fix: probe for an executable at a relative dprint.path on Windows

src/executable/DprintExecutable.ts

@@ -81,7 +81,11 @@ export class DprintExecutable {
   static async resolveCommand(options: DprintExecutableOptions): Promise<DprintCommand> {
     const command = await getCommand(options);
     return process.platform === "win32"
-      ? await resolveWindowsCommand(command, commandPath => which(commandPath, whichEnvironment))
+      ? await resolveWindowsCommand(
+        command,
+        commandPath => which(commandPath, whichEnvironment),
+        process.env.PATHEXT,
+      )
       : command;
   }
 

src/executable/command.test.ts

@@ -72,6 +72,11 @@ describe("getCommandLaunchInfo", () => {
       getCommandLaunchInfo({ kind: "setting", path: "./bin/dprint.bat", cwd: "C:\\project" }, ["-v"], "win32").command,
       "\"C:\\project\\bin\\dprint.bat\" \"-v\"",
     );
+    assert.strictEqual(
+      getCommandLaunchInfo({ kind: "setting", path: ".vscode/dprint.BAT", cwd: "C:\\project" }, ["-v"], "win32")
+        .command,
+      "\"C:\\project\\.vscode\\dprint.BAT\" \"-v\"",
+    );
   });
 });
 
@@ -89,7 +94,7 @@ describe("resolveWindowsCommand", () => {
     const searched: string[] = [];
     const which = (command: string) => {
       searched.push(command);
-      return Promise.resolve(command === "dprint" ? "C:\\npm prefix\\dprint.cmd" : `${command}.exe`);
+      return Promise.resolve(command === "dprint" ? "C:\\npm prefix\\dprint.cmd" : command.replace(/\.EXE$/, ".exe"));
     };
     assert.deepStrictEqual(
       await resolveWindowsCommand({ kind: "path", path: "dprint" }, which),
@@ -99,7 +104,51 @@ describe("resolveWindowsCommand", () => {
       await resolveWindowsCommand({ kind: "setting", path: "./bin/dprint", cwd: "C:\\project" }, which),
       { kind: "setting", path: "C:\\project\\bin\\dprint.exe", cwd: "C:\\project" },
     );
-    assert.deepStrictEqual(searched, ["dprint", "C:\\project\\bin\\dprint"]);
+    assert.deepStrictEqual(searched, ["dprint", "C:\\project\\bin\\dprint.EXE"]);
+  });
+
+  it("prefers a file with an executable extension over the file at the path", async () => {
+    // ex. a `dprint` shell script for other platforms beside a `dprint.bat`
+    const files = ["C:\\project\\.vscode\\dprint", "C:\\project\\.vscode\\dprint.bat"];
+    const which = (command: string) =>
+      Promise.resolve(files.find(file => file.toLowerCase() === command.toLowerCase()));
+    for (const settingPath of [".vscode/dprint", ".vscode\\dprint", "./.vscode/dprint"]) {
+      assert.deepStrictEqual(
+        await resolveWindowsCommand({ kind: "setting", path: settingPath, cwd: "C:\\project" }, which, ".EXE;.BAT"),
+        { kind: "setting", path: "C:\\project\\.vscode\\dprint.bat", cwd: "C:\\project" },
+      );
+    }
+  });
+
+  it("searches the launchable extensions in order and only once for a path with an extension", async () => {
+    const searched: string[] = [];
+    const which = (command: string) => {
+      searched.push(command);
+      return Promise.resolve(undefined);
+    };
+    const pathExt = ".COM;.EXE;.BAT;.CMD;.VBS;.JS";
+    await resolveWindowsCommand({ kind: "path", path: "C:/bin/dprint" }, which, pathExt);
+    await resolveWindowsCommand({ kind: "setting", path: "bin/dprint.Cmd", cwd: "C:\\project" }, which, pathExt);
+    await resolveWindowsCommand({ kind: "setting", path: "\\\\srv\\share\\dprint.exe", cwd: "C:\\project" }, which);
+    await resolveWindowsCommand({ kind: "setting", path: "C:bin\\dprint.exe", cwd: "C:\\project" }, which);
+    assert.deepStrictEqual(searched, [
+      "C:/bin/dprint.COM",
+      "C:/bin/dprint.EXE",
+      "C:/bin/dprint.BAT",
+      "C:/bin/dprint.CMD",
+      "C:/bin/dprint",
+      "C:\\project\\bin\\dprint.Cmd",
+      "\\\\srv\\share\\dprint.exe",
+      "C:\\project\\bin\\dprint.exe",
+    ]);
+  });
+
+  it("uses the file at the path when there's none with an executable extension", async () => {
+    const which = (command: string) => Promise.resolve(command === "C:\\bin\\dprint" ? command : undefined);
+    assert.deepStrictEqual(
+      await resolveWindowsCommand({ kind: "setting", path: "C:\\bin\\dprint", cwd: "C:\\project" }, which),
+      { kind: "setting", path: "C:\\bin\\dprint", cwd: "C:\\project" },
+    );
   });
 
   it("keeps the command when the file isn't found", async () => {

src/executable/command.ts

@@ -48,13 +48,24 @@ export function expandWindowsEnvVars(text: string, env: { [name: string]: string
  * Resolves the executable file of a command on Windows (ex. `dprint` to
  * `C:\bin\dprint.exe`) so that it can be launched without cmd.exe when possible.
  * The command is kept as-is when the file isn't found.
+ *
+ * Like cmd.exe, a file with an executable extension is preferred over the file at
+ * a path without one (ex. `bin/dprint.bat` over a `bin/dprint` shell script that's
+ * there for other platforms).
  */
 export async function resolveWindowsCommand(
   command: DprintCommand,
   which: (command: string) => Promise<string | undefined>,
+  pathExt?: string,
 ): Promise<DprintCommand> {
-  const filePath = await which(getWindowsCommandPath(command));
-  return filePath == null ? command : { ...command, path: filePath };
+  const commandPath = getWindowsCommandPath(command);
+  for (const candidate of [...getWindowsExecutableCandidates(commandPath, pathExt), commandPath]) {
+    const filePath = await which(candidate);
+    if (filePath != null) {
+      return { ...command, path: filePath };
+    }
+  }
+  return command;
 }
 
 /** Gets the text to display for the command. */
@@ -102,11 +113,31 @@ export function getCommandLaunchInfo(
 }
 
 function getWindowsCommandPath(command: DprintCommand) {
-  return command.kind === "setting" && command.cwd != null && isRelativePath(command.path)
-    ? path.win32.join(command.cwd, command.path)
+  return command.kind === "setting" && command.cwd != null && isWindowsRelativePath(command.path)
+    // resolve instead of join for a drive-relative path (ex. `C:bin\dprint`)
+    ? path.win32.resolve(command.cwd, command.path)
     : command.path;
 }
 
+/** Gets the path with each executable extension when it's a file path without one. */
+function getWindowsExecutableCandidates(commandPath: string, pathExt: string | undefined) {
+  if (!/[\\/]/.test(commandPath)) {
+    return []; // a command name, which is searched for on the path with the extensions
+  }
+  const extensions = (pathExt ?? ".EXE;.CMD;.BAT;.COM").split(";").map(ext => ext.trim()).filter(ext => ext.length > 0);
+  const lowerCasePath = commandPath.toLowerCase();
+  if (extensions.some(ext => lowerCasePath.endsWith(ext.toLowerCase()))) {
+    return [];
+  }
+  // only the extensions that can be launched (ex. not a `dprint.js` beside the file)
+  return extensions.filter(ext => /^\.(exe|com|cmd|bat)$/i.test(ext)).map(ext => commandPath + ext);
+}
+
+/** If it's a file path relative to the folder (ex. `bin/dprint`) rather than a command name. */
+function isWindowsRelativePath(commandPath: string) {
+  return /[\\/]/.test(commandPath) && !path.win32.isAbsolute(commandPath);
+}
+
 function getPosixSettingCommand(command: DprintCommand & { kind: "setting" }) {
   // double quotes so the shell expands the setting (ex. `$HOME`)
   const settingText = `"${command.path.replace(/"/g, "\\\"")}"`;