Stop formatting unknown files with babel parser

changelog_unreleased/api/14718.md

@@ -0,0 +1,12 @@
+#### Stop format unknown files with `babel` parser (#14718 by @fisker)
+
+```console
+await prettier.format("foo")
+
+// Prettier stable
+No parser and no filepath given, using 'babel' the parser now but this will throw an error in the future. Please specify a parser or a filepath so one can be inferred.
+'foo;\n'
+
+// Prettier main
+UndefinedParserError: No parser and no file path given, couldn't infer a parser.
+```

src/main/normalize-format-options.js

@@ -20,28 +20,11 @@ const formatOptionsHiddenDefaults = {
 async function normalizeFormatOptions(options, opts = {}) {
   const rawOptions = { ...options };
 
-  const supportOptions = getSupportInfo({
-    plugins: options.plugins,
-    showDeprecated: true,
-  }).options;
-
-  const defaults = {
-    ...formatOptionsHiddenDefaults,
-    ...Object.fromEntries(
-      supportOptions
-        .filter((optionInfo) => optionInfo.default !== undefined)
-        .map((option) => [option.name, option.default])
-    ),
-  };
   if (!rawOptions.parser) {
     if (!rawOptions.filepath) {
-      const logger = opts.logger || console;
-      logger.warn(
-        "No parser and no filepath given, using 'babel' the parser now " +
-          "but this will throw an error in the future. " +
-          "Please specify a parser or a filepath so one can be inferred."
+      throw new UndefinedParserError(
+        "No parser and no file path given, couldn't infer a parser."
       );
-      rawOptions.parser = "babel";
     } else {
       rawOptions.parser = inferParser(rawOptions, {
         physicalFile: rawOptions.filepath,
@@ -54,6 +37,20 @@ async function normalizeFormatOptions(options, opts = {}) {
     }
   }
 
+  const supportOptions = getSupportInfo({
+    plugins: options.plugins,
+    showDeprecated: true,
+  }).options;
+
+  const defaults = {
+    ...formatOptionsHiddenDefaults,
+    ...Object.fromEntries(
+      supportOptions
+        .filter((optionInfo) => optionInfo.default !== undefined)
+        .map((option) => [option.name, option.default])
+    ),
+  };
+
   const parserPlugin = getParserPluginByParserName(
     rawOptions.plugins,
     rawOptions.parser