Refactor bsc finding logic

Author: chenglou

server/src/constants.ts

@@ -3,15 +3,15 @@ import * as path from "path";
 // See https://microsoft.github.io/language-server-protocol/specification Abstract Message
 // version is fixed to 2.0
 export let jsonrpcVersion = "2.0";
-export let bscExePartialPath = path.join(
+export let bscNativeReScriptPartialPath = path.join(
   "node_modules",
-  "bs-platform",
+  "rescript",
   process.platform,
   "bsc.exe"
 );
-export let bscExeReScriptPartialPath = path.join(
+export let bscNativePartialPath = path.join(
   "node_modules",
-  "rescript",
+  "bs-platform",
   process.platform,
   "bsc.exe"
 );

server/src/server.ts

@@ -466,13 +466,13 @@ function onMessage(msg: m.Message) {
         send(fakeSuccessResponse);
         send(response);
       } else {
-        // See comment on findBscExeDirOfFile for why we need
+        // See comment on findBscNativeDirOfFile for why we need
         // to recursively search for bsc.exe upward
-        let bscExeDir = utils.findBscExeDirOfFile(filePath);
-        if (bscExeDir === null) {
+        let bscNativePath = utils.findBscNativeOfFile(filePath);
+        if (bscNativePath === null) {
           let params: p.ShowMessageParams = {
             type: p.MessageType.Error,
-            message: `Cannot find a nearby bsc.exe in bs-platform or rescript. It's needed for formatting.`,
+            message: `Cannot find a nearby bsc.exe in rescript or bs-platform. It's needed for formatting.`,
           };
           let response: m.NotificationMessage = {
             jsonrpc: c.jsonrpcVersion,
@@ -482,16 +482,11 @@ function onMessage(msg: m.Message) {
           send(fakeSuccessResponse);
           send(response);
         } else {
-          let bscExePath1 = path.join(bscExeDir, c.bscExeReScriptPartialPath);
-          let bscExePath2 = path.join(bscExeDir, c.bscExePartialPath);
-          let resolvedBscExePath = fs.existsSync(bscExePath1)
-            ? bscExePath1
-            : bscExePath2;
           // code will always be defined here, even though technically it can be undefined
           let code = getOpenedFileContent(params.textDocument.uri);
-          let formattedResult = utils.formatUsingValidBscExePath(
+          let formattedResult = utils.formatUsingValidBscNativePath(
             code,
-            resolvedBscExePath,
+            bscNativePath,
             extension === c.resiExt
           );
           if (formattedResult.kind === "success") {

server/src/utils.ts

@@ -5,8 +5,6 @@ import * as path from "path";
 import * as t from "vscode-languageserver-types";
 import fs from "fs";
 import * as os from "os";
-import { fileURLToPath } from "url";
-import { RequestMessage } from "vscode-languageserver-protocol";
 
 let tempFilePrefix = "rescript_format_file_" + process.pid + "_";
 let tempFileId = 0;
@@ -45,21 +43,25 @@ export let findProjectRootOfFile = (
 // Also, if someone's ever formatting a regular project setup's dependency
 // (which is weird but whatever), they'll at least find an upward bs-platform
 // from the dependent.
-export let findBscExeDirOfFile = (
+export let findBscNativeOfFile = (
   source: p.DocumentUri
 ): null | p.DocumentUri => {
   let dir = path.dirname(source);
-  let bscExePath1 = path.join(dir, c.bscExeReScriptPartialPath);
-  let bscExePath2 = path.join(dir, c.bscExePartialPath);
-  if (fs.existsSync(bscExePath1) || fs.existsSync(bscExePath2)) {
-    return dir;
+  // The rescript package's rescript command is a JS wrapper. `rescript format`
+  // also invokes another JS wrapper. _That_ JS wrapper ultimately calls the
+  // (unexposed) bsc -format anyway.
+  let bscNativeReScriptPath = path.join(dir, c.bscNativeReScriptPartialPath);
+  let bscNativePath = path.join(dir, c.bscNativePartialPath);
+
+  if (fs.existsSync(bscNativeReScriptPath)) {
+    return bscNativeReScriptPath
+  } else if (fs.existsSync(bscNativePath)) {
+    return bscNativePath
+  } else if (dir === source) {
+    // reached the top
+    return null
   } else {
-    if (dir === source) {
-      // reached the top
-      return null;
-    } else {
-      return findBscExeDirOfFile(dir);
-    }
+    return findBscNativeOfFile(dir);
   }
 };
 
@@ -72,9 +74,9 @@ type execResult =
     kind: "error";
     error: string;
   };
-export let formatUsingValidBscExePath = (
+export let formatUsingValidBscNativePath = (
   code: string,
-  bscExePath: p.DocumentUri,
+  bscNativePath: p.DocumentUri,
   isInterface: boolean
 ): execResult => {
   let extension = isInterface ? c.resiExt : c.resExt;
@@ -83,7 +85,7 @@ export let formatUsingValidBscExePath = (
     encoding: "utf-8",
   });
   try {
-    let result = childProcess.execFileSync(bscExePath, [
+    let result = childProcess.execFileSync(bscNativePath, [
       "-color",
       "never",
       "-format",