Make the --offline flag a little more offline

src/Spago/Command/Fetch.purs

@@ -519,6 +519,14 @@ getGitPackageInLocalCache name package = do
 getPackageDependencies :: forall a. PackageName -> Package -> Spago (FetchEnv a) (Maybe (ByEnv (Map PackageName Range)))
 getPackageDependencies packageName package = case package of
   RegistryVersion v -> do
+    -- Check if registry-index exists when offline
+    whenM (asks _.offline <#> eq Offline) do
+      unlessM (FS.exists Paths.registryIndexPath) do
+        die
+          [ "You are offline and the Registry Index is not cached locally."
+          , "Cannot look up dependencies for " <> PackageName.print packageName <> "@" <> Version.print v
+          , "Please connect to the internet and run 'spago install' first."
+          ]
     maybeManifest <- Registry.getManifestFromIndex packageName v
     pure $ maybeManifest <#> \(Manifest m) -> { core: m.dependencies, test: Map.empty }
   GitPackage p -> do

src/Spago/Git.purs

@@ -97,9 +97,15 @@ checkout { repo, ref } = Except.runExceptT $ void $ runGit [ "checkout", ref ] (
 
 fetch :: ∀ a path. Path.IsPath path => { repo :: path, remote :: String } -> Spago (GitEnv a) (Either String Unit)
 fetch { repo, remote } = do
-  remoteUrl <- runGit [ "remote", "get-url", remote ] (Just $ Path.toGlobal repo) # Except.runExceptT >>= rightOrDie
-  logInfo $ "Fetching from " <> remoteUrl
-  Except.runExceptT $ runGit_ [ "fetch", remote, "--tags" ] (Just $ Path.toGlobal repo)
+  { offline } <- ask
+  case offline of
+    Offline -> do
+      logDebug $ "Skipping fetch from remote '" <> remote <> "' because we are offline"
+      pure $ Left "Cannot fetch from remote while offline."
+    _ -> do
+      remoteUrl <- runGit [ "remote", "get-url", remote ] (Just $ Path.toGlobal repo) # Except.runExceptT >>= rightOrDie
+      logInfo $ "Fetching from " <> remoteUrl
+      Except.runExceptT $ runGit_ [ "fetch", remote, "--tags" ] (Just $ Path.toGlobal repo)
 
 getRefType :: ∀ a path. Path.IsPath path => { repo :: path, ref :: String } -> Spago (GitEnv a) (Either String String)
 getRefType { repo, ref } = Except.runExceptT $ runGit [ "cat-file", "-t", ref ] (Just $ Path.toGlobal repo)

src/Spago/Registry.purs

@@ -188,6 +188,16 @@ getRegistryFns registryBox registryLock = do
 
     -- Now that we are up to date with the Registry we init/refresh the database
     updatePackageSetsDb db
+
+    -- Check if registry directories exist when offline - the build should have already failed by now, but just in case..
+    case offline of
+      Offline -> do
+        unlessM (FS.exists Paths.registryPath) $
+          die "You are offline and the Registry is not cached locally. Please connect to the internet and run 'spago install' to cache the registry."
+        unlessM (FS.exists Paths.registryIndexPath) $
+          die "You are offline and the Registry Index is not cached locally. Please connect to the internet and run 'spago install' to cache the registry index."
+      _ -> pure unit
+
     pure fetchingFreshRegistry
 
   -- | Update the database with the latest package sets
@@ -211,12 +221,19 @@ getRegistryFns registryBox registryLock = do
   -- | List all the package sets versions available in the Registry repo
   getAvailablePackageSets :: ∀ a. Spago (LogEnv a) (Array Version)
   getAvailablePackageSets = do
-    { success: setVersions, fail: parseFailures } <- map (partitionEithers <<< map parseSetVersion) $ FS.ls Paths.packageSetsPath
-
-    unless (Array.null parseFailures) do
-      logDebug $ [ toDoc "Failed to parse some package-sets versions:" ] <> map (indent <<< toDoc <<< show) parseFailures
-
-    pure setVersions
+    packageSetsExists <- FS.exists Paths.packageSetsPath
+    if packageSetsExists then do
+      { success: setVersions, fail: parseFailures } <- map (partitionEithers <<< map parseSetVersion) $ FS.ls Paths.packageSetsPath
+
+      unless (Array.null parseFailures) do
+        logDebug $ [ toDoc "Failed to parse some package-sets versions:" ] <> map (indent <<< toDoc <<< show) parseFailures
+
+      pure setVersions
+    else do
+      die
+        [ "Package sets directory does not exist at " <> Path.quote Paths.packageSetsPath
+        , "Please connect to the internet and run 'spago install' to populate the registry cache."
+        ]
     where
     parseSetVersion str = Version.parse case String.stripSuffix (Pattern ".json") str of
       Nothing -> str
@@ -286,7 +303,7 @@ getManifestFromIndexImpl db name version = do
       manifests <- map (map (\m@(Manifest m') -> Tuple m'.version m)) case maybeManifests of
         Right ms -> pure $ NonEmptyArray.toUnfoldable ms
         Left err -> do
-          logWarn $ "Could not read package manifests from index, proceeding anyways. Error: " <> err
+          logWarn $ "Could not read package manifests for '" <> PackageName.print name <> "' from index. Error: " <> err
           pure []
       let versions = Map.fromFoldable manifests
       -- and memoize it