feat(data-mapper-v2): Make XSLT the source of truth for map definitions

This change fundamentally shifts how Data Mapper v2 stores and loads maps:

**Core Changes:**
- XSLT is now the authoritative source for map definitions
- Added XsltParser to extract map definitions from XSLT text value templates
- Added XsltMetadataSerializer for v3 metadata format (UI layout only)
- Removed LML embedding in XSLT comments (v2 format deprecated)

**XPath to LML Conversion:**
- Convert single-quoted string literals to double quotes for LML compatibility
- Convert XPath infix math operators (+, -, *, div, mod) to function calls
- Remove namespace prefixes (math:, xs:, etc.) from function names
- Flatten associative operators (+, *) to multi-argument function calls

**Bug Fixes:**
- Fix delete button not working for custom values in unbounded inputs
- Fix node position changes not triggering dirty state (Save button)

**VS Code Extension:**
- Update file service to use XSLT content directly
- Add commands for loading/saving XSLT content

Author: hartra344

Localize/lang/strings.json

@@ -3810,6 +3810,7 @@
   "_qJpnIL.comment": "Label for description of custom endsWith Function",
   "_qKVOwV.comment": "Placeholder text for the MCP server name field",
   "_qMFpNH.comment": "Loading dynamic data",
+  "_qNy7WP.comment": "Message to display when XSLT content hasn't been generated yet",
   "_qSejoi.comment": "Label for description of custom lessOrEquals Function",
   "_qSt0Sb.comment": "Accessibility prefix for the input label",
   "_qUWBUX.comment": "A duration of time shown in days",
@@ -4097,7 +4098,7 @@
   "_wQcEXt.comment": "Required parameters for the custom Replace Function",
   "_wQsEwc.comment": "Required length parameter to obtain substring",
   "_wT/gMB.comment": "Description for featured connectors field",
-  "_wTaSTp.comment": "Tooltip for disabled test button",
+  "_wTaSTp.comment": "Message when XSLT content is not available",
   "_wV3Lmd.comment": "Label to delete dictionary item",
   "_wWVQuK.comment": "Label for description of custom if Function",
   "_wWuzqz.comment": "Ok button text",
@@ -4919,6 +4920,7 @@
   "qJpnIL": "Checks if the string ends with a value (case-insensitive, invariant culture)",
   "qKVOwV": "Enter a name for the MCP server",
   "qMFpNH": "Loading dynamic data",
+  "qNy7WP": "XSLT not yet generated. Save the map to generate XSLT output.",
   "qSejoi": "Returns true if the first argument is less than or equal to the second",
   "qSt0Sb": "Required",
   "qUWBUX": "{days, plural, one {# day} other {# days}}",

apps/vs-code-designer/package.json

@@ -42,12 +42,14 @@
     "process-tree": "^1.0.3",
     "ps-tree": "^1.2.0",
     "recursive-copy": "^2.0.14",
+    "saxon-js": "^2.6.0",
     "semver": "^6.3.1",
     "tslib": "2.4.0",
     "uuid": "^10.0.0",
     "vscode-extension-tester": "^8.17.0",
     "vscode-nls": "^5.2.0",
     "xml2js": "0.6.2",
+    "xslt3": "^2.7.0",
     "yaml": "^2.7.0",
     "yaml-types": "^0.4.0",
     "yargs-parser": "21.1.1",

apps/vs-code-designer/src/app/commands/dataMapper/DataMapperExt.ts

@@ -15,6 +15,63 @@ import { parse } from 'yaml';
 import { localize } from '../../../localize';
 import { assetsFolderName, dataMapNameValidation } from '../../../constants';
 
+/**
+ * UI metadata for function positions and canvas state.
+ */
+interface XsltUiMetadata {
+  functionNodes: Array<{
+    reactFlowGuid: string;
+    functionKey: string;
+    position: { x: number; y: number };
+    connections: Array<{ name: string; inputOrder: number }>;
+    connectionShorthand: string;
+  }>;
+  canvasRect?: { x: number; y: number; width: number; height: number };
+}
+
+/**
+ * Metadata embedded in XSLT files for Data Mapper v2.
+ * Contains mapDefinition in the metadata (legacy format).
+ * @deprecated Use XsltMapMetadataV3 which doesn't embed mapDefinition
+ */
+interface XsltMapMetadataV2 {
+  version: '2.0';
+  sourceSchema: string;
+  targetSchema: string;
+  mapDefinition: MapDefinitionEntry;
+  metadata: XsltUiMetadata;
+}
+
+/**
+ * Metadata embedded in XSLT files for Data Mapper v3.
+ * Only embeds layout metadata - mapping logic is derived from XSLT content.
+ */
+interface XsltMapMetadataV3 {
+  version: '3.0';
+  sourceSchema: string;
+  targetSchema: string;
+  metadata: XsltUiMetadata;
+}
+
+/**
+ * Union type supporting both v2 and v3 metadata formats.
+ */
+type XsltMapMetadata = XsltMapMetadataV2 | XsltMapMetadataV3;
+
+/**
+ * Type guard to check if metadata is v2 format (with mapDefinition).
+ */
+const isV2Metadata = (metadata: XsltMapMetadata): metadata is XsltMapMetadataV2 => {
+  return metadata.version === '2.0' && 'mapDefinition' in metadata;
+};
+
+/**
+ * Type guard to check if metadata is v3 format (without mapDefinition).
+ */
+const isV3Metadata = (metadata: XsltMapMetadata): metadata is XsltMapMetadataV3 => {
+  return metadata.version === '3.0';
+};
+
 export default class DataMapperExt {
   public static async openDataMapperPanel(
     context: IActionContext,
@@ -119,4 +176,101 @@ export default class DataMapperExt {
       }
     }
   }
+
+  /**
+   * Regex to extract metadata JSON from XSLT comment.
+   */
+  private static readonly METADATA_REGEX = /<!--\s*LogicAppsDataMapper:\s*([\s\S]*?)\s*-->/;
+
+  /**
+   * Checks if an XSLT string has embedded metadata.
+   */
+  public static hasEmbeddedMetadata(xslt: string): boolean {
+    return DataMapperExt.METADATA_REGEX.test(xslt);
+  }
+
+  /**
+   * Extracts metadata from an XSLT string if present.
+   * Supports both v2 (with mapDefinition) and v3 (without mapDefinition) formats.
+   */
+  public static extractMetadataFromXslt(xslt: string): XsltMapMetadata | null {
+    const match = xslt.match(DataMapperExt.METADATA_REGEX);
+
+    if (!match || !match[1]) {
+      return null;
+    }
+
+    try {
+      const metadata = JSON.parse(match[1]) as XsltMapMetadata;
+
+      // Validate required fields (common to both v2 and v3)
+      if (!metadata.version || !metadata.sourceSchema || !metadata.targetSchema) {
+        console.warn('XSLT metadata missing required fields');
+        return null;
+      }
+
+      // v2 requires mapDefinition, v3 does not
+      if (metadata.version === '2.0' && !('mapDefinition' in metadata)) {
+        console.warn('XSLT metadata v2.0 missing mapDefinition');
+        return null;
+      }
+
+      return metadata;
+    } catch (error) {
+      console.error('Failed to parse XSLT metadata JSON:', error);
+      return null;
+    }
+  }
+
+  /**
+   * Return type for loadMapFromXslt
+   */
+  public static loadMapFromXslt(
+    xsltContent: string,
+    _extInstance: typeof ext
+  ): {
+    mapDefinition: MapDefinitionEntry;
+    sourceSchemaFileName: string;
+    targetSchemaFileName: string;
+    metadata?: XsltUiMetadata;
+    xsltContent?: string;
+    isV3Format?: boolean;
+  } | null {
+    const metadata = DataMapperExt.extractMetadataFromXslt(xsltContent);
+
+    if (!metadata) {
+      return null;
+    }
+
+    // Handle v2 format (with embedded mapDefinition)
+    if (isV2Metadata(metadata)) {
+      // Fix custom values in the map definition (same processing as LML)
+      DataMapperExt.fixMapDefinitionCustomValues(metadata.mapDefinition);
+
+      return {
+        mapDefinition: metadata.mapDefinition,
+        sourceSchemaFileName: metadata.sourceSchema,
+        targetSchemaFileName: metadata.targetSchema,
+        metadata: metadata.metadata,
+        isV3Format: false,
+      };
+    }
+
+    // Handle v3 format (without embedded mapDefinition)
+    // For v3, we pass the raw XSLT content so the webview can parse it
+    // to derive the mapping connections from the actual XSLT
+    if (isV3Metadata(metadata)) {
+      return {
+        // Empty mapDefinition - webview will derive from XSLT
+        mapDefinition: {},
+        sourceSchemaFileName: metadata.sourceSchema,
+        targetSchemaFileName: metadata.targetSchema,
+        metadata: metadata.metadata,
+        xsltContent: xsltContent,
+        isV3Format: true,
+      };
+    }
+
+    return null;
+  }
 }