[repo-assist] Allow sources to be specified as Environment Variables, with docs

docs/content/nuget-dependencies.md

@@ -56,6 +56,21 @@ The [`paket.lock` file](lock-file.html) will also reflect these settings.
 values are `basic` and `ntlm`. If no authentication type is specified, basic
 authentication will be used.
 
+It's also possible to specify the entire source line as an environment variable.
+This is useful if you don't want the feed URL (or its credentials) to appear in
+source control at all:
+
+```paket
+source %FEED_URL%
+```
+
+Here, the `FEED_URL` environment variable must contain everything that would
+normally follow the `source` keyword, for example:
+
+```
+http://myserver/nuget/api/v2 username: "%PRIVATE_FEED_USER%" password: "%PRIVATE_FEED_PASS%" authtype: "ntlm"
+```
+
 **Note:** If [`paket.dependencies` file](dependencies-file.html) exists while
 running the [`convert-from-nuget` command](paket-convert-from-nuget.html), the
 `PRIVATE_FEED_USER` and `PRIVATE_FEED_PASS` will *not* be expanded. Please see

src/Paket.Core/Versioning/PackageSources.fs

@@ -144,10 +144,14 @@ type PackageSource =
                     |> fun xs -> if xs.Length = 0 then afterSource.Length else Array.min xs
                 afterSource.Substring(0, stopIdx).Trim().Replace("\"","").TrimEnd([| '/' |])
 
-        let feed = normalizeFeedUrl source
-        PackageSource.Parse(feed, parseAuth(line, feed))
-
-    static member Parse(source,auth) =
+        match EnvironmentVariable.Create(source) with
+        | None ->
+            let feed = normalizeFeedUrl source
+            PackageSource.Parse(feed, parseAuth(line, feed))
+        | Some var ->
+            PackageSource.Parse ("source " + var.Value)
+
+    static member Parse(source, auth) =
         match tryParseWindowsStyleNetworkPath source with
         | Some path -> PackageSource.Parse(path)
         | _ ->

tests/Paket.Tests/DependenciesFile/ParserSpecs.fs

@@ -779,6 +779,43 @@ let ``should read config with password in env variable and auth type specified``
     cfg.Groups.[Constants.MainDependencyGroup].Sources.Head.Auth.Retrieve true
         |> shouldEqual (Some (Credentials{ Username = "user XYZ"; Password = "pw Love"; Type = NetUtils.AuthType.NTLM}))
 
+let configWithSourceInEnvVariable = """
+source %FEED_URL%
+nuget Rx-Main
+"""
+
+[<Test>]
+let ``should read config with source in env variable``() = 
+    Environment.SetEnvironmentVariable("FEED_URL", "http://www.nuget.org/api/v2", EnvironmentVariableTarget.Process)
+    let cfg = DependenciesFile.FromSource(configWithSourceInEnvVariable)
+
+    cfg.Groups.[Constants.MainDependencyGroup].Sources 
+    |> shouldEqual [ 
+        PackageSource.NuGetV2 { 
+            Url = "http://www.nuget.org/api/v2"
+            Authentication = AuthProvider.empty} ]
+
+
+let configWithSourceAndCredentialsInEnvVariable = """
+source %FEED_URL%
+nuget Rx-Main
+"""
+
+[<Test>]
+let ``should read config with source and credentials in env variable``() = 
+    Environment.SetEnvironmentVariable("FEED_USERNAME", "user XYZ", EnvironmentVariableTarget.Process)
+    Environment.SetEnvironmentVariable("FEED_PASSWORD", "pw Love", EnvironmentVariableTarget.Process)
+    Environment.SetEnvironmentVariable("FEED_URL", "http://www.nuget.org/api/v2 username: \"%FEED_USERNAME%\" password: \"%FEED_PASSWORD%\" authtype: \"nTlM\"", EnvironmentVariableTarget.Process)
+    let cfg = DependenciesFile.FromSource(configWithSourceAndCredentialsInEnvVariable)
+
+    cfg.Groups.[Constants.MainDependencyGroup].Sources 
+    |> shouldEqual [ 
+        PackageSource.NuGetV2 { 
+            Url = "http://www.nuget.org/api/v2"
+            Authentication = AuthProvider.empty} ]
+    cfg.Groups.[Constants.MainDependencyGroup].Sources.Head.Auth.Retrieve true
+        |> shouldEqual (Some (Credentials{ Username = "user XYZ"; Password = "pw Love"; Type = NetUtils.AuthType.NTLM}))
+
 let configWithExplicitVersions = """
 source "http://www.nuget.org/api/v2"