refactor: enable strict type checking of fs patches src

Author: jbedard

js/private/node-patches/fs.cjs

@@ -84,7 +84,7 @@ function patcher(roots) {
         if (process.env.VERBOSE_LOGS) {
             console.error('fs patcher called without any valid root paths ' + __filename);
         }
-        return;
+        return function () { };
     }
     const origLstat = fs.lstat.bind(fs);
     const origLstatSync = fs.lstatSync.bind(fs);
@@ -242,11 +242,11 @@ function patcher(roots) {
             return origReadlink(...args);
         }
         const cb = once(args[args.length - 1]);
-        args[args.length - 1] = function readlinkCb(err, str) {
+        args[args.length - 1] = function readlinkCb(err, p) {
             if (err)
                 return cb(err);
             const resolved = resolvePathLike(args[0]);
-            str = path.resolve(path.dirname(resolved), str);
+            const str = path.resolve(path.dirname(resolved), p);
             const escapedRoot = isEscape(resolved, str);
             if (escapedRoot) {
                 return nextHop(str, readlinkNextHopCb);
@@ -261,10 +261,12 @@ function patcher(roots) {
                             return cb(einval('readlink', args[0]));
                         }
                     }
-                    next = path.resolve(path.dirname(resolved), path.relative(path.dirname(str), next));
-                    if (next != resolved &&
-                        !isEscape(resolved, next, [escapedRoot])) {
-                        return cb(null, next);
+                    const resolvedNext = path.resolve(path.dirname(resolved), path.relative(path.dirname(str), next));
+                    if (resolvedNext != resolved &&
+                        !isEscape(resolved, resolvedNext, [
+                            escapedRoot,
+                        ])) {
+                        return cb(null, resolvedNext);
                     }
                     // The escape from the root is not mappable back into the root; throw EINVAL
                     return cb(einval('readlink', args[0]));
@@ -282,19 +284,14 @@ function patcher(roots) {
         const escapedRoot = isEscape(resolved, str);
         if (escapedRoot) {
             let next = nextHopSync(str);
-            if (!next) {
-                if (next == undefined) {
-                    // The escape from the root is not mappable back into the root; throw EINVAL
-                    throw enoent('readlink', args[0]);
-                }
-                else {
-                    // The escape from the root is not mappable back into the root; throw EINVAL
-                    throw einval('readlink', args[0]);
-                }
+            if (next === false) {
+                // The escape from the root is not mappable back into the root; throw EINVAL
+                throw enoent('readlink', args[0]);
             }
-            next = path.resolve(path.dirname(resolved), path.relative(path.dirname(str), next));
-            if (next != resolved && !isEscape(resolved, next, [escapedRoot])) {
-                return next;
+            const resolvedNext = path.resolve(path.dirname(resolved), path.relative(path.dirname(str), next));
+            if (resolvedNext != resolved &&
+                !isEscape(resolved, resolvedNext, [escapedRoot])) {
+                return resolvedNext;
             }
             // The escape from the root is not mappable back into the root; throw EINVAL
             throw einval('readlink', args[0]);
@@ -315,7 +312,7 @@ function patcher(roots) {
             if (err)
                 return cb(err);
             // user requested withFileTypes
-            if (result[0] && result[0].isSymbolicLink) {
+            if (result[0] && 'isSymbolicLink' in result[0]) {
                 Promise.all(result.map((v) => handleDirent(p, v)))
                     .then(() => {
                     cb(null, result);
@@ -452,7 +449,7 @@ function patcher(roots) {
             });
         };
         const origRead = dir.read.bind(dir);
-        dir.read = async function handleDirRead(cb) {
+        dir.read = function handleDirRead(cb) {
             if (typeof cb === 'function') {
                 origRead(function handleDirReadCb(err, entry) {
                     if (err)
@@ -461,13 +458,10 @@ function patcher(roots) {
                         cb(null, entry);
                     }, (err) => cb(err, null));
                 });
+                return undefined;
             }
             else {
-                const entry = await origRead();
-                if (entry) {
-                    await handleDirent(p, entry);
-                }
-                return entry;
+                return origRead().then((entry) => entry && handleDirent(p, entry));
             }
         };
         const origReadSync = dir.readSync.bind(dir);
@@ -476,13 +470,13 @@ function patcher(roots) {
         };
         return dir;
     }
-    async function handleDirent(p, v) {
+    function handleDirent(p, v) {
         if (!v.isSymbolicLink()) {
-            return v;
+            return Promise.resolve(v);
         }
         const f = path.resolve(p, v.name);
         return new Promise(function handleDirentExecutor(resolve, reject) {
-            return guardedReadLink(f, handleDirentReadLinkCb);
+            guardedReadLink(f, handleDirentReadLinkCb);
             function handleDirentReadLinkCb(str) {
                 if (f != str) {
                     return resolve(v);
@@ -524,7 +518,7 @@ function patcher(roots) {
         let escapedHop = false;
         readHopLink(maybe, function readNextHop(link) {
             if (link === HOP_NOT_FOUND) {
-                return cb(undefined);
+                return cb(false);
             }
             if (link !== HOP_NON_LINK) {
                 if (nested) {
@@ -619,7 +613,7 @@ function patcher(roots) {
         for (;;) {
             let link = readHopLinkSync(maybe);
             if (link === HOP_NOT_FOUND) {
-                return undefined;
+                return false;
             }
             if (link !== HOP_NON_LINK) {
                 if (nested) {
@@ -680,7 +674,7 @@ function patcher(roots) {
             nextHop(loc, function oneHopeNextCb(next) {
                 if (next == undefined) {
                     // file does not exist (broken link)
-                    return cb(enoent('realpath', start));
+                    return cb(enoent('realpath', start), undefined);
                 }
                 else if (!next) {
                     // we've hit a real file
@@ -691,7 +685,7 @@ function patcher(roots) {
         }
         oneHop(start, cb);
     }
-    function guardedRealPath(start, cb, escapedRoot = undefined) {
+    function guardedRealPath(start, cb, escapedRoot) {
         start = stringifyPathLike(start); // handle the "undefined" case (matches behavior as fs.realpath)
         function oneHop(loc, cb) {
             nextHop(loc, function guardedRealPathHopCb(next) {
@@ -704,7 +698,7 @@ function patcher(roots) {
                         }
                         else {
                             // something funky happened in the filesystem
-                            return cb(enoent('realpath', start));
+                            return cb(enoent('realpath', start), undefined);
                         }
                     });
                 }
@@ -733,7 +727,7 @@ function patcher(roots) {
             }
         }
     }
-    function guardedRealPathSync(start, escapedRoot = undefined) {
+    function guardedRealPathSync(start, escapedRoot) {
         start = stringifyPathLike(start); // handle the "undefined" case (matches behavior as fs.realpathSync)
         for (let loc = start, next;; loc = next) {
             next = nextHopSync(loc);