rename filtered_stack_graph to serde

- this new `serde` module will be responsible for defining everything
  related to ser/de in this crate, code from `json` can live in `serde`
  instead
- introduces `crate::serde::Error` for load errors
- adds a minimal test to ensure that accidental merges and inconsistent
  states are unreachable
- turns the `serde` feature flag into an explicit flag

Author: oppiliappan

stack-graphs/Cargo.toml

@@ -14,6 +14,7 @@ edition = "2018"
 
 [features]
 copious-debugging = []
+serde = ["dep:serde", "lsp-positions/serde"]
 json = ["serde", "serde_json", "lsp-positions/serde"]
 
 [lib]
@@ -40,4 +41,4 @@ maplit = "1.0"
 pretty_assertions = "0.7"
 
 [package.metadata.docs.rs]
-all-features = true
+all-features = true

stack-graphs/src/json.rs

@@ -37,9 +37,6 @@ use crate::partial::ScopeStackVariable;
 use crate::partial::SymbolStackVariable;
 use crate::stitching::Database;
 
-#[path = "filtered_stack_graph.rs"]
-mod filtered_stack_graph;
-
 #[derive(Debug, Error)]
 #[error(transparent)]
 pub struct JsonError(#[from] serde_json::error::Error);
@@ -203,6 +200,14 @@ impl<'a> StackGraph {
     pub fn to_json(&'a self, f: &'a dyn Filter) -> JsonStackGraph {
         JsonStackGraph(self, f)
     }
+
+    pub fn to_serializable(&self) -> crate::serde::StackGraph {
+        self.to_serializable_with_filter(&NoFilter)
+    }
+
+    pub fn to_serializable_with_filter(&self, f: &'a dyn Filter) -> crate::serde::StackGraph {
+        crate::serde::StackGraph::from_graph(self, f)
+    }
 }
 
 pub struct JsonStackGraph<'a>(&'a StackGraph, &'a dyn Filter);

stack-graphs/src/lib.rs

@@ -70,6 +70,8 @@ pub mod graph;
 pub mod json;
 pub mod partial;
 pub mod paths;
+#[cfg(feature = "serde")]
+pub mod serde;
 pub mod stitching;
 pub(crate) mod utils;
 #[cfg(feature = "json")]