From 03a24a150619f1677133240faef45eec9ec389f9 Mon Sep 17 00:00:00 2001
From: "Steven R. Loomis" <srl295@gmail.com>
Date: Thu, 3 Oct 2024 12:41:08 -0500
Subject: [PATCH] feat(developer): fast-xml-parser: fix for ldml empty
 attributes

- because of the form to="" in ldml, we need to distinguish attributes and sub-elements in the ldml xml parsing
- use an attributePrefix, and fixup the object tree afterwards

Fixes: #12208
---
 .../src/common/web/utils/src/xml-utils.ts     | 42 ++++++++++++-------
 .../xml/tran_fail-matches-nothing-1.xml       | 13 ++++++
 .../xml/tran_fail-matches-nothing-1.xml.json  | 19 +++++++++
 .../common/web/utils/test/test-xml-utils.ts   |  1 +
 4 files changed, 61 insertions(+), 14 deletions(-)
 create mode 100644 developer/src/common/web/utils/test/fixtures/xml/tran_fail-matches-nothing-1.xml
 create mode 100644 developer/src/common/web/utils/test/fixtures/xml/tran_fail-matches-nothing-1.xml.json

diff --git a/developer/src/common/web/utils/src/xml-utils.ts b/developer/src/common/web/utils/src/xml-utils.ts
index 02d28dfc90c..9ed252256e6 100644
--- a/developer/src/common/web/utils/src/xml-utils.ts
+++ b/developer/src/common/web/utils/src/xml-utils.ts
@@ -25,7 +25,7 @@ type KemanXMLOptionsBag = {
 const PARSER_OPTIONS: KemanXMLOptionsBag = {
   'keyboard3': {
     ignoreAttributes: false, // We'd like attributes, please
-    attributeNamePrefix: '', // to avoid '@_' prefixes
+    attributeNamePrefix: '@__', // We'll use this to convert attributes to strings and subobjects to arrays, when empty.
     trimValues: false, // preserve spaces, but:
     htmlEntities: true,
     tagValueProcessor: (tagName: string, tagValue: string /*, jPath, hasAttributes, isLeafNode*/) => {
@@ -133,19 +133,35 @@ export class KeymanXMLReader {
     }
   }
 
-  /** replace any empty string "" with an empty object {} */
+  /**
+   * Requires attribute prefix @__ (double underscore)
+   * For attributes, just remove @__ and continue.
+   * For objects, replace any empty string "" with an empty object {} */
   private static fixupEmptyStringToEmptyObject(data: any) : any {
-    if (data === "") {
-      // this is the core feature here.
-      return {};
-    } else if (typeof data === 'object') {
+    if (typeof data === 'object') {
+      // For arrays of objects, we map "" to {}
+      // "" means an empty object
       if (Array.isArray(data)) {
-        return data.map(v => KeymanXMLReader.fixupEmptyStringToEmptyObject(v));
+        return data.map(v => {
+          if (v === '') {
+            return {};
+          } else {
+            return KeymanXMLReader.fixupEmptyStringToEmptyObject(v);
+          }
+        });
       }
-      // object
-      const e : any = [];
+      // otherwise: remove @__ for attributes, remap objects
+      const e: any = [];
       Object.entries(data).forEach(([k, v]) => {
-        e.push([k, KeymanXMLReader.fixupEmptyStringToEmptyObject(v)]);
+        if (k.startsWith('@__')) {
+          e.push([k.substring(3), KeymanXMLReader.fixupEmptyStringToEmptyObject(v)]);
+        } else {
+          if (v === '') {
+            e.push([k, {}]);
+          } else {
+            e.push([k, KeymanXMLReader.fixupEmptyStringToEmptyObject(v)]);
+          }
+        }
       });
       return Object.fromEntries(e);
     } else {
@@ -217,11 +233,9 @@ export class KeymanXMLReader {
     let result = parser.parse(data, true);
     if (PARSER_OPTIONS[this.type].attributeNamePrefix === '$') {
       result = KeymanXMLReader.fixupDollarAttributes(result);
-    }
-    if (this.type === 'keyboard3') {
+    } else if (PARSER_OPTIONS[this.type].attributeNamePrefix === '@__') {
       result = KeymanXMLReader.fixupEmptyStringToEmptyObject(result);
-    }
-    if (PARSER_OPTIONS[this.type].preserveOrder) {
+    } else if (PARSER_OPTIONS[this.type].preserveOrder) {
       result = KeymanXMLReader.fixupPreserveOrder(result);
     }
     delete result['?xml'];
diff --git a/developer/src/common/web/utils/test/fixtures/xml/tran_fail-matches-nothing-1.xml b/developer/src/common/web/utils/test/fixtures/xml/tran_fail-matches-nothing-1.xml
new file mode 100644
index 00000000000..5b5e2bba5bd
--- /dev/null
+++ b/developer/src/common/web/utils/test/fixtures/xml/tran_fail-matches-nothing-1.xml
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<keyboard3 conformsTo="45" xmlns="https://schemas.unicode.org/cldr/45/keyboard3" locale="mt" >
+  <info name="fail-matches-nothing"/>
+
+  <keys />
+
+  <transforms type="simple">
+    <transformGroup>
+      <transform from=""/>
+    </transformGroup>
+  </transforms>
+</keyboard3>
diff --git a/developer/src/common/web/utils/test/fixtures/xml/tran_fail-matches-nothing-1.xml.json b/developer/src/common/web/utils/test/fixtures/xml/tran_fail-matches-nothing-1.xml.json
new file mode 100644
index 00000000000..477499477d8
--- /dev/null
+++ b/developer/src/common/web/utils/test/fixtures/xml/tran_fail-matches-nothing-1.xml.json
@@ -0,0 +1,19 @@
+{
+ "keyboard3": {
+  "conformsTo": "45",
+  "xmlns": "https://schemas.unicode.org/cldr/45/keyboard3",
+  "locale": "mt",
+  "info": {
+   "name": "fail-matches-nothing"
+  },
+  "keys": {},
+  "transforms": {
+   "type": "simple",
+   "transformGroup": {
+    "transform": {
+     "from": ""
+    }
+   }
+  }
+ }
+}
\ No newline at end of file
diff --git a/developer/src/common/web/utils/test/test-xml-utils.ts b/developer/src/common/web/utils/test/test-xml-utils.ts
index fbe32f8da4f..1cc9724b278 100644
--- a/developer/src/common/web/utils/test/test-xml-utils.ts
+++ b/developer/src/common/web/utils/test/test-xml-utils.ts
@@ -32,6 +32,7 @@ const read_cases: Case[] = [
       'k_020_fr.xml',
       'strs_invalid-illegal.xml',
       'tran_fail-empty.xml',
+      'tran_fail-matches-nothing-1.xml',
     ],
   }, {
     type: 'keyboardTest3',