Fix incomplete render when --mode is used

src/generate.ts

@@ -10,6 +10,7 @@ import {
   Cache,
   execUtils,
   hashUtils,
+  InstallMode,
   LocatorHash,
   Package,
   Project,
@@ -22,8 +23,12 @@ import projectExprTmpl from "./tmpl/yarn-project.nix.in";
 import { tmpdir } from "os";
 
 // Generator function that runs after `yarn install`.
-export default async (project: Project, cache: Cache, report: Report) => {
+export default async (
+  project: Project,
+  opts: { cache: Cache; report: Report; mode?: InstallMode }
+) => {
   const { configuration, cwd } = project;
+  const { cache, report } = opts;
 
   // This case happens with `yarn dlx`, for example, and may cause errors if
   // special settings don't apply to those installations. (Like a `nixExprPath`
@@ -267,6 +272,11 @@ export default async (project: Project, cache: Cache, report: Report) => {
   }
 
   // Render the Nix expression.
+  //
+  // If isolated builds are used, we rely on the build state, so don't render
+  // if a special `--mode` was specified. This is because skipping builds may
+  // give us an incomplete build state.
+  if (opts.mode == null || isolatedBuilds.length === 0) {
     const ident = project.topLevelWorkspace.manifest.name;
     const projectName = ident ? structUtils.stringifyIdent(ident) : `workspace`;
     const projectExpr = renderTmpl(projectExprTmpl, {
@@ -293,6 +303,7 @@ export default async (project: Project, cache: Cache, report: Report) => {
         );
       }
     }
+  }
 
   // Preload the cache entries into the Nix store.
   if (

src/index.ts

@@ -25,7 +25,7 @@ const plugin: Plugin<Hooks> = {
         opts.persistProject !== false &&
         project.configuration.get(`enableNixify`)
       ) {
-        await generate(project, opts.cache, opts.report);
+        await generate(project, opts);
       }
     },
   },