Make ESLint report fatal error for files with dirty index

Author: paleite

src/git.ts

@@ -81,6 +81,27 @@ const getGitFileList = (): string[] => {
   return gitFileListCache;
 };
 
+const hasCleanIndex = (filePath: string): boolean => {
+  const command = [
+    "git",
+    "diff",
+    "--quiet",
+    "--relative",
+    "--unified=0",
+    "--",
+    sanitizeFilePath(filePath),
+  ].join(" ");
+
+  let result = true;
+  try {
+    child_process.execSync(command).toString();
+  } catch (err: unknown) {
+    result = false;
+  }
+
+  return result;
+};
+
 const isHunkHeader = (input: string) => {
   const hunkHeaderRE = new RegExp(/^@@ [^@]* @@/);
   return hunkHeaderRE.exec(input);
@@ -131,5 +152,11 @@ const getRangesForDiff = (diff: string): Range[] =>
     .map(getRangeForChangedLines)
     .filter(removeNullRanges);
 
-export { getDiffForFile, getRangesForDiff, getDiffFileList, getGitFileList };
+export {
+  getDiffForFile,
+  getRangesForDiff,
+  getDiffFileList,
+  getGitFileList,
+  hasCleanIndex,
+};
 export type { Range };

src/processors.ts

@@ -1,6 +1,11 @@
 import type { Linter } from "eslint";
 import type { Range } from "./git";
-import { getDiffFileList, getDiffForFile, getRangesForDiff } from "./git";
+import {
+  getDiffFileList,
+  getDiffForFile,
+  getRangesForDiff,
+  hasCleanIndex,
+} from "./git";
 
 const STAGED = true;
 
@@ -27,6 +32,21 @@ const getPostProcessor = (staged = false) => (
   messages: Linter.LintMessage[][],
   filename: string
 ): Linter.LintMessage[] => {
+  if (staged && !hasCleanIndex(filename)) {
+    const fatal = true;
+    const message = `${filename} has unstaged changes. Please stage or remove the changes.`;
+    const severity: Linter.Severity = 2;
+    const fatalError: Linter.LintMessage = {
+      fatal,
+      message,
+      severity,
+      column: 0,
+      line: 0,
+      ruleId: null,
+    };
+    return [fatalError];
+  }
+
   return messages
     .map((message) => {
       const filteredMessage = message.filter(({ fatal, line }) => {