Fix dependency error in plan-publish.js

tools/config.js

@@ -31,6 +31,8 @@ export async function getSharedDeps() {
 // Return a list of objects representing the packages to be built. See
 // the function implementation for the full list of keys.
 export async function getPackages() {
+  // The order (shared, lang, config) is important to get dependencies
+  // correct due to poor abstractions in plan-publish.js.
   const packages = [];
   for (const lang of await getSharedDeps()) {
     const type = "shared";

tools/plan-publish.js

@@ -92,8 +92,7 @@ async function planDebianPackages(opts) {
       (await getLangs()).map(async (id) => [id, await readLangConfig(id)])
     )
   );
-  return _.sortBy(
-    await Promise.all(
+  const plan = await Promise.all(
     packages.map(async ({ lang, type, name, buildScriptPath, debPath }) => {
       const desired = crypto
         .createHash("sha1")
@@ -159,13 +158,26 @@ async function planDebianPackages(opts) {
         type,
       };
     })
-    ),
-    ({ type, desired, local, remote }) => {
-      // If *not* a shared package, and all we have to do is download
-      // it, then sort to the end.
-      return type !== "shared" && local !== desired && remote === desired;
-    }
   );
+  const lazilyDownloadedLanguages = new Set();
+  for (const { type, lang, desired, local, remote } of plan) {
+    if (type === "shared") {
+      continue;
+    }
+    // If *not* a shared package, and all we have to do is download
+    // it, then sort to the end. Unless of course this is the lang
+    // package, and we need to rebuild the config package, in which
+    // case the config package (which comes later) will remove that
+    // lang from the set again.
+    if (local !== desired && remote === desired) {
+      lazilyDownloadedLanguages.add(lang);
+    } else {
+      lazilyDownloadedLanguages.delete(lang);
+    }
+  }
+  return _.sortBy(plan, ({ type, lang }) => {
+    return type !== "shared" && lazilyDownloadedLanguages.has(lang);
+  });
 }
 
 async function computePlan() {