fix(environment): retain tarball descriptor ownership during export

Use the shared positional reader for both tarball passes so early output refusal cannot close the descriptor ahead of its owner.

Closes #5684

src/application/environment/environmentBundleWrite.test.ts

@@ -1,4 +1,5 @@
 import {
+  appendFile,
   chmod,
   mkdir,
   readFile,
@@ -70,6 +71,58 @@ it("retains the admitted tarball descriptor and refuses a pathname replacement d
   }
 });
 
+it("keeps tarball ownership when the admitted inode grows during output", async () => {
+  const root = await createTestTempDirectory("rea-tarball-growth-");
+  const files = await writeEnvironmentServeFiles(root);
+  const inputs = await readEnvironmentExportInputs(
+    files.manifestPath,
+    files.capturePath,
+  );
+  if (!inputs.ok) throw inputs.error;
+  const tarball = join(root, "package.tgz");
+  await writeFile(tarball, Buffer.alloc(2 * 1024 * 1024, 0x41));
+  const directory = join(root, "bundle");
+  const original = SafeOutputTree.prototype.write;
+  let grown = false;
+  const writer = vi
+    .spyOn(SafeOutputTree.prototype, "write")
+    .mockImplementation(async function (
+      this: SafeOutputTree,
+      ...args: Parameters<SafeOutputTree["write"]>
+    ) {
+      const [relative] = args;
+      if (!grown && relative === "envs/grafana-example/rea-agents.tgz") {
+        grown = true;
+        await appendFile(tarball, Buffer.alloc(1024 * 1024, 0x42));
+      }
+      return original.apply(this, args);
+    });
+  try {
+    const result = await exportEnvironmentBundle({
+      ...inputs.value,
+      source: environmentServeSource(),
+      directory,
+      packageTarball: tarball,
+    });
+    expect(grown).toBe(true);
+    expect(result).toMatchObject({
+      ok: false,
+      error: {
+        _tag: "AnalysisOutputError",
+        operation: "environment-export",
+        reason:
+          "Extracted content exceeds the inventoried size: envs/grafana-example/rea-agents.tgz",
+      },
+    });
+    if (result.ok)
+      throw new Error("Expected the changed tarball to be refused");
+    expect(result.error.cleanup).toBeUndefined();
+    expect(result.error.message).not.toContain("invalidated");
+  } finally {
+    writer.mockRestore();
+  }
+});
+
 it("uses confirmed publication after the output owner's descriptor cleanup completes", async () => {
   const root = await createTestTempDirectory("rea-bundle-published-");
   const files = await writeEnvironmentServeFiles(root);

src/application/environment/environmentBundleWrite.ts

@@ -10,6 +10,7 @@ import {
 import { AnalysisCleanupLease } from "../../artifacts/AnalysisCleanupLease.js";
 import { ArtifactFileCleanupFailure } from "../../artifacts/ArtifactFileOperation.js";
 import { RegularFileCleanupFailure } from "../../filesystem/OwnedRegularFile.js";
+import { readFileHandleChunks } from "../../filesystem/readFileHandleChunks.js";
 import { streamChunkToBuffer } from "../../artifacts/StreamBytes.js";
 import { ArtifactResourceScope } from "../../artifacts/ArtifactResourceScope.js";
 import { SafeOutputTree } from "../../artifacts/SafeOutputTree.js";
@@ -51,10 +52,7 @@ const writeTarball = async (
 ): Promise<WrittenBundleFile> => {
   const hash = createHash("sha256");
   let observed = 0;
-  for await (const chunk of source.handle.createReadStream({
-    start: 0,
-    autoClose: false,
-  })) {
+  for await (const chunk of readFileHandleChunks(source.handle)) {
     const bytes = streamChunkToBuffer(chunk);
     observed += bytes.length;
     if (observed > source.size) throw new RegularFileChangedError(source.path);
@@ -63,7 +61,7 @@ const writeTarball = async (
   if (observed !== source.size) throw new RegularFileChangedError(source.path);
   const written = await tree.write(
     relative,
-    source.handle.createReadStream({ start: 0, autoClose: false }),
+    readFileHandleChunks(source.handle),
     {
       bytes: source.size,
       sha256: hash.digest("hex"),