Report error for edge case for bsb-native. (#382)

* Report error for edge case for bsb-native.
... where .merlin has -backend but bsconfig's entries got updated and
don't have that backend anymore.

* merge in

Co-authored-by: Benjamin San Souci <benjamin.sansouci@gmail.com>

Author: jaredly

examples/example-react/package-lock.json

@@ -32,31 +32,41 @@ let rec getAffectedFiles = (root, lines) => switch lines {
 let runBuildCommand = (~reportDiagnostics, state, root, buildCommand) => {
   /** TODO check for a bsb.lock file & bail if it's there */
   /** TODO refactor so Dune projects don't get bsconfig.json handling below */
-  let%opt_consume (buildCommand, commandDirectory) = buildCommand;
-  Log.log(">> Build system running: " ++ buildCommand);
-  let (stdout, stderr, _success) = Commands.execFull(~pwd=commandDirectory, buildCommand);
-  Log.log(">>> stdout");
-  Log.log(Utils.joinLines(stdout));
-  Log.log(">>> stderr");
-  Log.log(Utils.joinLines(stderr));
-  let files = getAffectedFiles(commandDirectory, stdout @ stderr);
-  Log.log("Affected files: " ++ String.concat(" ", files));
-  let bsconfigJson = root /+ "bsconfig.json" |> Utils.toUri;
-  let bsconfigClean = ref(true);
-  files |. Belt.List.forEach(uri => {
-    if (Utils.endsWith(uri, "bsconfig.json")) {
-      bsconfigClean := false;
-      Log.log("Bsconfig.json sending");
-      reportDiagnostics(
-        uri, `BuildFailed(stdout @ stderr)
-        )
-    };
-    Hashtbl.remove(state.compiledDocuments, uri);
-    Hashtbl.replace(state.documentTimers, uri, Unix.gettimeofday() -. 0.01)
-  });
-  if (bsconfigClean^) {
-    Log.log("Cleaning bsconfig.json");
-    reportDiagnostics(bsconfigJson, `BuildSucceeded)
+  switch buildCommand {
+    | None => Ok()
+    | Some((buildCommand, commandDirectory)) =>
+      Log.log(">> Build system running: " ++ buildCommand);
+      let (stdout, stderr, _success) = Commands.execFull(~pwd=commandDirectory, buildCommand);
+      Log.log(">>> stdout");
+      Log.log(Utils.joinLines(stdout));
+      Log.log(">>> stderr");
+      let errors = Utils.joinLines(stderr);
+      Log.log(errors);
+      let%try _ = if (Utils.startsWith(errors, "Error: Could not find an item in the entries field to compile to ")) {
+        Error("Bsb-native " ++ errors ++ "\nHint: check your bsconfig's \"entries\".")
+      } else {
+        Ok();
+      };
+      let files = getAffectedFiles(commandDirectory, stdout @ stderr);
+      Log.log("Affected files: " ++ String.concat(" ", files));
+      let bsconfigJson = root /+ "bsconfig.json" |> Utils.toUri;
+      let bsconfigClean = ref(true);
+      files |. Belt.List.forEach(uri => {
+        if (Utils.endsWith(uri, "bsconfig.json")) {
+          bsconfigClean := false;
+          Log.log("Bsconfig.json sending");
+          reportDiagnostics(
+            uri, `BuildFailed(stdout @ stderr)
+            )
+        };
+        Hashtbl.remove(state.compiledDocuments, uri);
+        Hashtbl.replace(state.documentTimers, uri, Unix.gettimeofday() -. 0.01)
+      });
+      if (bsconfigClean^) {
+        Log.log("Cleaning bsconfig.json");
+        reportDiagnostics(bsconfigJson, `BuildSucceeded)
+      };
+      /* TODO report notifications here */
+      Ok()
   }
-  /* TODO report notifications here */
 };

src/analyze/BuildCommand.re

@@ -70,9 +70,9 @@ let newBsPackage = (~overrideBuildSystem=?, ~reportDiagnostics, state, rootPath)
   Log.log("- buildSystem: " ++ BuildSystem.show(buildSystem));
   Log.log("- build command: " ++ buildCommand);
 
-  if (state.settings.autoRebuild) {
+  let%try () = if (state.settings.autoRebuild) {
     BuildCommand.runBuildCommand(~reportDiagnostics, state, rootPath, Some((buildCommand, rootPath)));
-  };
+  } else { Ok() };
 
   let compiledBase = BuildSystem.getCompiledBase(rootPath, buildSystem);
   let%try stdLibDirectories = BuildSystem.getStdlib(rootPath, buildSystem);
@@ -331,9 +331,9 @@ let newJbuilderPackage = (~overrideBuildSystem=?, ~reportDiagnostics, state, roo
       }
   };
 
-  if (state.settings.autoRebuild) {
+  let%try () = if (state.settings.autoRebuild) {
     BuildCommand.runBuildCommand(~reportDiagnostics, state, rootPath, buildCommand);
-  };
+  } else { Ok() };
 
   let%try compilerPath = BuildSystem.getCompiler(projectRoot, buildSystem);
   let%try compilerVersion = BuildSystem.getCompilerVersion(compilerPath);

src/analyze/Packages.re

@@ -36,7 +36,8 @@ let checkPackageTimers = state => {
   Hashtbl.iter((_, package) => {
     if (package.rebuildTimer != 0. && package.rebuildTimer < Unix.gettimeofday()) {
       package.rebuildTimer = 0.;
-      BuildCommand.runBuildCommand(~reportDiagnostics, state, package.basePath, package.buildCommand);
+      // TODO report the error here
+      ignore @@ BuildCommand.runBuildCommand(~reportDiagnostics, state, package.basePath, package.buildCommand);
     }
   }, state.packagesByRoot)
 };