Inject extension pack dependencies into MRVA packs

If the user requests that extension packs be included in their MRVA run,
then do the following:

1. Search the workspace for all extension packs
2. Add each extension pack as an explicit and direct dependency on
   the generated pack.

It is ok to use `*` as a dependency since we are guaranteed that
exactly one version of each injected extension pack dependency is
available when the pack is being compiled.

If we find multiple paths to an extension pack of the same name, this
is an error since it is ambiguous which path to use.

Author: aeisenberg

extensions/ql-vscode/src/variant-analysis/run-remote-query.ts

@@ -163,6 +163,9 @@ async function createNewQueryPack(
     },
     defaultSuite: generateDefaultSuite(packRelativePath),
   };
+  if (await cliServer.useExtensionPacks()) {
+    injectExtensionPacks(cliServer, syntheticQueryPack, workspaceFolders);
+  }
   await writeFile(
     join(queryPackDir, FALLBACK_QLPACK_FILENAME),
     dump(syntheticQueryPack),
@@ -382,10 +385,36 @@ async function fixPackFile(
   qlpack.name = QUERY_PACK_NAME;
   updateDefaultSuite(qlpack, packRelativePath);
   removeWorkspaceRefs(qlpack);
+  if (await cliServer.useExtensionPacks()) {
+    injectExtensionPacks(cliServer, qlpack, workspaceFolders);
+  }
 
   await writeFile(packPath, dump(qlpack));
 }
 
+function injectExtensionPacks(
+  cliServer: cli.CodeQLCliServer,
+  qlpack: QlPack,
+  workspaceFolders: string[],
+) {
+  const extensionPacks = cliServer.resolveQlpacks(workspaceFolders, true);
+  Object.entries(extensionPacks).forEach(([name, paths]) => {
+    // We are guaranteed that there is at least one path found for each extension pack.
+    // If there are multiple paths, then we have a problem. This means that there is
+    // ambiguity in which path to use. This is an error.
+    if (paths.length > 1) {
+      throw new Error(
+        `Multiple versions of extension pack '${name}' found: ${paths.join(
+          ", ",
+        )}`,
+      );
+    }
+    // Add this extension pack as a dependency. It doesn't matter which
+    // version we specify, since we are guaranteed that the extension pack
+    // is resolved from source at the given path.
+    qlpack.dependencies[name] = "*";
+  });
+}
 
 function updateDefaultSuite(qlpack: QlPack, packRelativePath: string) {
   delete qlpack.defaultSuiteFile;