Merge #11533

11533: Allow opting out of PULUMI_OPTIMIZED_CHECKPOINT_PATCH r=t0yv0 a=t0yv0

<!--- 
Thanks so much for your contribution! If this is your first time contributing, please ensure that you have read the [CONTRIBUTING](https://github.com/pulumi/pulumi/blob/master/CONTRIBUTING.md) documentation.
-->

# Description

<!--- Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context. -->

Fixes # (issue)

## Checklist

<!--- Please provide details if the checkbox below is to be left unchecked. -->
- [ ] I have added tests that prove my fix is effective or that my feature works
<!--- 
User-facing changes require a CHANGELOG entry.
-->
- [ ] I have run `make changelog` and committed the `changelog/pending/<file>` documenting my change
<!--
If the change(s) in this PR is a modification of an existing call to the Pulumi Service,
then the service should honor older versions of the CLI where this change would not exist.
You must then bump the API version in /pkg/backend/httpstate/client/api.go, as well as add
it to the service.
-->
- [ ] Yes, there are changes in this PR that warrants bumping the Pulumi Service API version
  <!-- `@Pulumi` employees: If yes, you must submit corresponding changes in the service repo. -->


Co-authored-by: Anton Tayanovskyy <anton@pulumi.com>

pkg/backend/httpstate/backend.go

@@ -1798,6 +1798,15 @@ func doDetectCapabilities(ctx context.Context, d diag.Sink, client *client.Clien
 		d.Warningf(diag.Message("" /*urn*/, "failed to decode capabilities: %v"), err)
 		return capabilities{}
 	}
+
+	// Allow users to opt out of deltaCheckpointUpdates even if the backend indicates it should be used. This
+	// remains necessary while PULUMI_OPTIMIZED_CHECKPOINT_PATCH has higher memory requirements on the client and
+	// may cause out-of-memory issues in constrained environments.
+	switch strings.ToLower(os.Getenv("PULUMI_OPTIMIZED_CHECKPOINT_PATCH")) {
+	case "0", "false":
+		caps.deltaCheckpointUpdates = nil
+	}
+
 	return caps
 }