Gate V1 protocol behind runtime feature flag by DanGould · Pull Request #1336 · payjoin/rust-payjoin

DanGould · 2026-02-18T14:28:45Z

Summary

Adds a v1 Cargo feature to payjoin-directory that gates all V1 protocol support (fallback endpoint, PSBT screening, database operations, error variants)
Without v1, the directory only supports V2 and returns a version-unsupported BIP78 error for V1 requests
Forwards the feature in payjoin-mailroom as v1 = ["payjoin-directory/v1"]

Stack

This is part of a stacked PR series (merge in order):

Clear V1 payload from memory after first read #1335 - Clear V1 payload from memory after first read
This PR - Gate V1 behind compile-time feature flag
Next: GeoIP region filtering + address blocklist

This PR was developed with AI assistance (Claude)

coveralls · 2026-02-18T14:35:10Z

Pull Request Test Coverage Report for Build 22189613184

Details

86 of 89 (96.63%) changed or added relevant lines in 5 files are covered.
No unchanged relevant lines lost coverage.
Overall coverage increased (+0.1%) to 83.319%

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
payjoin-directory/src/config.rs	0	1	0.0%
payjoin-directory/src/main.rs	0	1	0.0%
payjoin-mailroom/src/config.rs	7	8	87.5%

Totals
Change from base Build 22188799265:	0.1%
Covered Lines:	10344
Relevant Lines:	12415

💛 - Coveralls

spacebear21 · 2026-02-18T23:52:27Z

+                    ScreenResult::ParseError(e) => {
+                        warn!("Could not screen V1 payload: {e}");
+                        // fail-open: unparsable PSBTs can't complete transactions


Shouldn't this return an error response?

Add an `enable_v1` runtime option to both payjoin-directory and payjoin-mailroom that controls whether V1 protocol requests are accepted. Defaults to false (V2-only) and must be explicitly enabled in the operator's configuration. When disabled, V1 POST requests return a `version-unsupported` BIP78 error and V1 PUT responses via OHTTP are silently dropped.

spacebear21

self-ACK on force push: I updated the error response per my earlier review comment and added a commit that tests expected error responses.

benalleng · 2026-02-19T16:21:03Z

+
+    use super::*;
+
+    async fn test_service(enable_v1: bool) -> Service<FilesDb> {


Does this have any value to be pulled out into payjoin-test-utils to be used more generally?

in theory we could move these tests to the payjoin-mailroom which already has a similar utility, but for now I think it's inoffensive enough until payjoin-directory gets folded in

benalleng · 2026-02-19T16:49:30Z

Test plan

* [x]  `cargo test -p payjoin-directory --lib` passes (6 tests, no v1)

* [x]  `cargo test -p payjoin-directory --features v1 --lib` passes (14 tests)

This is beginning to balloon in the misrepresentation of what is happening here.

benalleng

TACK 96b9edc

The code in this PR looks good though claude is definitely misrepresenting what is actually happening in the PR title and description. I assume this happened after some iteration maybe? For our sanity I think that we should clarify what is actually happening as it seemed to properly correct the commit message.

spacebear21 · 2026-02-19T16:53:27Z

I deleted the "test plan" part of the PR description. This is an area where I personally still don't feel comfortable letting the robot write commit messages/PR descriptions. I let it plan and write the code, then review and write commits/descriptions myself.

arminsabouri · 2026-02-19T16:56:22Z

+        if self.enable_v1 {
+            self.post_fallback_v1(id, query, body).await
+        } else {
+            let _ = (id, query, body);


Suggested change

let _ = (id, query, body);

DanGould mentioned this pull request Feb 18, 2026

Add GeoIP region filtering and address blocklist #1337

Merged

DanGould force-pushed the v1-feature-flag branch 3 times, most recently from d71f39a to 1aebe2c Compare February 18, 2026 15:02

spacebear21 force-pushed the v1-feature-flag branch from 13231f2 to 16b9a9c Compare February 18, 2026 23:24

spacebear21 requested changes Feb 19, 2026

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DanGould force-pushed the v1-feature-flag branch 3 times, most recently from 90799c0 to 51198a0 Compare February 19, 2026 08:38

DanGould changed the title ~~Gate V1 protocol behind compile-time feature flag~~ Gate V1 protocol behind runtime feature flag Feb 19, 2026

DanGould requested a review from spacebear21 February 19, 2026 13:25

DanGould force-pushed the v1-feature-flag branch from 51198a0 to 0b08c5d Compare February 19, 2026 13:27

DanGould mentioned this pull request Feb 19, 2026

Add opt-in access control for infrastructure operators #1330

Closed

5 tasks

spacebear21 reviewed Feb 19, 2026

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Comment thread payjoin-directory/src/lib.rs Outdated

DanGould and others added 2 commits February 19, 2026 10:55

Add tests for directory error responses

96b9edc

spacebear21 force-pushed the v1-feature-flag branch from 0b08c5d to 96b9edc Compare February 19, 2026 16:06

spacebear21 approved these changes Feb 19, 2026

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spacebear21 requested a review from benalleng February 19, 2026 16:14

spacebear21 mentioned this pull request Feb 19, 2026

tracking: opt-out of v1 requests on the directory #1198

Open

4 tasks

benalleng reviewed Feb 19, 2026

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benalleng approved these changes Feb 19, 2026

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spacebear21 merged commit 1908139 into payjoin:master Feb 19, 2026
16 checks passed

arminsabouri reviewed Feb 19, 2026

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benalleng mentioned this pull request Feb 19, 2026

Remove ignored v1 fallback code #1345

Merged

2 tasks

DanGould mentioned this pull request Feb 23, 2026

Standup Input: Week of 2026-02-23 #1352

Closed


		use super::*;

		async fn test_service(enable_v1: bool) -> Service<FilesDb> {

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benalleng Feb 19, 2026

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benalleng commented Feb 19, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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spacebear21 commented Feb 19, 2026

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