Add tsp-client compare command.

Author: tjprescott

tools/tsp-client/.gitignore

@@ -3,3 +3,5 @@ node_modules
 dist
 types
 temp
+tsp-output/
+output/

tools/tsp-client/CHANGELOG.md

@@ -5,6 +5,7 @@
 - Added `generate-lock-file` command, see [README](https://github.com/Azure/azure-sdk-tools/blob/main/tools/tsp-client/README.md) for more information.
 - Removed the `--generate-lock-file` flag and replaced it with the command above.
 - Migrated tsp-client from `node:util` to `yargs` for commandline infrastructure.
+- Added `compare` command to compare a hand-authored Swagger to a TypeSpec-generated Swagger to understand the relevant differences between them.
 
 ## 2024-08-05 - 0.10.0
 

tools/tsp-client/src/commands.ts

@@ -284,8 +284,16 @@ export async function generateCommand(argv: any) {
   }
 }
 
-export async function compareCommand(argv: any) {
-  // TODO: Implement
+export async function compareCommand(argv: any, args: string[]) {
+  let outputDir = argv["output-dir"];
+  const openApiDiffPath = await getPathToDependency("openapi-diff");
+  const command = [openApiDiffPath, ...args];
+  try {
+    await nodeCommand(outputDir, command);
+  } catch (err) {
+    Logger.error(`Error occurred while attempting to compare: ${err}`);
+    process.exit(1);
+  }
 }
 
 export async function updateCommand(argv: any) {

tools/tsp-client/src/index.ts

@@ -142,18 +142,6 @@ const parser = yargs(hideBin(process.argv))
       await generateCommand(argv);
     },
   )
-  .command(
-    "compare",
-    "Compare two Swaggers for functional equivalency. This is typically used to compare a source Swagger with a TypeSpec-generated Swagger to ensure that the TypeSpec project is functionally equivalent to the source Swagger.",
-    (yargs: any) => {
-      // FIXME: Add options
-      return yargs;
-    },
-    async (argv: any) => {
-      argv["output-dir"] = resolveOutputDir(argv);
-      await compareCommand(argv);
-    },
-  )
   .command(
     "update",
     "Sync and generate from a TypeSpec project",
@@ -231,6 +219,18 @@ const parser = yargs(hideBin(process.argv))
       await sortSwaggerCommand(argv);
     },
   )
+  .command(
+    "compare",
+    "Compare two Swaggers for functional equivalency. This is typically used to compare a source Swagger with a TypeSpec-generated Swagger to ensure that the TypeSpec project is functionally equivalent to the source Swagger.",
+    (yargs: any) => {
+      return yargs.help(false);
+    },
+    async (argv: any) => {
+      argv["output-dir"] = resolveOutputDir(argv);
+      const rawArgs = process.argv.slice(3);
+      await compareCommand(argv, rawArgs);
+    },
+  )
   .demandCommand(1, "Please provide a command.")
   .help()
   .showHelpOnFail(true);