Change coverage metadata code and remove dependency on serde_json

Cargo.toml

@@ -28,7 +28,6 @@ honggfuzz = { package = "ziggy-honggfuzz-2", version = "0.5.55", optional = true
 libc = { version = "0.2.154", optional = true }
 log = { version = "0.4.21", optional = true }
 semver = { version = "1.0.23", optional = true }
-serde_json = { version = "1.0.116", optional = true }
 strip-ansi-escapes = { version = "0.2.0", optional = true }
 time-humanize = { version = "0.1.3", optional = true }
 toml = { version = "0.8.12", optional = true }
@@ -42,7 +41,6 @@ cli = [
     "toml",
     "semver",
     "anyhow",
-    "serde_json",
     "log",
     "env_logger",
     "strip-ansi-escapes",

src/bin/cargo-ziggy/coverage.rs

@@ -72,21 +72,8 @@ impl Cover {
         let source_or_workspace_root = match &self.source {
             Some(s) => s.display().to_string(),
             None => {
-                // TODO use cargo_metadata
-                let metadata_output = std::process::Command::new("cargo")
-                    .arg("metadata")
-                    .output()
-                    .context("Failed to run cargo metadata")?;
-
-                let stdout =
-                    String::from_utf8(metadata_output.stdout).context("Failed to read stdout")?;
-                let metadata: serde_json::Value =
-                    serde_json::from_str(&stdout).context("Failed to parse JSON")?;
-
-                metadata["workspace_root"]
-                    .as_str()
-                    .context("Failed to get workspace root")?
-                    .to_string()
+                let metadata = cargo_metadata::MetadataCommand::new().exec().unwrap();
+                metadata.workspace_root.into()
             }
         };
 

src/bin/cargo-ziggy/main.rs

@@ -330,6 +330,8 @@ pub fn find_target(target: &String) -> Result<String, anyhow::Error> {
 }
 
 fn guess_target() -> Result<String> {
+    // TODO Use cargo-metadata and remove toml dependency
+
     let cargo_toml_string = fs::read_to_string("Cargo.toml")
         .context("⚠️  couldn't find Cargo.toml in this folder, cannot guess target")?;
     let cargo_toml = cargo_toml_string.parse::<toml::Value>().context(