feat: support --report-unused-ignore

#136

README.md

@@ -59,6 +59,7 @@ name | type | description
 `--cache-directory` | string? | [set cache directory](#enable-cache)(Added in `v2.24`)
 `--not-only-in-cwd` | boolean? | include results outside current working directory(Added in `v2.26`)
 `--json-output` | boolean? | output results as JSON(Added in `v2.27`)
+`--report-unused-ignore` | boolean? | report unused [ignore line](#ignore-line) directives(Added in `v2.28`)
 
 ### strict mode
 
@@ -128,6 +129,7 @@ This tool will ignore the files, eg: `--ignore-files "demo1/*.ts" --ignore-files
     "cacheDirectory": "custom-directory", // same as --cache-directory (Added in `v2.24`)
     "notOnlyInCWD": true, // same as --not-only-in-cwd (Added in `v2.26`)
     "jsonOutput": true, // same as --json-output (Added in `v2.27`)
+    "reportUnusedIgnore": true, // same as --report-unused-ignore (Added in `v2.28`)
   },
 ```
 
@@ -142,6 +144,13 @@ try {
 }
 ```
 
+The `--report-unused-ignore` can report unused ignore line directives.(Added in `v2.28`)
+
+```ts
+// type-coverage:ignore-next-line
+const a = 1 // <- this line is marked to ignore `any`, but there is no `any` here now. 
+```
+
 ## migrate to stricter typescript
 
 Create a new tsconfig file(eg: `tconfig.type-coverage.json`) with stricter config, that extends from `tsc`'s `tsconfig.json`
@@ -212,6 +221,7 @@ export interface LintOptions {
   reportSemanticError: boolean // Added in v2.22
   cacheDirectory: string // Added in v2.24
   notOnlyInCWD?: boolean, // Added in v2.26
+  reportUnusedIgnore: boolean, // Added in v2.28
 }
 
 export interface FileTypeCheckResult {

clean-scripts.config.ts

@@ -14,7 +14,7 @@ export default {
       ],
       dependencies: d.dependencies
     }))),
-    ...workspaces.map((d) => `node packages/cli/dist/index.js -p ${d.path}/src --detail --strict --suppressError`)
+    ...workspaces.map((d) => `node packages/cli/dist/index.js -p ${d.path}/src --detail --strict --report-unused-ignore --suppressError`)
   ],
   lint: {
     ts: `eslint --ext .js,.ts ${tsFiles}`,

packages/cli/src/index.ts

@@ -72,6 +72,7 @@ function printHelp() {
 --cache-directory           string?   set cache directory
 --not-only-in-cwd           boolean?  include results outside current working directory
 --json-output               boolean?  output results as JSON
+--report-unused-ignore      boolean?  report unused ignore line directives
   `)
 }
 
@@ -111,6 +112,7 @@ interface CliArgs extends BaseArgs {
   ['update-if-higher']: boolean
 
   ['report-semantic-error']: boolean
+  ['report-unused-ignore']: boolean
   ['cache-directory']: string
   ['not-only-in-cwd']: boolean
   ['json-output']: boolean
@@ -134,6 +136,7 @@ interface PkgArgs extends BaseArgs {
   noDetailWhenFailed: boolean
   updateIfHigher: boolean
   reportSemanticError: boolean
+  reportUnusedIgnore: boolean
   cacheDirectory: string
   notOnlyInCWD: boolean
   jsonOutput: boolean
@@ -182,6 +185,7 @@ async function executeCommandLine() {
     historyFile,
     noDetailWhenFailed,
     reportSemanticError,
+    reportUnusedIgnore,
     cacheDirectory,
     notOnlyInCWD,
   } = await getTarget(argv);
@@ -200,6 +204,7 @@ async function executeCommandLine() {
       ignoreObject,
       ignoreEmptyType,
       reportSemanticError,
+      reportUnusedIgnore,
       cacheDirectory,
       notOnlyInCWD,
       files: argv['--'].length > 0 ? argv['--'] : undefined,
@@ -302,6 +307,7 @@ async function getTarget(argv: CliArgs) {
     const historyFile = getArgOrCfgVal(['history-file', 'historyFile'])
     const noDetailWhenFailed = getArgOrCfgVal(['no-detail-when-failed', 'noDetailWhenFailed'])
     const reportSemanticError = getArgOrCfgVal(['report-semantic-error', 'reportSemanticError'])
+    const reportUnusedIgnore = getArgOrCfgVal(['report-unused-ignore', 'reportUnusedIgnore'])
     const cacheDirectory = getArgOrCfgVal(['cache-directory', 'cacheDirectory'])
     const notOnlyInCWD = getArgOrCfgVal(['not-only-in-cwd', 'notOnlyInCWD'])
 
@@ -328,6 +334,7 @@ async function getTarget(argv: CliArgs) {
       historyFile,
       noDetailWhenFailed,
       reportSemanticError,
+      reportUnusedIgnore,
       cacheDirectory,
       notOnlyInCWD,
     };

packages/core/src/checker.ts

@@ -3,12 +3,16 @@ import * as ts from 'typescript'
 import { FileAnyInfoKind, FileContext } from './interfaces'
 
 function collectAny(node: ts.Node, context: FileContext, kind: FileAnyInfoKind) {
-  const { file, sourceFile, typeCheckResult, ingoreMap, ignoreUnreadAnys, debug, processAny } = context
+  const { file, sourceFile, typeCheckResult, ignoreLines, ignoreUnreadAnys, debug, processAny } = context
   if (processAny !== undefined) {
     return processAny(node, context)
   }
   const { line, character } = ts.getLineAndCharacterOfPosition(sourceFile, node.getStart(sourceFile))
-  if (ingoreMap[file] && ingoreMap[file]?.has(line)) {
+  if (ignoreLines?.has(line)) {
+    if (!context.usedIgnoreLines) {
+      context.usedIgnoreLines = new Set()
+    }
+    context.usedIgnoreLines.add(line)
     return false
   }
   if (ignoreUnreadAnys && isEvolvingAssignment(node)) {

packages/core/src/core.ts

@@ -14,7 +14,7 @@ import {
 } from './interfaces'
 import { checkNode } from './checker'
 import { clearCacheOfDependencies, collectDependencies } from './dependencies'
-import { collectIgnoreMap } from './ignore'
+import { collectIgnoreLines } from './ignore'
 import { readCache, getFileHash, saveCache } from './cache'
 
 /**
@@ -106,7 +106,7 @@ export async function lint(project: string, options?: Partial<LintOptions>) {
       continue
     }
 
-    const ingoreMap = collectIgnoreMap(sourceFile, file)
+    const ignoreLines = collectIgnoreLines(sourceFile)
     const context: FileContext = {
       file,
       sourceFile,
@@ -122,7 +122,7 @@ export async function lint(project: string, options?: Partial<LintOptions>) {
       strict: lintOptions.strict,
       processAny: lintOptions.processAny,
       checker,
-      ingoreMap,
+      ignoreLines,
       ignoreNested: lintOptions.ignoreNested,
       ignoreAsAssertion: lintOptions.ignoreAsAssertion,
       ignoreTypeAssertion: lintOptions.ignoreTypeAssertion,
@@ -158,6 +158,20 @@ export async function lint(project: string, options?: Partial<LintOptions>) {
       checkNode(node, context)
     })
 
+    if (lintOptions.reportUnusedIgnore && ignoreLines) {
+      for (const line of ignoreLines) {
+        if (!context.usedIgnoreLines?.has(line)) {
+          anys.push({
+            line,
+            character: 0,
+            text: 'Unused ignore line directive(no problems reported on that line)',
+            kind: FileAnyInfoKind.unusedIgnore,
+            file,
+          })
+        }
+      }
+    }
+
     correctCount += context.typeCheckResult.correctCount
     totalCount += context.typeCheckResult.totalCount
     anys.push(...context.typeCheckResult.anys.map((a) => ({ file, ...a })))
@@ -209,6 +223,7 @@ const defaultLintOptions: LintOptions = {
   ignoreObject: false,
   ignoreEmptyType: false,
   reportSemanticError: false,
+  reportUnusedIgnore: false,
 }
 
 /**
@@ -253,7 +268,7 @@ export function lintSync(compilerOptions: ts.CompilerOptions, rootNames: string[
   const fileCounts =
     new Map<string, Pick<FileTypeCheckResult, 'correctCount' | 'totalCount'>>()
   for (const { sourceFile, file } of sourceFileInfos) {
-    const ingoreMap = collectIgnoreMap(sourceFile, file)
+    const ignoreLines = collectIgnoreLines(sourceFile)
     const context: FileContext = {
       file,
       sourceFile,
@@ -269,7 +284,7 @@ export function lintSync(compilerOptions: ts.CompilerOptions, rootNames: string[
       strict: lintOptions.strict,
       processAny: lintOptions.processAny,
       checker,
-      ingoreMap,
+      ignoreLines,
       ignoreNested: lintOptions.ignoreNested,
       ignoreAsAssertion: lintOptions.ignoreAsAssertion,
       ignoreTypeAssertion: lintOptions.ignoreTypeAssertion,

packages/core/src/ignore.ts

@@ -1,27 +1,26 @@
 import * as ts from 'typescript'
 import * as utils from 'tsutils/util'
 
-export function collectIgnoreMap(sourceFile: ts.SourceFile, file: string) {
-  const ingoreMap: { [file: string]: Set<number> } = {}
-
+export function collectIgnoreLines(sourceFile: ts.SourceFile) {
+  let ignoreLines: Set<number> | undefined
   utils.forEachComment(sourceFile, (_, comment) => {
     const commentText = comment.kind === ts.SyntaxKind.SingleLineCommentTrivia
       ? sourceFile.text.substring(comment.pos + 2, comment.end).trim()
       : sourceFile.text.substring(comment.pos + 2, comment.end - 2).trim()
     if (commentText.includes('type-coverage:ignore-next-line')) {
-      if (!ingoreMap[file]) {
-        ingoreMap[file] = new Set()
+      if (!ignoreLines) {
+        ignoreLines = new Set()
       }
       const line = ts.getLineAndCharacterOfPosition(sourceFile, comment.pos).line
-      ingoreMap[file]?.add(line + 1)
+      ignoreLines.add(line + 1)
     } else if (commentText.includes('type-coverage:ignore-line')) {
-      if (!ingoreMap[file]) {
-        ingoreMap[file] = new Set()
+      if (!ignoreLines) {
+        ignoreLines = new Set()
       }
       const line = ts.getLineAndCharacterOfPosition(sourceFile, comment.pos).line
-      ingoreMap[file]?.add(line)
+      ignoreLines.add(line)
     }
   })
 
-  return ingoreMap
+  return ignoreLines
 }

packages/core/src/interfaces.ts

@@ -30,6 +30,7 @@ export const enum FileAnyInfoKind {
   unsafeTypeAssertion = 4, // <string>foo
   unsafeNonNull = 5, // foo!
   semanticError = 6,
+  unusedIgnore = 7,
 }
 
 /**
@@ -45,6 +46,7 @@ export interface LintOptions extends CommonOptions {
   fileCounts: boolean,
   absolutePath?: boolean,
   reportSemanticError: boolean
+  reportUnusedIgnore: boolean
   cacheDirectory?: string
   notOnlyInCWD?: boolean
 }
@@ -87,7 +89,8 @@ export interface FileContext extends CommonOptions {
   typeCheckResult: FileTypeCheckResult
   checker: ts.TypeChecker
   catchVariables: { [variable: string]: boolean }
-  ingoreMap: { [file: string]: Set<number> }
+  ignoreLines?: Set<number>
+  usedIgnoreLines?: Set<number>
 }
 
 interface TypeCheckCache extends FileTypeCheckResult {