saphyr-rs/saphyr

Minimal repro: use saphyr::{LoadableYamlNode, Yaml}; fn main() { let document = Yaml::load_from_str(r#""\uD83D\uDE00""#).unwrap(); dbg!(document); } $ cargo run [...] called `Result::unwrap()` on an `Err` value: ScanError { mark: Marker { index: 0, line: 1, col: 0 }, info: "while parsing a quoted scalar, found invalid Unicode character escape code" } Expected: correctly parsed string. Actual: ScanError. Why should surrogate escapes be supported? YAML 1.2 claims to be a superset of JSON (spec): The YAML 1.2 specification was published in 2009. Its primary focus was making YAML a strict superset of JSON. JSON supports surrogate pair escapes (spec): To escape an extended character that is not in the Basic Multilingual Plane, the character is represented as a 12-character sequence, encoding the UTF-16 surrogate pair. So, for example, a string containing only the G clef character (U+1D11E) may be represented as "\uD834\uDD1E". The ultimate result is that JSON can't be par

Summary YamlLoader performs unconditional deep cloning of anchor subtrees when resolving aliases. There is no limit on the number of aliases, the depth of expansion, or the total number of nodes produced. This makes any application that parses untrusted YAML susceptible to a Billion Laughs (alias bomb) attack: a ~100-byte input can produce hundreds of millions of in-memory nodes, exhausting RAM and CPU. Reproduction a: &a ["lol"] b: &b [*a,*a,*a,*a,*a,*a,*a,*a,*a] c: &c [*b,*b,*b,*b,*b,*b,*b,*b,*b] d: &d [*c,*c,*c,*c,*c,*c,*c,*c,*c] e: &e [*d,*d,*d,*d,*d,*d,*d,*d,*d] f: &f [*e,*e,*e,*e,*e,*e,*e,*e,*e] g: &g [*f,*f,*f,*f,*f,*f,*f,*f,*f] h: &h [*g,*g,*g,*g,*g,*g,*g,*g,*g] i: [*h,*h,*h,*h,*h,*h,*h,*h,*h] Parsing this with YamlOwned::load_from_str will attempt to allocate approximately 9^8 (~43 million) String nodes. On most systems this will OOM-kill the process or hang for many seconds before doing so. Root Cause In src/loader.rs, the Event::Alias(id) arm clones the already-expanded subt

Use Case We're looking to migrate zizmor (a security analysis tool for GitHub Actions) from serde_yaml + tree-sitter-yaml to saphyr. The library seems to be a strong fit over the unmaintained serde_yaml crate. However, we are not yet ready for a migration because we need access to comments for parsing zizmor's own directives like # zizmor: ignore[rulename]. Current State Currently, comments are discarded during scanning. In scanner.rs, the skip_to_next_token function skips over comments without preserving them: // scanner.rs lines 861-863 let comment_length = self.input.skip_while_non_breakz(); self.mark.index += comment_length; self.mark.col += comment_length; source Requested Feature We would need the ability to access comments associated with YAML nodes. One approach that seems to fit the existing architecture: Scanner - Tokenize comments instead of discarding them Parser - Emit Event::Comment(Comment) events (fits naturally alongside existing Event::Scalar, Event::MappingStart, et