Better no-std support and bump esplora-client to 0.4

- Use `default-features = false` for `miniscript` and `bitcoin`
- Introduce `std` & `no-std` features
- Bump `esplora-client` to 0.4

crates/bdk/Cargo.toml

@@ -15,11 +15,11 @@ rust-version = "1.57"
 [dependencies]
 log = "^0.4"
 rand = "^0.8"
-miniscript = { version = "9", features = ["serde"] }
-bitcoin = { version = "0.29", features = ["serde", "base64", "rand"] }
+miniscript = { version = "9", features = ["serde"], default-features = false }
+bitcoin = { version = "0.29", features = ["serde", "base64", "rand"], default-features = false }
 serde = { version = "^1.0", features = ["derive"] }
 serde_json = { version = "^1.0" }
-bdk_chain = { path = "../chain", version = "0.4.0", features = ["miniscript", "serde"] }
+bdk_chain = { path = "../chain", version = "0.4.0", features = ["miniscript", "serde"], default-features = false }
 
 # Optional dependencies
 hwi = { version = "0.5", optional = true, features = [ "use-miniscript"] }
@@ -29,17 +29,15 @@ bip39 = { version = "1.0.1", optional = true }
 getrandom = "0.2"
 js-sys = "0.3"
 
-
 [features]
 default = ["std"]
-std = []
+std = ["bitcoin/std", "miniscript/std", "bdk_chain/std"]
 compiler = ["miniscript/compiler"]
 all-keys = ["keys-bip39"]
 keys-bip39 = ["bip39"]
 hardware-signer = ["hwi"]
 test-hardware-signer = ["hardware-signer"]
 
-
 # This feature is used to run `cargo check` in our CI targeting wasm. It's not recommended
 # for libraries to explicitly include the "getrandom/js" feature, so we only do it when
 # necessary for running our CI. See: https://docs.rs/getrandom/0.2.8/getrandom/#webassembly-support
@@ -52,12 +50,10 @@ env_logger = "0.7"
 base64 = "^0.13"
 assert_matches = "1.5.0"
 
-
 [package.metadata.docs.rs]
 all-features = true
 rustdoc-args = ["--cfg", "docsrs"]
 
-
 [[example]]
 name = "mnemonic_to_descriptors"
 path = "examples/mnemonic_to_descriptors.rs"

crates/chain/Cargo.toml

@@ -13,18 +13,18 @@ readme = "README.md"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-bitcoin = { version = "0.29" }
+bitcoin = { version = "0.29", default-features = false }
 serde_crate = { package = "serde", version = "1", optional = true, features = ["derive"] }
 
 # Use hashbrown as a feature flag to have HashSet and HashMap from it.
 # note version 0.13 breaks outs MSRV.
-hashbrown = { version = "0.12", optional = true,  features = ["serde"] }
-miniscript = { version = "9.0.0", optional = true  }
+hashbrown = { version = "0.12", optional = true, features = ["serde"] }
+miniscript = { version = "9.0.0", optional = true, default-features = false }
 
 [dev-dependencies]
 rand = "0.8"
 
 [features]
-default = ["std", "miniscript"]
-std = []
+default = ["std"]
+std = ["bitcoin/std"]
 serde = ["serde_crate", "bitcoin/serde" ]

crates/esplora/Cargo.toml

@@ -13,7 +13,7 @@ readme = "README.md"
 
 [dependencies]
 bdk_chain = { path = "../chain", version = "0.4.0", features = ["serde", "miniscript"] }
-esplora-client = { version = "0.3", default-features = false }
+esplora-client = { version = "0.4", default-features = false }
 async-trait = { version = "0.1.66", optional = true }
 futures = { version = "0.3.26", optional = true }
 

crates/esplora/src/lib.rs

@@ -14,6 +14,8 @@ mod async_ext;
 #[cfg(feature = "async")]
 pub use async_ext::*;
 
+// this is to avoid warnings when no feature flags are enabled
+#[allow(dead_code)]
 pub(crate) fn map_confirmation_time(
     tx_status: &TxStatus,
     height_at_start: u32,