNull |> not
+

src/app/Fake.Runtime/FakeRuntime.fs

@@ -5,6 +5,7 @@ open System.IO
 open Fake.Runtime
 open Fake.Runtime.Runners
 open Paket
+open System
 
 type FakeSection =
  | PaketDependencies of Paket.Dependencies * Lazy<Paket.DependenciesFile> * group : String option
@@ -385,7 +386,7 @@ let paketCachingProvider (config:FakeConfig) cacheDir (paketApi:Paket.Dependenci
         let splits = line.Split(';')
         let isRef = bool.Parse splits.[0]
         let ver = splits.[1]
-        let loc = splits.[2]
+        let loc = Path.readPathFromCache config.ScriptFilePath splits.[2]
         let fullName = splits.[3]
         { IsReferenceAssembly = isRef
           Info =
@@ -395,12 +396,12 @@ let paketCachingProvider (config:FakeConfig) cacheDir (paketApi:Paket.Dependenci
       |> Seq.toList
 
   let writeToCache (list:AssemblyData list) =
-      list 
+      list
       |> Seq.map (fun item -> 
         sprintf "%b;%s;%s;%s" 
             item.IsReferenceAssembly
             item.Info.Version
-            item.Info.Location
+            (Path.fixPathForCache config.ScriptFilePath item.Info.Location)
             item.Info.FullName)
       |> fun lines -> File.WriteAllLines(assemblyCacheFile, lines)
       File.Copy(lockFilePath.FullName, assemblyCacheHashFile, true)
@@ -521,7 +522,7 @@ let prepareFakeScript (config:FakeConfig) =
     let writeToCache (section : FakeSection option) =
         match section with 
         | Some (PaketDependencies(p, _, group)) ->
-            sprintf "paket: %s, %s" p.DependenciesFile (match group with | Some g -> g | _ -> "<null>")
+            sprintf "paket: %s, %s" (Path.fixPathForCache config.ScriptFilePath p.DependenciesFile) (match group with | Some g -> g | _ -> "<null>")
         | None -> "none"
         |> fun t -> File.WriteAllText(scriptSectionCacheFile, t)
         File.Copy (script, scriptSectionHashFile, true)
@@ -531,7 +532,7 @@ let prepareFakeScript (config:FakeConfig) =
         if t.StartsWith("paket:") then 
             let s = t.Substring("paket: ".Length)
             let splits = s.Split(',')
-            let depsFile = splits.[0]
+            let depsFile = Path.readPathFromCache config.ScriptFilePath splits.[0]
             let group =
                 let trimmed = splits.[1].Trim()
                 if trimmed = "<null>" then None else Some trimmed
@@ -626,4 +627,4 @@ let retrieveHints (config:FakeConfig) (runResult:Runners.RunResult) =
           yield "To further diagnose the problem you can set the 'FAKE_DETAILED_ERRORS' environment variable to 'true'"
         if not config.VerboseLevel.PrintVerbose && Environment.GetEnvironmentVariable "FAKE_DETAILED_ERRORS" <> "true" then
           yield "To further diagnose the problem you can run fake in verbose mode `fake -v run ...` or set the 'FAKE_DETAILED_ERRORS' environment variable to 'true'"
-      ]
+      ]

src/app/Fake.Runtime/Path.fs

@@ -1,11 +1,36 @@
 /// Contains basic functions for string manipulation.
 
 module Fake.Runtime.Path
+open System
 open System.IO
 
 // Normalizes path for different OS
 let inline normalizePath (path : string) = 
     path.Replace('\\', Path.DirectorySeparatorChar).Replace('/', Path.DirectorySeparatorChar)
 
 let getCurrentDirectory () =
-    System.IO.Directory.GetCurrentDirectory()
+    System.IO.Directory.GetCurrentDirectory()
+
+let private nugetDir = Path.GetFullPath(Paket.Constants.UserNuGetPackagesFolder).TrimEnd([|'/' ;'\\'|]) + "/"
+let fixPathForCache scriptPath (s:string) =
+    let norm = Path.GetFullPath s
+    if norm.StartsWith(nugetDir, if Paket.Utils.isWindows then StringComparison.OrdinalIgnoreCase else StringComparison.Ordinal) then
+      sprintf "nugetcache://%s" (norm.Substring (nugetDir.Length))
+    else
+      let scriptDir = Uri(Path.GetDirectoryName scriptPath + "/")
+      let other = Uri(s)
+      let rel = scriptDir.MakeRelativeUri(other)
+      if rel.IsAbsoluteUri then rel.AbsoluteUri
+      else
+        sprintf "scriptpath:///%s" rel.OriginalString
+
+let readPathFromCache scriptPath (s:string) =
+    let uri = Uri(s)
+    if uri.Scheme = "nugetcache" then
+        let rel = uri.AbsolutePath.TrimStart [| '/'|]
+        Path.Combine (nugetDir, rel)
+    elif uri.Scheme = "scriptpath" then
+        let rel = uri.OriginalString.Substring("scriptpath:///".Length)
+        Path.Combine(Path.GetDirectoryName scriptPath, rel)
+    else
+        uri.AbsolutePath