Allow the solver to find workspace packages in a monorepo (#1196)

Properly ignore nested workspaces - we were missing the case with a no-package-root-config

Author: f-f

src/Spago/Command/Fetch.purs

@@ -454,7 +454,10 @@ getTransitiveDeps workspacePackage = do
       RegistrySolverBuild extraPackages -> do
         plan <- getTransitiveDepsFromRegistry depsRanges extraPackages
         logDebug $ "Got a plan from the Solver: " <> printJson (Internal.Codec.packageMap Version.codec) plan
-        pure (map RegistryVersion plan)
+        pure $ plan # Map.mapMaybeWithKey \packageName version -> case Map.lookup packageName extraPackages of
+          Just p -> Just p
+          Nothing -> Just $ RegistryVersion version
+
       PackageSetBuild _info set -> getTransitiveDepsFromPackageSet set (Array.fromFoldable $ Map.keys depsRanges)
 
   where

test-fixtures/monorepo/local-packages-work-with-solver/app/spago.yaml

@@ -0,0 +1,7 @@
+package:
+  name: app
+  dependencies:
+    - console
+    - effect
+    - prelude
+    - lib

test-fixtures/monorepo/local-packages-work-with-solver/app/src/Main.purs

@@ -0,0 +1 @@
+module App.Main where

test-fixtures/monorepo/local-packages-work-with-solver/expected-stderr.txt

@@ -0,0 +1,13 @@
+Reading Spago workspace configuration...
+
+✅ Selecting 2 packages to build:
+    app
+    lib
+
+Downloading dependencies...
+Building...
+           Src   Lib   All
+Warnings     0     0     0
+Errors       0     0     0
+
+✅ Build succeeded.

test-fixtures/monorepo/local-packages-work-with-solver/lib/spago.yaml

@@ -0,0 +1,6 @@
+package:
+  name: lib
+  dependencies:
+    - console
+    - effect
+    - prelude

test-fixtures/monorepo/local-packages-work-with-solver/lib/src/Main.purs

@@ -0,0 +1 @@
+module Lib.Main where

test-fixtures/monorepo/local-packages-work-with-solver/spago.yaml

@@ -0,0 +1 @@
+workspace: {}

test/Spago/Build/Polyrepo.purs

@@ -189,6 +189,11 @@ spec = Spec.describe "polyrepo" do
     spago [ "build" ] >>= shouldBeSuccess
     spago [ "build" ] >>= shouldBeSuccessErr (fixture "monorepo/ignore-nested-workspaces/expected-stderr.txt")
 
+  Spec.it "it's possible to reference local packages when using the solver" \{ spago, fixture } -> do
+    FS.copyTree { src: fixture "monorepo/local-packages-work-with-solver", dst: "." }
+    spago [ "build" ] >>= shouldBeSuccess
+    spago [ "build" ] >>= shouldBeSuccessErr (fixture "monorepo/local-packages-work-with-solver/expected-stderr.txt")
+
   Spec.describe "warning censoring and error-promotion" do
     let
       setupPackageWithUnusedNameWarning packageName deps strict censorShadowedName includeTestCode = do