Split css parsers (#7932)

* Split css parsers

* pass function to parseWithParser

* Fix plugins parser

* Fix coverage fails

* coverage ignore

* Update project coverage target to 95%

.codecov.yml

@@ -7,4 +7,4 @@ coverage:
         target: 80%
     project:
       default:
-        target: auto
+        target: 95%

src/common/internal-plugins.js

@@ -88,10 +88,10 @@ module.exports = [
         return eval("require")("../language-css/parser-postcss").parsers.css;
       },
       get less() {
-        return eval("require")("../language-css/parser-postcss").parsers.css;
+        return eval("require")("../language-css/parser-postcss").parsers.less;
       },
       get scss() {
-        return eval("require")("../language-css/parser-postcss").parsers.css;
+        return eval("require")("../language-css/parser-postcss").parsers.scss;
       },
     },
   },

src/language-css/parser-postcss.js

@@ -523,7 +523,7 @@ function parseNestedCSS(node, options) {
   return node;
 }
 
-function parseWithParser(parser, text, options) {
+function parseWithParser(parse, text, options) {
   const parsed = parseFrontMatter(text);
   const { frontMatter } = parsed;
   text = parsed.content;
@@ -531,7 +531,7 @@ function parseWithParser(parser, text, options) {
   let result;
 
   try {
-    result = parser.parse(text);
+    result = parse(text);
   } catch (e) {
     if (typeof e.line !== "number") {
       throw e;
@@ -550,47 +550,52 @@ function parseWithParser(parser, text, options) {
   return result;
 }
 
-function requireParser(isSCSSParser) {
-  if (isSCSSParser) {
-    return require("postcss-scss");
+// TODO: make this only work on css
+function parseCss(text, parsers, options) {
+  const isSCSSParser = isSCSS(options.parser, text);
+  const parseFunctions = isSCSSParser
+    ? [parseScss, parseLess]
+    : [parseLess, parseScss];
+
+  let error;
+  for (const parse of parseFunctions) {
+    try {
+      return parse(text, parsers, options);
+    } catch (parseError) {
+      error = error || parseError;
+    }
   }
 
+  /* istanbul ignore next */
+  if (error) {
+    throw error;
+  }
+}
+
+function parseLess(text, parsers, options) {
   const lessParser = require("postcss-less");
-  return {
+  return parseWithParser(
     // Workaround for https://github.com/shellscape/postcss-less/issues/145
     // See comments for `replaceQuotesInInlineComments` in `loc.js`.
-    parse: (text) => lessParser.parse(replaceQuotesInInlineComments(text)),
-  };
+    (text) => lessParser.parse(replaceQuotesInInlineComments(text)),
+    text,
+    options
+  );
 }
 
-function parse(text, parsers, options) {
-  const hasExplicitParserChoice =
-    options.parser === "less" || options.parser === "scss";
-  const isSCSSParser = isSCSS(options.parser, text);
-
-  try {
-    return parseWithParser(requireParser(isSCSSParser), text, options);
-  } catch (originalError) {
-    if (hasExplicitParserChoice) {
-      throw originalError;
-    }
-
-    try {
-      return parseWithParser(requireParser(!isSCSSParser), text, options);
-    } catch (_secondError) {
-      throw originalError;
-    }
-  }
+function parseScss(text, parsers, options) {
+  const { parse } = require("postcss-scss");
+  return parseWithParser(parse, text, options);
 }
 
-const parser = {
-  parse,
+const postCssParser = {
   astFormat: "postcss",
   hasPragma,
   locStart(node) {
     if (node.source) {
       return node.source.startOffset;
     }
+    /* istanbul ignore next */
     return null;
   },
   locEnd(node) {
@@ -604,8 +609,17 @@ const parser = {
 // Export as a plugin so we can reuse the same bundle for UMD loading
 module.exports = {
   parsers: {
-    css: parser,
-    less: parser,
-    scss: parser,
+    css: {
+      ...postCssParser,
+      parse: parseCss,
+    },
+    less: {
+      ...postCssParser,
+      parse: parseLess,
+    },
+    scss: {
+      ...postCssParser,
+      parse: parseScss,
+    },
   },
 };