fix: Various compilation issues

Ref: #356 #358

CHANGELOG.md

@@ -2,6 +2,15 @@
 
 ## [Unreleased]
 
+### Fixed
+
+- Library compilation with no default features. [#356](https://github.com/Stranger6667/jsonschema-rs/issues/356)
+- Compilation with `resolve-file` only. [#358](https://github.com/Stranger6667/jsonschema-rs/issues/358)
+
+### Changed
+
+- **BREAKING**: Revert changes from [#353](https://github.com/Stranger6667/jsonschema-rs/issues/353) and [#343](https://github.com/Stranger6667/jsonschema-rs/issues/343), as they caused compilation issues.
+
 ## [0.15.2] - 2022-04-10
 
 ### Fixed

README.md

@@ -23,9 +23,6 @@ Partially supported drafts (some keywords are not implemented):
 jsonschema = "0.15"
 ```
 
-By default `jsonschema` resolves remote references via HTTP by using `reqwest` with `native-tls`.
-If you'd like to use `rustls`, you have to explicitly enable `reqwest` and `rustls` features and disable `native-tls` via `default-features = false` in your `Cargo.toml` file.
-
 To validate documents against some schema and get validation errors (if any):
 
 ```rust
@@ -121,6 +118,17 @@ fn main() {
 }
 ```
 
+## Reference resolving and TLS
+
+By default, `jsonschema` resolves HTTP references via `reqwest` without TLS support.
+If you'd like to resolve HTTPS, you need to enable TLS support in `reqwest`:
+
+```toml
+reqwest = { version = "*", features = [ "rustls-tls" ] }
+```
+
+Otherwise, you might get validation errors like `invalid URL, scheme is not http`.
+
 ## Status
 
 This library is functional and ready for use, but its API is still evolving to the 1.0 API.

jsonschema/Cargo.toml

@@ -21,12 +21,9 @@ default = ["resolve-http", "resolve-file", "cli"]
 draft201909 = []
 draft202012 = []
 
-resolve-http = ["reqwest", "native-tls"]
+resolve-http = ["reqwest"]
 resolve-file = []
 
-native-tls = ["reqwest/default-tls"]
-rustls = ["reqwest/rustls-tls"]
-
 [dependencies]
 ahash = { version = "0.7.6", features = ["serde"] }
 anyhow = "1.0.55"
@@ -42,7 +39,7 @@ num-cmp = "0.1.0"
 parking_lot = "0.12.0"
 percent-encoding = "2.1.0"
 regex = "1.5.4"
-reqwest = { package = "reqwest", version = "0.11.9", features = ["blocking", "json"], default-features = false, optional = true }
+reqwest = { version = "0.11.9", features = ["blocking", "json"], default-features = false, optional = true }
 serde = { version = "1.0.136", features = ["derive"] }
 serde_json = "1.0.79"
 structopt = { version = "0.3.26", optional = true }

jsonschema/src/resolver.rs

@@ -76,30 +76,17 @@ impl SchemaResolver for DefaultResolver {
     ) -> Result<Arc<Value>, SchemaResolverError> {
         match url.scheme() {
             "http" | "https" => {
-                #[cfg(not(any(
-                    feature = "resolve-http",
-                    all(feature = "reqwest", feature = "rustls"),
-                    test
-                )))]
+                #[cfg(all(feature = "reqwest", not(feature = "resolve-http")))]
                 {
-                    compile_error!(
-                        r#"the `reqwest` feature alone does not enable HTTP schema resolving anymore.
-Use the `resolve-http` feature which enables `native-tls` as well;
-or both `reqwest` and `rustls` features together, if you prefer rustls."#
-                    );
+                    compile_error!("the `reqwest` feature does not enable HTTP schema resolving anymore, use the `resolve-http` feature instead");
                 }
-
-                #[cfg(any(
-                    feature = "resolve-http",
-                    all(feature = "reqwest", feature = "rustls"),
-                    test
-                ))]
+                #[cfg(any(feature = "resolve-http", test))]
                 {
                     let response = reqwest::blocking::get(url.as_str())?;
                     let document: Value = response.json()?;
                     Ok(Arc::new(document))
                 }
-                #[cfg(not(any(feature = "resolve-http", all(feature="reqwest", feature="rustls"), test)))]
+                #[cfg(not(any(feature = "resolve-http", test)))]
                 Err(anyhow::anyhow!("`resolve-http` feature or a custom resolver is required to resolve external schemas via HTTP"))
             }
             "file" => {