Initial changes to drop default serde dependency (#255)

Cargo.toml

@@ -22,7 +22,7 @@ default = ["colors"]
 
 # when the redactions feature is enabled values can be redacted in serialized
 # snapshots.
-redactions = ["pest", "pest_derive"]
+redactions = ["pest", "pest_derive", "serialization"]
 
 # Enables support for running filters on snapshot
 filters = ["regex"]
@@ -34,26 +34,39 @@ glob = ["walkdir", "globset"]
 colors = ["console"]
 
 # This feature is now just always enabled because we use yaml internally now.
-serialization = []
+serialization = ["serde"]
 
 # This feature is no longer used as snapshot name detection was changed.
 backtrace = []
 
+# Serialization formats
+# TODO: This could be cleaner by using "dep:csv" without renaming the dep, but
+# this technique allows for a lower MSRV
+csv = ["dep_csv", "serialization"]
+json = ["serde_json", "serialization"]
+ron = ["dep_ron", "serialization"]
+toml = ["dep_toml", "serialization"]
+yaml = ["serde_yaml", "serialization"]
+
 [dependencies]
-csv = { version = "1.1.4", optional = true }
-serde = { version = "1.0.117", features = ["derive"] }
-serde_yaml = "0.8.26"
+dep_csv = { package = "csv", version = "1.1.4", optional = true }
 console = { version = "0.15.1", optional = true, default-features = false }
-serde_json = "1.0.59"
 pest = { version = "2.1.3", optional = true }
 pest_derive = { version = "2.1.0", optional = true }
-ron = { version = "0.7.1", optional = true }
-toml = { version = "0.5.7", optional = true }
+dep_ron = { package = "ron", version = "0.7.1", optional = true }
+dep_toml = { package = "toml", version = "0.5.7", optional = true }
 globset = { version = "0.4.6", optional = true }
 walkdir = { version = "2.3.1", optional = true }
 similar = { version = "2.1.0", features = ["inline"] }
 once_cell = "1.9.0"
 regex = { version = "1.6.0", default-features = false, optional = true, features = ["std", "unicode"] }
+yaml-rust = "0.4.5"
+dep_json = { package = "json", version = "0.12.4" }
+serde = { version = "1.0.117", optional = true }
+serde_json = { version = "1.0.59", optional = true }
+serde_yaml = { version = "0.8.26", optional = true }
+linked-hash-map = "0.5.6"
 
 [dev-dependencies]
+serde = { version = "1.0.117", features = ["derive"] }
 similar-asserts = "1.4.2"

cargo-insta/Cargo.toml

@@ -12,7 +12,7 @@ edition = "2018"
 readme = "README.md"
 
 [dependencies]
-insta = { version = "=1.17.1", path = "..", features = ["redactions"] }
+insta = { version = "=1.17.1", path = "..", features = ["json", "yaml", "redactions"] }
 console = "0.15.1"
 structopt = "0.3.20"
 serde = { version = "1.0.117", features = ["derive"] }

cargo-insta/integration-tests/Cargo.toml

@@ -8,6 +8,6 @@ edition = "2018"
 
 [dependencies]
 dircpy = "0.3.4"
-insta = { version = "1.1.0", path = "../..", features = ["redactions", "glob"] }
+insta = { version = "1.1.0", path = "../..", features = ["json", "yaml", "redactions", "glob"] }
 walkdir = "2.3.1"
 serde = { version = "1.0.117", features = ["derive"] }

src/content/error.rs

@@ -0,0 +1,30 @@
+use std::{error, fmt, result};
+
+use super::Content;
+
+pub type Result<T> = result::Result<T, Error>;
+
+#[derive(Debug)]
+pub enum Error {
+    InvalidStructField(Content),
+    FailedParsingYaml,
+    UnexpectedDataType,
+    MissingField,
+    UnsupportedDataType,
+}
+
+impl fmt::Display for Error {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::InvalidStructField(content) => write!(f, "Invalid struct field: {:?}", content),
+            Self::FailedParsingYaml => f.write_str("Failed parsing the provided YAML text"),
+            Self::UnexpectedDataType => {
+                f.write_str("The present data type wasn't what was expected")
+            }
+            Self::MissingField => f.write_str("A required field was missing"),
+            Self::UnsupportedDataType => f.write_str("Failed converting an unsupported data type"),
+        }
+    }
+}
+
+impl error::Error for Error {}