Replace serde-yaml with serde-saphyr (again) by j178 · Pull Request #1520 · j178/prek

j178 · 2026-02-01T13:00:10Z

serde-saphyr has way better error message, and it is written in safe Rust.

Previous try: #1087
Previous revert: #1106 and #1112

TODO:
Replace serialize_yaml_scalar with serde-saphyr as well:

Lines 12 to 13 in 0a4be22

    
           /// Serialize a YAML scalar while preserving the caller's quote style. 
        
           pub(crate) fn serialize_yaml_scalar(value: &str, quote: &str) -> Result<String> {

codecov · 2026-02-01T13:02:47Z

Codecov Report

❌ Patch coverage is 98.59155% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.93%. Comparing base (0a4be22) to head (6b2b8bc).
⚠️ Report is 6 commits behind head on master.

Files with missing lines	Patch %	Lines
...ates/prek/src/hooks/pre_commit_hooks/check_yaml.rs	86.66%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1520      +/-   ##
==========================================
- Coverage   92.02%   91.93%   -0.09%     
==========================================
  Files          89       89              
  Lines       18500    18288     -212     
==========================================
- Hits        17024    16813     -211     
+ Misses       1476     1475       -1

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serde-saphyr has way better error message, and it is written in safe Rust.

prek-ci-bot · 2026-02-01T13:07:49Z

📦 Cargo Bloat Comparison

Binary size change: +3.10% (22.6 MiB → 23.3 MiB)

Expand for cargo-bloat output

Head Branch Results

 File  .text    Size             Crate Name
 0.3%   0.8% 75.6KiB             prek? <prek::cli::Command as clap_builder::derive::Subcommand>::augment_subcommands
 0.3%   0.7% 70.3KiB              prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.3%   0.7% 65.1KiB              prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.2%   0.5% 51.2KiB annotate_snippets annotate_snippets::renderer::render::render
 0.2%   0.5% 50.8KiB              prek prek::languages::<impl prek::config::Language>::install::{{closure}}
 0.2%   0.4% 43.4KiB              prek prek::identify::by_extension::{{closure}}
 0.2%   0.4% 43.3KiB              prek prek::run::{{closure}}
 0.2%   0.4% 41.7KiB              prek prek::cli::run::run::run::{{closure}}
 0.1%   0.3% 31.7KiB             prek? <prek::cli::RunArgs as clap_builder::derive::Args>::augment_args
 0.1%   0.3% 28.4KiB      serde_saphyr saphyr_parser_bw::scanner::Scanner<T>::fetch_more_tokens
 0.1%   0.3% 24.8KiB             prek? <prek::config::_::<impl serde_core::de::Deserialize for prek::config::Config>::deserialize::__Visitor as serde_core::de::Visitor>::visit_map
 0.1%   0.2% 22.6KiB      serde_saphyr saphyr_parser_bw::scanner::Scanner<T>::fetch_more_tokens
 0.1%   0.2% 22.1KiB              prek prek::hooks::meta_hooks::MetaHooks::run::{{closure}}
 0.1%   0.2% 21.2KiB      clap_builder clap_builder::parser::parser::Parser::get_matches_with
 0.1%   0.2% 20.0KiB   cargo_metadata? <cargo_metadata::_::<impl serde_core::de::Deserialize for cargo_metadata::Package>::deserialize::__Visitor as serde_core::de::Visitor>::visit_map
 0.1%   0.2% 19.8KiB              prek prek::archive::unzip::{{closure}}
 0.1%   0.2% 19.7KiB              prek prek::hooks::meta_hooks::MetaHooks::run::{{closure}}
 0.1%   0.2% 19.5KiB              prek prek::cli::run::filter::collect_files_from_args::{{closure}}
 0.1%   0.2% 19.3KiB               std core::ptr::drop_in_place<prek::languages::<impl prek::config::Language>::install::{{closure}}>
 0.1%   0.2% 19.3KiB              prek <prek::languages::ruby::ruby::Ruby as prek::languages::LanguageImpl>::install::{{closure}}
37.9%  91.3%  8.8MiB                   And 20592 smaller methods. Use -n N to show more.
41.5% 100.0%  9.7MiB                   .text section size, the file size is 23.3MiB

Base Branch Results

 File  .text    Size           Crate Name
 0.3%   0.8% 77.0KiB           prek? <prek::cli::Command as clap_builder::derive::Subcommand>::augment_subcommands
 0.3%   0.8% 70.3KiB            prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.3%   0.7% 65.1KiB            prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.2%   0.5% 50.8KiB            prek prek::languages::<impl prek::config::Language>::install::{{closure}}
 0.2%   0.5% 43.9KiB            prek prek::run::{{closure}}
 0.2%   0.5% 43.4KiB            prek prek::identify::by_extension::{{closure}}
 0.2%   0.4% 41.5KiB            prek prek::cli::run::run::run::{{closure}}
 0.1%   0.3% 32.0KiB           prek? <prek::cli::RunArgs as clap_builder::derive::Args>::augment_args
 0.1%   0.2% 22.1KiB            prek prek::hooks::meta_hooks::MetaHooks::run::{{closure}}
 0.1%   0.2% 22.1KiB            prek prek::hooks::meta_hooks::MetaHooks::run::{{closure}}
 0.1%   0.2% 21.2KiB    clap_builder clap_builder::parser::parser::Parser::get_matches_with
 0.1%   0.2% 20.0KiB cargo_metadata? <cargo_metadata::_::<impl serde_core::de::Deserialize for cargo_metadata::Package>::deserialize::__Visitor as serde_core::de::Visitor>::visit_map
 0.1%   0.2% 19.6KiB            prek prek::archive::unzip::{{closure}}
 0.1%   0.2% 19.5KiB            prek prek::cli::run::filter::collect_files_from_args::{{closure}}
 0.1%   0.2% 19.3KiB             std core::ptr::drop_in_place<prek::languages::<impl prek::config::Language>::install::{{closure}}>
 0.1%   0.2% 19.3KiB            prek <prek::languages::ruby::ruby::Ruby as prek::languages::LanguageImpl>::install::{{closure}}
 0.1%   0.2% 19.1KiB            prek prek::cli::run::filter::collect_files_from_args::{{closure}}
 0.1%   0.2% 18.6KiB            ring ring_core_0_17_14__x25519_ge_frombytes_vartime
 0.1%   0.2% 18.1KiB       [Unknown] fe_loose_invert
 0.1%   0.2% 18.1KiB      hyper_util hyper_util::client::legacy::client::Client<C,B>::send_request::{{closure}}
36.8%  91.3%  8.3MiB                 And 20083 smaller methods. Use -n N to show more.
40.3% 100.0%  9.1MiB                 .text section size, the file size is 22.6MiB

crates/prek/src/config.rs

Copilot

Pull request overview

This PR switches prek’s YAML parsing from serde_yaml to serde-saphyr to improve user-facing YAML error messages (including richer spans/snippets), and updates tests/schema accordingly.

Changes:

Replace serde_yaml with serde-saphyr for config/manifest parsing and the check-yaml builtin hook.
Update integration/unit test snapshots to match the new error formatting.
Regenerate/update prek.schema.json and dependency manifests/lockfile for the new YAML stack.

Reviewed changes

Copilot reviewed 14 out of 15 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
prek.schema.json	Regenerated schema reflecting updated config model/serialization details.
crates/prek/src/config.rs	Switch config/manifest parsing to `serde-saphyr` and update related unit tests/snapshots.
crates/prek/src/hooks/pre_commit_hooks/check_yaml.rs	Use `serde-saphyr` to validate YAML files (single/multi-doc) and adjust error output.
crates/prek/src/yaml.rs	Remove prior merge-key processing code, leaving scalar serialization logic.
crates/prek/src/cli/run/filter.rs	Update tests to construct glob patterns without `serde_yaml`.
crates/prek/tests/workspace.rs	Snapshot updates for new YAML parse errors.
crates/prek/tests/validate.rs	Snapshot updates + new test coverage for invalid-config errors with new formatting.
crates/prek/tests/run.rs	Snapshot updates for new YAML parse errors.
crates/prek/tests/meta_hooks.rs	Snapshot updates for new YAML parse errors.
crates/prek/tests/install.rs	Snapshot updates for new YAML parse errors in warnings.
crates/prek/tests/builtin_hooks.rs	Snapshot updates for `check-yaml` output + naming tweaks in test display strings.
crates/prek/tests/auto_update.rs	Snapshot updates for new YAML parse errors.
crates/prek/Cargo.toml	Swap dependency from `serde_yaml` to `serde-saphyr`.
Cargo.toml	Add workspace dependency for `serde-saphyr` and adjust clippy lint settings.
Cargo.lock	Lockfile updates for `serde-saphyr` and its transitive dependencies.

Copilot · 2026-02-02T12:28:08Z

crates/prek/src/hooks/pre_commit_hooks/check_yaml.rs

+    let options = serde_saphyr::Options {
+        ignore_binary_tag_for_string: true,
+        ..Default::default()
+    };
    if allow_multi_docs {
-        for doc in deserializer {
-            if let Err(e) = serde_yaml::Value::deserialize(doc) {
-                let error_message =
-                    format!("{}: Failed to yaml decode ({e})\n", filename.display());
-                return Ok((1, error_message.into_bytes()));
-            }
+        if let Err(e) = serde_saphyr::from_slice_multiple_with_options::<serde_json::Value>(
+            &content,
+            options.clone(),
+        ) {
+            let error_message = format!("{}: Failed to yaml decode ({e})\n", filename.display());
+            return Ok((1, error_message.into_bytes()));
        }
        Ok((0, Vec::new()))
    } else {
-        match serde_yaml::from_slice::<serde_yaml::Value>(&content) {
+        match serde_saphyr::from_slice_with_options::<serde_json::Value>(&content, options) {
            Ok(_) => Ok((0, Vec::new())),


check-yaml now deserializes YAML into serde_json::Value, which only supports JSON-compatible YAML (e.g., mapping keys must be strings). This can cause valid YAML files (such as those with non-string keys or other YAML-only constructs) to be reported as invalid. Consider parsing/deserializing into a YAML value type (or using a parser-only API) so this hook validates YAML syntax rather than JSON compatibility.

Copilot · 2026-02-02T12:28:09Z

crates/prek/src/config.rs

+    let config = serde_saphyr::from_str(&content)
+        .map_err(|e| Error::Yaml(path.user_display().to_string(), Box::new(e)))?;


The serde_saphyr error string already includes a leading "error:"; wrapping it as the source for Failed to parse ... results in user output like "caused by: error: ..." / "Failed to parse ...: error: ...". Consider normalizing the source message (e.g., stripping the leading prefix) before boxing/storing it so the final output isn’t redundant.

crates/prek/src/config.rs

Copilot · 2026-02-02T12:28:09Z

prek.schema.json

+          },
+          "writeOnly": true


writeOnly: true on RemoteRepo.hooks is likely incorrect for a configuration-file JSON schema (it may hide the property in editors/UI tooling even though it’s required for configs). Consider removing writeOnly here unless there’s a specific schema-consumer reason for it.

Suggested change

},

"writeOnly": true

}

j178 added the enhancement New feature or request label Feb 1, 2026

Replace serde-yaml with serde-saphyr (again)

6b2b8bc

serde-saphyr has way better error message, and it is written in safe Rust.

j178 force-pushed the serde-saphyr branch from 069f401 to 6b2b8bc Compare February 1, 2026 13:07

j178 commented Feb 1, 2026

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crates/prek/src/config.rs Show resolved Hide resolved

j178 mentioned this pull request Feb 1, 2026

error: Failed to parse .pre-commit-config.yaml #1111

Closed

j178 marked this pull request as ready for review February 2, 2026 12:19

Copilot AI review requested due to automatic review settings February 2, 2026 12:19

Copilot started reviewing on behalf of j178 February 2, 2026 12:19 View session

j178 merged commit b070282 into master Feb 2, 2026
52 checks passed

j178 deleted the serde-saphyr branch February 2, 2026 12:19

Copilot AI reviewed Feb 2, 2026

View reviewed changes

BrewTestBot mentioned this pull request Feb 6, 2026

prek 0.3.2 Homebrew/homebrew-core#266179

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Replace serde-yaml with serde-saphyr (again)#1520

Replace serde-yaml with serde-saphyr (again)#1520
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	/// Serialize a YAML scalar while preserving the caller's quote style.
	pub(crate) fn serialize_yaml_scalar(value: &str, quote: &str) -> Result<String> {

		let config = serde_saphyr::from_str(&content)
		.map_err(\|e\| Error::Yaml(path.user_display().to_string(), Box::new(e)))?;

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