Organize feature separation for ergonomics (#501)

- first patch closes #393 
- second patch hard-closes #392 hard with an explicit `v1` feature
- make `payjoin/v2` a default feature
- Fix warning for module docs not found with conditional compilation
- Lint previously un-linted v1 payjoin-cli/e2e tests
- Close #499 (Configure v1 checks to use _danger-local-https)

In making these changes I also considered an organizational structure
that looks more like this:

`payjoin::receive::{InputPair, Error...}` `payjoin::v1::receive`,
`payjoin::v2::receive`

But I think that's more trouble than it's worth, and also breaks the
hierarchy that's most effective for producing and maintaining this
software, so I'm inclined to leave it as is, leaving `send`, `receive`
modules abstraction with version-specific submodule implementations.

This makes it easier for us to effectuate #500

contrib/coverage.sh

@@ -3,6 +3,6 @@ set -e
 
 # https://github.com/taiki-e/cargo-llvm-cov?tab=readme-ov-file#merge-coverages-generated-under-different-test-conditions
 cargo llvm-cov clean --workspace # remove artifacts that may affect the coverage results
-cargo llvm-cov --no-report --features=send,receive
-cargo llvm-cov --no-report --features=v2,_danger-local-https,io
+cargo llvm-cov --no-report --no-default-features --features=v1,_danger-local-https
+cargo llvm-cov --no-report --no-default-features --features=v2,_danger-local-https,io
 cargo llvm-cov report --lcov --output-path lcov.info # generate report without tests

contrib/lint.sh

@@ -1,5 +1,5 @@
 #!/usr/bin/env bash
 set -e
 
-cargo clippy --all-targets --keep-going --features=send,receive -- -D warnings
-cargo clippy --all-targets --keep-going --features=v2,_danger-local-https,io -- -D warnings
+cargo clippy --all-targets --keep-going --no-default-features --features=v1,_danger-local-https -- -D warnings
+cargo clippy --all-targets --keep-going --no-default-features --features=v2,_danger-local-https,io -- -D warnings

flake.nix

@@ -88,7 +88,7 @@
                   inherit src;
                 })
           ) {
-            "payjoin" = "--features v2,send,receive";
+            "payjoin" = "--features v2";
             "payjoin-cli" = "--features v1,v2";
             "payjoin-directory" = "";
           };

payjoin-cli/Cargo.toml

@@ -19,10 +19,10 @@ path = "src/main.rs"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 [features]
-default = ["v1"]
+default = ["v2"]
 native-certs = ["reqwest/rustls-tls-native-roots"]
 _danger-local-https = ["rcgen", "reqwest/rustls-tls", "rustls", "hyper-rustls", "payjoin/_danger-local-https", "tokio-rustls"]
-v1 = ["hyper", "hyper-util", "http-body-util"]
+v1 = ["payjoin/v1","hyper", "hyper-util", "http-body-util"]
 v2 = ["payjoin/v2", "payjoin/io"]
 
 [dependencies]
@@ -37,7 +37,7 @@ hyper = { version = "1", features = ["http1", "server"], optional = true }
 hyper-rustls = { version = "0.26", optional = true }
 hyper-util = { version = "0.1", optional = true }
 log = "0.4.7"
-payjoin = { version = "0.22.0", features = ["send", "receive", "base64"] }
+payjoin = { version = "0.22.0", features = ["base64"], default-features = false }
 rcgen = { version = "0.11.1", optional = true }
 reqwest = { version = "0.12", default-features = false }
 rustls = { version = "0.22.4", optional = true }

payjoin-cli/contrib/test.sh

@@ -2,4 +2,4 @@
 set -e
 
 cargo test --locked --package payjoin-cli --verbose --no-default-features --features=_danger-local-https,v2 --test e2e
-cargo test --locked --package payjoin-cli --verbose --features=_danger-local-https
+cargo test --locked --package payjoin-cli --verbose --no-default-features --features=v1,_danger-local-https

payjoin-cli/tests/e2e.rs

@@ -69,13 +69,13 @@ mod e2e {
                 .arg("--rpchost")
                 .arg(&receiver_rpchost)
                 .arg("--cookie-file")
-                .arg(&cookie_file)
+                .arg(cookie_file)
                 .arg("--db-path")
                 .arg(&receiver_db_path_clone)
                 .arg("receive")
                 .arg(RECEIVE_SATS)
                 .arg("--port")
-                .arg(&port.to_string())
+                .arg(port.to_string())
                 .arg("--pj-endpoint")
                 .arg(&pj_endpoint)
                 .stdout(Stdio::piped())
@@ -110,7 +110,7 @@ mod e2e {
                 .arg("--rpchost")
                 .arg(&sender_rpchost)
                 .arg("--cookie-file")
-                .arg(&cookie_file)
+                .arg(cookie_file)
                 .arg("--db-path")
                 .arg(&sender_db_path_clone)
                 .arg("send")

payjoin/Cargo.toml

@@ -16,9 +16,9 @@ exclude = ["tests"]
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [features]
-send = []
-receive = ["bitcoin/rand"]
+default = ["v2"]
 base64 = ["bitcoin/base64"]
+v1 = ["bitcoin/rand"]
 v2 = ["bitcoin/rand", "bitcoin/serde", "hpke", "dep:http", "bhttp", "ohttp", "serde", "url/serde" ]
 #[doc = "Functions to fetch OHTTP keys via CONNECT proxy using reqwest. Enables `v2` since only `v2` uses OHTTP."]
 io = ["v2", "reqwest/rustls-tls"]
@@ -54,4 +54,4 @@ tracing = "0.1.40"
 tracing-subscriber = { version = "0.3.17", features = ["env-filter"] }
 
 [package.metadata.docs.rs]
-features = ["send", "receive", "base64", "v2", "io"]
+features = ["base64", "v2", "io"]

payjoin/src/hpke.rs

@@ -169,7 +169,6 @@ impl<'de> serde::Deserialize<'de> for HpkePublicKey {
 }
 
 /// Message A is sent from the sender to the receiver containing an Original PSBT payload
-#[cfg(feature = "send")]
 pub fn encrypt_message_a(
     body: Vec<u8>,
     reply_pk: &HpkePublicKey,
@@ -192,7 +191,6 @@ pub fn encrypt_message_a(
     Ok(message_a.to_vec())
 }
 
-#[cfg(feature = "receive")]
 pub fn decrypt_message_a(
     message_a: &[u8],
     receiver_sk: HpkeSecretKey,
@@ -223,7 +221,6 @@ pub fn decrypt_message_a(
 }
 
 /// Message B is sent from the receiver to the sender containing a Payjoin PSBT payload or an error
-#[cfg(feature = "receive")]
 pub fn encrypt_message_b(
     mut plaintext: Vec<u8>,
     receiver_keypair: &HpkeKeyPair,
@@ -246,7 +243,6 @@ pub fn encrypt_message_b(
     Ok(message_b.to_vec())
 }
 
-#[cfg(feature = "send")]
 pub fn decrypt_message_b(
     message_b: &[u8],
     receiver_pk: HpkePublicKey,

payjoin/src/lib.rs

@@ -19,10 +19,7 @@
 
 pub extern crate bitcoin;
 
-#[cfg(feature = "receive")]
 pub mod receive;
-
-#[cfg(feature = "send")]
 pub mod send;
 
 #[cfg(feature = "v2")]
@@ -39,11 +36,8 @@ pub(crate) mod bech32;
 #[cfg(feature = "io")]
 pub mod io;
 
-#[cfg(any(feature = "send", feature = "receive"))]
 pub(crate) mod psbt;
-#[cfg(any(feature = "send", all(feature = "receive", feature = "v2")))]
 mod request;
-#[cfg(any(feature = "send", all(feature = "receive", feature = "v2")))]
 pub use request::*;
 
 mod uri;

payjoin/src/send/mod.rs

@@ -2,8 +2,11 @@
 //!
 //! This module contains types and methods used to implement sending via Payjoin.
 //!
-//! For most use cases, it is recommended to start with the [`v2`] module, as it is
-//! backwards compatible and provides the latest features. If you specifically need to use
+//! For most use cases, we recommended enabling the `v2` feature, as it is
+//! backwards compatible and provides the most convenient experience for users and implementors.
+#![cfg_attr(feature = "v2", doc = "To use version 2, refer to [`v2`] module documentation.")]
+//!
+//! If you specifically need to use
 //! version 1, refer to the [`v1`] module documentation.
 
 use std::str::FromStr;

payjoin/tests/integration.rs

@@ -1,4 +1,3 @@
-#[cfg(all(feature = "send", feature = "receive"))]
 mod integration {
     use std::collections::HashMap;
     use std::env;