Should we remove the dependency on tree-sitter-json?

[Xophmeister]

Before dynamic loading was implemented, all supported Tree-sitter grammars were explicit dependencies of Topiary. The move to dynamic loading obviated the need for that, but a few still remain in Cargo.toml for testing purposes. For example, #1022 discusses removing the dependency on tree-sitter-nickel, making the dynamic loading configuration the single source of truth. A similar question can be asked for tree-sitter-json.

tree-sitter-json is only required because it is used in a single doctest:

topiary/topiary-core/src/lib.rs

Lines 184 to 226 in 2d38444

	/// The function that takes an input and formats, or visualises an output.
	///
	/// # Errors
	///
	/// If formatting fails for any reason, a `FormatterError` will be returned.
	///
	/// # Examples
	///
	/// ```
	/// # tokio_test::block_on(async {
	/// use std::fs::File;
	/// use std::io::{BufReader, Read};
	/// use topiary_core::{formatter, Language, FormatterError, TopiaryQuery, Operation};
	///
	/// let input = "[1,2]".to_string();
	/// let mut input = input.as_bytes();
	/// let mut output = Vec::new();
	/// let json = topiary_tree_sitter_facade::Language::from(tree_sitter_json::LANGUAGE);
	///
	/// let mut query_file = BufReader::new(File::open("../topiary-queries/queries/json.scm").expect("query file"));
	/// let mut query_content = String::new();
	/// query_file.read_to_string(&mut query_content).expect("read query file");
	///
	/// let language: Language = Language {
	/// name: "json".to_owned(),
	/// query: TopiaryQuery::new(&json.clone().into(), &query_content).unwrap(),
	/// grammar: json.into(),
	/// indent: None,
	/// };
	///
	/// match formatter(&mut input, &mut output, &language, Operation::Format{ skip_idempotence: false, tolerate_parsing_errors: false }) {
	/// Ok(()) => {
	/// let formatted = String::from_utf8(output).expect("valid utf-8");
	/// }
	/// Err(FormatterError::Query(message, _)) => {
	/// panic!("Error in query file: {message}");
	/// }
	/// Err(_) => {
	/// panic!("An error occurred");
	/// }
	/// }
	/// # }) // end tokio_test
	/// ```

Pro: This doctest is for the main formatter function, so it's an important and valuable example for developers. Rewriting it to use the dynamic loading mechanism may obscure the test, making it less clear and less valuable.

Con: It's a maintenance burden -- albeit a minimal one -- to keep the version of tree-sitter-json aligned in both Cargo.toml and topiary-config/languages.ncl. It's also surprising to see it in Cargo.toml without knowing Topiary's development history.

[Xophmeister]

I've gone ahead and implemented this in #1032