Prevent infinite recursion

src/config/normalize/lib/wild_wild_path/iterate/main.js

@@ -15,6 +15,7 @@ export const iterate = function* (
   query,
   { childFirst = false, sort = false, classes = false } = {},
 ) {
+  const parents = new Set([])
   const opts = { childFirst, sort, classes }
   const queryArrays = parseQuery(query)
   const entries = queryArrays.map((queryArray) => ({
@@ -23,10 +24,24 @@ export const iterate = function* (
     path: [],
     missing: false,
   }))
-  yield* iterateLevel(entries, 0, opts)
+  yield* iterateLevel({ entries, index: 0, parents, opts })
 }
 
-const iterateLevel = function* (entries, index, opts) {
+// `parents` is used to prevent infinite recursions when using ** together with
+// a value that includes references to itself
+const iterateLevel = function* ({
+  entries,
+  entries: [{ value }],
+  index,
+  parents,
+  opts,
+}) {
+  if (parents.has(value)) {
+    return
+  }
+
+  parents.add(value)
+
   const entriesA = expandRecursiveTokens(entries, index)
   const entriesB = removeDuplicates(entriesA)
   const parentEntry = getParentEntry(entriesB, index)
@@ -35,11 +50,19 @@ const iterateLevel = function* (entries, index, opts) {
     yield parentEntry
   }
 
-  yield* iterateChildEntries({ entries: entriesB, parentEntry, index, opts })
+  yield* iterateChildEntries({
+    entries: entriesB,
+    parentEntry,
+    index,
+    parents,
+    opts,
+  })
 
   if (parentEntry !== undefined && opts.childFirst) {
     yield parentEntry
   }
+
+  parents.delete(value)
 }
 
 const getParentEntry = function (entries, index) {
@@ -54,7 +77,13 @@ const normalizeEntry = function ({ value, path, missing }) {
   return { value, path, query, missing }
 }
 
-const iterateChildEntries = function* ({ entries, parentEntry, index, opts }) {
+const iterateChildEntries = function* ({
+  entries,
+  parentEntry,
+  index,
+  parents,
+  opts,
+}) {
   if (parentEntry !== undefined && entries.length === 1) {
     return
   }
@@ -65,21 +94,26 @@ const iterateChildEntries = function* ({ entries, parentEntry, index, opts }) {
     return
   }
 
-  yield* iterateChildren(childEntries, index, opts)
+  yield* iterateChildren({ childEntries, index, parents, opts })
 }
 
-const iterateChildren = function* (childEntries, index, opts) {
+const iterateChildren = function* ({ childEntries, index, parents, opts }) {
   const nextIndex = index + 1
 
   if (childEntries.length === 1) {
-    yield* iterateLevel(childEntries, nextIndex, opts)
+    yield* iterateLevel({
+      entries: childEntries,
+      index: nextIndex,
+      parents,
+      opts,
+    })
     return
   }
 
   const childEntriesGroups = groupSortChildEntries(childEntries, opts.sort)
 
   // eslint-disable-next-line fp/no-loops
   for (const entries of childEntriesGroups) {
-    yield* iterateLevel(entries, nextIndex, opts)
+    yield* iterateLevel({ entries, index: nextIndex, parents, opts })
   }
 }