Is it a bug if builds are not reproducible in CI? How do I debug it?

[ilyagr]

I have the dist/ Vite outputs checked into my repo. I also have a CI check that tests whether the dist/ outputs are up to date: it runs (essentially) npm clean-install && tsc && vite build and checks if the result matches what's in the dir.

(Note for others: Using npm clean-install instead of npm install seems important. pnpm/yarn seem to have a --frozen-lockfile flag, which the former turns on by default in CI)

My problem is that the CI check keeps failing. For example, here are two checks on identical commits. One is from yesterday and passes. One is from today and fails.

Successful: https://github.com/ilyagr/diffedit3/actions/runs/7969138643
Fail: https://github.com/ilyagr/diffedit3/actions/runs/7984527830
The commit in the second run is truly identical to the one in the first run: ilyagr/diffedit3@08477f3

Screenshot of failure. The js file has a new name now:

You can see the entire repo from those links.

Is this normal? How can I debug it?

Thank you!

---

Some background

The reason for my setup is that I intend to make this webapp a part of a much larger Rust program. I would not like people who work on the Rust part of the program to be forced to install Node, even if they don't touch the webapp. Hence, I want to check dist/ into the repo. At the same time, I don't want it to get out of date.

[hi-ogawa]

Did you check this issue? It looks like there are a few workaround suggested there.

• Non-deterministic build #13672

[ilyagr]

Thanks for the suggestion! I will try both workarounds from that thread:

diff --git a/webapp/vite.config.ts b/webapp/vite.config.ts
index 6e39f601ca...c011345ce4 100644
--- a/webapp/vite.config.ts
+++ b/webapp/vite.config.ts
@@ -31,7 +31,13 @@
     }),
   ],
   build: {
+    commonjsOptions: {
+      // https://github.com/vitejs/vite/issues/13672#issuecomment-1784110536
+      strictRequires: true
+    },
     rollupOptions: {
+      // https://github.com/vitejs/vite/issues/10506#issuecomment-1367718113
+      maxParallelFileOps: 1,
       plugins: [
         // externalGlobals() would be nice, but doesn't seem to work
         // externalGlobals({ diff_match_patch: "diff_match_patch" }),

At the moment, it seems to me that the output changes about once a day, and it changes on GitHub a few hours before it changes on my computer. If that is true, it will take me a day or two before I know whether this helped.

[ilyagr]

Yeah, this seems to have helped. I'll reopen this if I see the problem again.