feat(fix-mode): warn to stderr when fixes not applied (#85)

__tests__/report-unapplied-fixes.spec.ts

@@ -0,0 +1,94 @@
+import { getUnappliedFixesWarnings } from '../src/utils/report-unapplied-fixes';
+import type { BatchLintItem } from '../src/types';
+
+const makeItem = (overrides: Partial<BatchLintItem> = {}): BatchLintItem => ({
+  path: 'doc.md',
+  lintResult: [],
+  ...overrides,
+});
+
+describe('getUnappliedFixesWarnings', () => {
+  test('returns no warnings for an empty result', () => {
+    expect(getUnappliedFixesWarnings([])).toEqual([]);
+  });
+
+  test('returns no warnings when fixedResult is null', () => {
+    const result: BatchLintItem[] = [makeItem({ fixedResult: null })];
+    expect(getUnappliedFixesWarnings(result)).toEqual([]);
+  });
+
+  test('returns no warnings when notAppliedFixes is empty', () => {
+    const result: BatchLintItem[] = [
+      makeItem({ fixedResult: { result: 'x', notAppliedFixes: [] } }),
+    ];
+    expect(getUnappliedFixesWarnings(result)).toEqual([]);
+  });
+
+  test('warns once with the correct count for a single unapplied fix', () => {
+    const result: BatchLintItem[] = [
+      makeItem({
+        path: 'a.md',
+        fixedResult: {
+          result: 'x',
+          notAppliedFixes: [{ range: [0, 1], text: 'y' }],
+        },
+      }),
+    ];
+    expect(getUnappliedFixesWarnings(result)).toEqual([
+      '[lint-md] a.md: 1 fixes were not applied due to conflicts.',
+    ]);
+  });
+
+  test('reports the count for multiple unapplied fixes and preserves the path', () => {
+    const result: BatchLintItem[] = [
+      makeItem({
+        path: 'conflict.md',
+        fixedResult: {
+          result: 'x',
+          notAppliedFixes: [
+            { range: [0, 1], text: 'y' },
+            { range: [2, 3], text: 'z' },
+            { range: [4, 5], text: 'w' },
+          ],
+        },
+      }),
+    ];
+    expect(getUnappliedFixesWarnings(result)).toEqual([
+      '[lint-md] conflict.md: 3 fixes were not applied due to conflicts.',
+    ]);
+  });
+
+  test('only warns for files that have unapplied fixes', () => {
+    const result: BatchLintItem[] = [
+      makeItem({
+        path: 'ok.md',
+        fixedResult: { result: 'x', notAppliedFixes: [] },
+      }),
+      makeItem({
+        path: 'bad.md',
+        fixedResult: {
+          result: 'x',
+          notAppliedFixes: [{ range: [0, 1], text: 'y' }],
+        },
+      }),
+    ];
+    expect(getUnappliedFixesWarnings(result)).toEqual([
+      '[lint-md] bad.md: 1 fixes were not applied due to conflicts.',
+    ]);
+  });
+
+  test('sanitizes file path in warning output', () => {
+    const result: BatchLintItem[] = [
+      makeItem({
+        path: 'bad\u001B[31m.md\nnext-line',
+        fixedResult: {
+          result: 'x',
+          notAppliedFixes: [{ range: [0, 1], text: 'y' }],
+        },
+      }),
+    ];
+
+    expect(getUnappliedFixesWarnings(result)[0]).not.toContain('\u001B');
+    expect(getUnappliedFixesWarnings(result)[0]).not.toContain('\n');
+  });
+});

src/lint-md.ts

@@ -18,6 +18,7 @@ import type { CLIOptions, ThreadCount } from './types';
 import { loadMdFiles } from './utils/load-md-files';
 import { getReportData } from './utils/get-report-data';
 import { filterFilesByMaxSize } from './utils/filter-by-max-size';
+import { getUnappliedFixesWarnings } from './utils/report-unapplied-fixes';
 
 program
   .version(
@@ -178,6 +179,10 @@ program
             .map(({ path, fixedResult }) => () => safeWriteFile(path, fixedResult!.result)),
           effectiveThreads
         );
+
+        for (const warning of getUnappliedFixesWarnings(lintResult)) {
+          console.error(warning);
+        }
       }
     }
     catch (e) {

src/utils/report-unapplied-fixes.ts

@@ -0,0 +1,22 @@
+import type { BatchLintItem } from '../types';
+import { sanitizeTerminalText } from './sanitize-terminal';
+
+// Returns stderr warning lines for files whose --fix pass left fixes
+// unapplied due to conflicts. `fixedResult.notAppliedFixes` (from
+// @lint-md/core) contains only the final-round conflicting fixes after
+// core stopped dropping them across rounds, so the range coordinates are
+// based on the returned result text and safe to report directly.
+export const getUnappliedFixesWarnings = (lintResult: BatchLintItem[]): string[] => {
+  const warnings: string[] = [];
+
+  for (const item of lintResult) {
+    const count = item.fixedResult?.notAppliedFixes?.length ?? 0;
+    if (count > 0) {
+      warnings.push(
+        `[lint-md] ${sanitizeTerminalText(item.path)}: ${count} fixes were not applied due to conflicts.`
+      );
+    }
+  }
+
+  return warnings;
+};