fix(types): narrow indexed-access + side-effect imports

Resolve 189 TS errors surfaced by the canonical fleet tsconfig.base
adoption (concrete config now sets allowImportingTsExtensions,
declaration, module, noEmit; base contributes noUncheckedIndexedAccess
+ noUncheckedSideEffectImports).

Techniques:
- Bounded array indexing in `for (let i = 0; i < length; i += 1)` loops:
  add `!` non-null assertion on `arr[i]` reads — the loop bound makes
  the access provably in-range, the assertion just teaches the checker.
- Two real bugs caught by the type widening:
  - check-consistency.mts: `Set` indexed as if it were an array
    (`categories[i]` on `Set<string>`) — switched to `for...of`.
  - check-patch-format.mts / validate-cache-versions.mts: same Set
    indexing shape — switched to `for...of`.

No `as` casts, no `@ts-ignore`, no API surface changes.

Author: jdalton

scripts/bump-cache-version.mts

@@ -47,7 +47,7 @@ export async function bumpAll(): Promise<BumpResult[]> {
 
   const results: BumpResult[] = []
   for (let i = 0, { length } = packages; i < length; i += 1) {
-    const pkg = packages[i]
+    const pkg = packages[i]!
     const result = await bumpCacheVersion(pkg)
     results.push(result)
   }

scripts/check-cascade-completeness.mts

@@ -129,7 +129,7 @@ export function collectDockerfileCopies(): Finding[] {
     withFileTypes: true,
   })
   for (let i = 0, { length } = packages; i < length; i += 1) {
-    const pkgEntry = packages[i]
+    const pkgEntry = packages[i]!
     if (!pkgEntry.isDirectory()) {
       continue
     }
@@ -160,7 +160,7 @@ export function collectDockerfileCopies(): Finding[] {
       continue
     }
     for (let i = 0, { length } = dockerFiles; i < length; i += 1) {
-      const df = dockerFiles[i]
+      const df = dockerFiles[i]!
       const dfPath = path.join(dockerDir, df)
       let contents: string
       try {
@@ -183,7 +183,7 @@ export function collectDockerfileCopies(): Finding[] {
         // Last token is the destination; everything else is a source.
         const sources = tokens.slice(0, -1)
         for (let i2 = 0, { length } = sources; i2 < length; i2 += 1) {
-          const src = sources[i2]
+          const src = sources[i2]!
           // Skip variable interpolations / quoted anomalies — out of scope.
           if (src.includes('${') || src.includes('"') || src === '.') {
             continue
@@ -249,7 +249,7 @@ export function collectMakefileIncludes(): Finding[] {
     withFileTypes: true,
   })
   for (let i = 0, { length } = packages; i < length; i += 1) {
-    const pkgEntry = packages[i]
+    const pkgEntry = packages[i]!
     if (!pkgEntry.isDirectory()) {
       continue
     }
@@ -261,7 +261,7 @@ export function collectMakefileIncludes(): Finding[] {
       continue
     }
     for (let i = 0, { length } = files; i < length; i += 1) {
-      const file = files[i]
+      const file = files[i]!
       const mkPath = path.join(pkgDir, file)
       let contents: string
       try {
@@ -324,7 +324,7 @@ export function collectTypeScriptImports(): Finding[] {
       return out
     }
     for (let i = 0, { length } = entries; i < length; i += 1) {
-      const entry = entries[i]
+      const entry = entries[i]!
       if (COLLECT_TS_IMPORTS_SKIP_DIRS.has(entry.name)) {
         continue
       }
@@ -342,7 +342,7 @@ export function collectTypeScriptImports(): Finding[] {
   }
   const files = walk(path.join(MONOREPO_ROOT, 'packages'))
   for (let i = 0, { length } = files; i < length; i += 1) {
-    const file = files[i]
+    const file = files[i]!
     let contents: string
     try {
       contents = readFileSync(file, 'utf8')
@@ -526,7 +526,7 @@ async function main(): Promise<void> {
   const seen = new Set<string>()
   const deduped: Finding[] = []
   for (let i = 0, { length } = surviving; i < length; i += 1) {
-    const f = surviving[i]
+    const f = surviving[i]!
     const key = `${f.consumer}|${f.gap}|${f.missingPath}`
     if (seen.has(key)) {
       continue
@@ -555,7 +555,7 @@ async function main(): Promise<void> {
     )
   }
   for (let i = 0, { length } = deduped; i < length; i += 1) {
-    const f = deduped[i]
+    const f = deduped[i]!
     printFinding(f, opts)
   }
   if (!opts.json) {

scripts/check-consistency.mts

@@ -258,7 +258,7 @@ export async function discoverPackages(): Promise<PackageInfo[]> {
   const packages: PackageInfo[] = []
 
   for (let i = 0, { length } = entries; i < length; i += 1) {
-    const entry = entries[i]
+    const entry = entries[i]!
     if (!entry.isDirectory()) {
       continue
     }
@@ -293,11 +293,11 @@ export async function checkRequiredFiles(
   log('\n[1/8] Checking required files...', colors.blue)
 
   for (let i = 0, { length } = packages; i < length; i += 1) {
-    const pkg = packages[i]
+    const pkg = packages[i]!
     const requiredFiles: string[] = ['package.json', 'README.md']
 
     for (let i = 0, { length } = requiredFiles; i < length; i += 1) {
-      const file = requiredFiles[i]
+      const file = requiredFiles[i]!
       const filePath = path.join(pkg.path, file)
       if (!existsSync(filePath)) {
         reportIssue(
@@ -338,7 +338,7 @@ export async function checkVitestConfig(
   )
 
   for (let i = 0, { length } = vitestPackages; i < length; i += 1) {
-    const pkg = vitestPackages[i]
+    const pkg = vitestPackages[i]!
     const configPath = path.join(pkg.path, 'vitest.config.mts')
     const config = await fs.readFile(configPath, 'utf8')
 
@@ -396,7 +396,7 @@ export async function checkTestScripts(packages: PackageInfo[]): Promise<void> {
   }
 
   for (let i = 0, { length } = packages; i < length; i += 1) {
-    const pkg = packages[i]
+    const pkg = packages[i]!
     const { scripts } = pkg.pkgJson
 
     if (!scripts || !scripts['test']) {
@@ -438,7 +438,7 @@ export async function checkCoverageScripts(
   const jsPackages = packages.filter(pkg => !C_PACKAGES.has(pkg.name))
 
   for (let i = 0, { length } = jsPackages; i < length; i += 1) {
-    const pkg = jsPackages[i]
+    const pkg = jsPackages[i]!
     const { devDependencies, scripts } = pkg.pkgJson
 
     // Check for cover script (standardized name across the workspace).
@@ -563,7 +563,7 @@ export async function checkBuildOutputStructure(
   log('[6/8] Checking build output structure...', colors.blue)
 
   for (let i = 0, { length } = packages; i < length; i += 1) {
-    const pkg = packages[i]
+    const pkg = packages[i]!
     const buildDir = path.join(pkg.path, 'build')
 
     if (!existsSync(buildDir)) {
@@ -599,7 +599,7 @@ export async function checkBuildOutputStructure(
       // Fall back to per-platform subdirs (binsuite, wasm, and native-addon styles).
       const entries = await fs.readdir(modeDir, { withFileTypes: true })
       for (let i = 0, { length } = entries; i < length; i += 1) {
-        const entry = entries[i]
+        const entry = entries[i]!
         if (!entry.isDirectory()) {
           continue
         }
@@ -651,7 +651,7 @@ export async function checkPackageJsonStructure(
   log('[7/8] Checking package.json structure...', colors.blue)
 
   for (let i = 0, { length } = packages; i < length; i += 1) {
-    const pkg = packages[i]
+    const pkg = packages[i]!
     const { description, license, name, scripts, type, version } = pkg.pkgJson
     const pkgJsonPath = path.join(pkg.path, 'package.json')
 
@@ -777,7 +777,7 @@ export async function checkWorkspaceDependencies(
   log('[8/8] Checking workspace dependencies...', colors.blue)
 
   for (let i = 0, { length } = packages; i < length; i += 1) {
-    const pkg = packages[i]
+    const pkg = packages[i]!
     const { dependencies = {}, devDependencies = {} } = pkg.pkgJson
     const allDeps = { ...dependencies, ...devDependencies }
     const pkgJsonPath = path.join(pkg.path, 'package.json')
@@ -847,7 +847,7 @@ export function collectPatterns(packages: PackageInfo[]): void {
   patternStats.total = packages.length
 
   for (let i = 0, { length } = packages; i < length; i += 1) {
-    const pkg = packages[i]
+    const pkg = packages[i]!
     // Collect script patterns
     if (pkg.pkgJson.scripts) {
       // oxlint-disable-next-line socket/prefer-cached-for-loop -- loop variable is destructured
@@ -1100,7 +1100,7 @@ export function displaySuggestions(suggestions: Suggestion[]): void {
   log('='.repeat(60), colors.bright)
 
   for (let i = 0, { length } = suggestions; i < length; i += 1) {
-    const suggestion = suggestions[i]
+    const suggestion = suggestions[i]!
     const confidenceColor =
       suggestion.level === 'HIGH' || suggestion.level === 'VERY HIGH'
         ? colors.green
@@ -1139,7 +1139,7 @@ export async function executeFixes(): Promise<void> {
   log('='.repeat(60), colors.bright)
 
   for (let i = 0, { length } = fixableIssues; i < length; i += 1) {
-    const issue = fixableIssues[i]
+    const issue = fixableIssues[i]!
     if (CLI_FLAGS.dryRun) {
       log('\n[DRY RUN] Would fix:', colors.yellow)
       log(`  ${issue.file}`, colors.blue)
@@ -1191,7 +1191,7 @@ export async function executeFixes(): Promise<void> {
     log(`Successfully fixed ${fixedIssues.length} issue(s)`, colors.green)
 
     for (let i = 0, { length } = fixedIssues; i < length; i += 1) {
-      const fixed = fixedIssues[i]
+      const fixed = fixedIssues[i]!
       log(`  ✓ ${fixed.file}`, colors.green)
     }
   }
@@ -1257,8 +1257,8 @@ async function main(): Promise<void> {
       ...issues.info.map(i => i.category),
     ])
 
-    for (let i = 0, { length } = categories; i < length; i += 1) {
-      const category = categories[i]
+    // oxlint-disable-next-line socket/prefer-cached-for-loop -- iterable is a Set (not array-indexed)
+    for (const category of categories) {
       const categoryIssues = {
         error: issues.error.filter(i => i.category === category),
         info: issues.info.filter(i => i.category === category),

scripts/check-mirror-docs.mts

@@ -127,7 +127,7 @@ export function walk(
       continue
     }
     for (let i = 0, { length } = entries; i < length; i += 1) {
-      const entry = entries[i]
+      const entry = entries[i]!
       const full = path.join(dir, entry.name)
       if (entry.isDirectory()) {
         queue.push(full)
@@ -153,7 +153,7 @@ export function collectOrphanDocs(): Finding[] {
   const docs = walk(DOCS_ROOT, r => r.endsWith('.md'))
   const findings: Finding[] = []
   for (let i = 0, { length } = docs; i < length; i += 1) {
-    const docRel = docs[i]
+    const docRel = docs[i]!
     // Doc naming convention: trim the trailing ".md" — the remaining
     // path (e.g. "lib/smol-http.js" or "lib/internal/.../version_subset.js")
     // is the expected source file name. Per CLAUDE.md, the JS extension
@@ -285,7 +285,7 @@ async function main(): Promise<void> {
     )
   }
   for (let i = 0, { length } = surviving; i < length; i += 1) {
-    const f = surviving[i]
+    const f = surviving[i]!
     printFinding(f, opts)
   }
   if (!opts.json) {

scripts/check-patch-format.mts

@@ -116,7 +116,7 @@ export function collectMultiplePatchesPerFileViolations(
   // and accumulate.
   const fileToPatches = new Map<string, string[]>()
   for (let i = 0, { length } = files; i < length; i += 1) {
-    const patchName = files[i]
+    const patchName = files[i]!
     const abs = path.join(dir, patchName)
     let content
     try {
@@ -134,8 +134,8 @@ export function collectMultiplePatchesPerFileViolations(
         minusFiles.add(match[1]!)
       }
     }
-    for (let i = 0, { length } = minusFiles; i < length; i += 1) {
-      const f = minusFiles[i]
+    // oxlint-disable-next-line socket/prefer-cached-for-loop -- iterable is a Set (not array-indexed)
+    for (const f of minusFiles) {
       const list = fileToPatches.get(f) ?? []
       list.push(patchName)
       fileToPatches.set(f, list)
@@ -179,7 +179,7 @@ export function collectNumberGapViolations(dir: string): Violation[] {
   const files = readdirSync(dir).filter(f => f.endsWith('.patch'))
   const numbered: Array<{ name: string; num: number }> = []
   for (let i = 0, { length } = files; i < length; i += 1) {
-    const name = files[i]
+    const name = files[i]!
     const num = numericPrefix(name)
     if (num !== undefined) {
       numbered.push({ name, num })
@@ -628,7 +628,7 @@ async function main(): Promise<void> {
   const allViolations: Violation[] = []
   let patchesScanned = 0
   for (let i = 0, { length } = PATCH_ROOTS; i < length; i += 1) {
-    const root = PATCH_ROOTS[i]
+    const root = PATCH_ROOTS[i]!
     const absRoot = path.join(MONOREPO_ROOT, root.dir)
     if (!existsSync(absRoot)) {
       continue
@@ -642,7 +642,7 @@ async function main(): Promise<void> {
       continue
     }
     for (let i = 0, { length } = files; i < length; i += 1) {
-      const f = files[i]
+      const f = files[i]!
       const abs = path.join(absRoot, f)
       try {
         const stat = statSync(abs)
@@ -679,7 +679,7 @@ async function main(): Promise<void> {
     )
   }
   for (let i = 0, { length } = surviving; i < length; i += 1) {
-    const v = surviving[i]
+    const v = surviving[i]!
     printViolation(v, opts)
   }
   if (!opts.json) {

scripts/check-regression-patterns.mts

@@ -419,7 +419,7 @@ export async function findNonExistentPnpmScripts(
   if (existsSync(pkgsDir)) {
     const entries = await fsPromises.readdir(pkgsDir, { withFileTypes: true })
     for (let i = 0, { length } = entries; i < length; i += 1) {
-      const entry = entries[i]
+      const entry = entries[i]!
       if (entry.isDirectory()) {
         await collectPackageScripts(
           path.join(pkgsDir, entry.name, 'package.json'),
@@ -435,7 +435,7 @@ export async function findNonExistentPnpmScripts(
   // convention.
   const placeholders = new Set(['bar', 'baz', 'foo', 'script'])
   for (let i = 0, { length } = rawMatches; i < length; i += 1) {
-    const m = rawMatches[i]
+    const m = rawMatches[i]!
     // Skip Claude Code permission-glob patterns like
     //   Bash(pnpm run check:*)
     // Those describe a class of allowed Bash invocations, not a
@@ -628,7 +628,7 @@ export function wrapText(
   const words = text.split(/\s+/)
   let line = ''
   for (let i = 0, { length } = words; i < length; i += 1) {
-    const w = words[i]
+    const w = words[i]!
     if (line.length + w.length + 1 > width) {
       out.push(pad + line)
       line = w
@@ -664,7 +664,7 @@ async function main(): Promise<void> {
 
   const allMatches: Match[] = []
   for (let i = 0, { length } = REGRESSIONS; i < length; i += 1) {
-    const regression = REGRESSIONS[i]
+    const regression = REGRESSIONS[i]!
     const matches =
       regression.id === 'docs-pnpm-run-nonexistent'
         ? await findNonExistentPnpmScripts(regression)
@@ -685,7 +685,7 @@ async function main(): Promise<void> {
   // Group by pattern for a readable summary first.
   const byPattern = new Map<string, Match[]>()
   for (let i = 0, { length } = allMatches; i < length; i += 1) {
-    const m = allMatches[i]
+    const m = allMatches[i]!
     const key = m.regression.id
     const arr = byPattern.get(key) || []
     arr.push(m)
@@ -694,15 +694,15 @@ async function main(): Promise<void> {
 
   if (opts.json) {
     for (let i = 0, { length } = allMatches; i < length; i += 1) {
-      const m = allMatches[i]
+      const m = allMatches[i]!
       printMatch(m, opts)
     }
   } else {
     logger.error(
       `Found ${allMatches.length} regression-pattern match${allMatches.length === 1 ? '' : 'es'} across ${byPattern.size} pattern${byPattern.size === 1 ? '' : 's'}:`,
     )
     for (let i = 0, { length } = allMatches; i < length; i += 1) {
-      const m = allMatches[i]
+      const m = allMatches[i]!
       printMatch(m, opts)
     }
     logger.log('')

scripts/check-version-consistency.mts

@@ -255,14 +255,14 @@ export async function collectMismatches(): Promise<Mismatch[]> {
   // Group package.json source entries by upstream name.
   const pkgByUpstream = new Map<string, PackageJsonSource>()
   for (let i = 0, { length } = pkgSources; i < length; i += 1) {
-    const s = pkgSources[i]
+    const s = pkgSources[i]!
     pkgByUpstream.set(s.upstream, s)
   }
 
   // For each submodule with a version comment, find a matching package.json
   // source entry (same upstream name) and compare.
   for (let i = 0, { length } = submodules; i < length; i += 1) {
-    const sub = submodules[i]
+    const sub = submodules[i]!
     if (!sub.versionComment) {
       continue
     }
@@ -397,7 +397,7 @@ async function main(): Promise<void> {
     )
   }
   for (let i = 0, { length } = surviving; i < length; i += 1) {
-    const m = surviving[i]
+    const m = surviving[i]!
     printMismatch(m, opts)
   }
   if (!opts.json) {