Add aliases for hook priorities

[chrisoro]

In projects with lots of hooks (and therefore repos) I found it very hard to follow which hooks run in which priority. I want to run as many as possible in parallel and therefore assign them to groups. Until now, I had to assign the same integer to hooks that can run at the same time (=belong to the same group), so I always wished for this feature.

I tried to do it in such a way that needs minimal changes and decided to basically only change the config parsing. In the end, it will still result in an u32 and all further logic still applies.

I also changed validate_group_name to validate_config_name to apply the same restrictions to the priorities names as for groups.

Used AI to find all docs that needs to be updated and updated them.

My first contribution here, so tell me if I missed something or if you want some changes.

[codecov]

Codecov Report

❌ Patch coverage is 94.59459% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 93.36%. Comparing base (79cf621) to head (f125fc7).

Files with missing lines	Patch %	Lines
crates/prek/src/config.rs	93.54%	4 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #2331   +/-   ##
=======================================
  Coverage   93.36%   93.36%           
=======================================
  Files         129      129           
  Lines       27408    27470   +62     
=======================================
+ Hits        25589    25647   +58     
- Misses       1819     1823    +4     

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[prek-ci-bot]

📦 Cargo Bloat Comparison

Binary size change: +0.00% (29.1 MiB → 29.1 MiB)

Expand for cargo-bloat output

Head Branch Results

 File  .text     Size             Crate Name
 1.1%   2.3% 332.0KiB        aws_lc_sys aws_lc_0_42_0_aes_gcm_encrypt_avx512
 1.1%   2.3% 332.0KiB        aws_lc_sys aws_lc_0_42_0_aes_gcm_decrypt_avx512
 0.3%   0.6%  79.3KiB              prek <prek::cli::Command as clap_builder::derive::Subcommand>::augment_subcommands
 0.2%   0.4%  58.0KiB              prek <<prek::config::Config as serde_core::de::Deserialize>::deserialize::__Visitor as serde_core::de::Visitor>::visit_map::<<serde_saphyr::de::deserializer::YamlDeserializer as serde_core::de::Deserializer>::deserialize_map::MA>
 0.2%   0.3%  49.4KiB annotate_snippets annotate_snippets::renderer::render::render
 0.1%   0.3%  42.8KiB              prek prek::cli::run::run::run::{closure#0}
 0.1%   0.3%  39.4KiB              prek prek::run::{closure#0}
 0.1%   0.2%  33.4KiB              prek prek::archive::unpack::<fs_err::tokio::file::File, &std::path::PathBuf>::{closure#0}
 0.1%   0.2%  32.1KiB              prek <prek::cli::RunOptions as clap_builder::derive::Args>::augment_args
 0.1%   0.2%  30.6KiB              prek prek::cli::update::update::{closure#0}
 0.1%   0.2%  30.1KiB     granit_parser <granit_parser::scanner::Scanner<granit_parser::input::str::StrInput>>::fetch_more_tokens
 0.1%   0.2%  29.3KiB              prek <<prek::config::RemoteHook as serde_core::de::Deserialize>::deserialize::__Visitor as serde_core::de::Visitor>::visit_map::<<serde_saphyr::de::deserializer::YamlDeserializer as serde_core::de::Deserializer>::deserialize_map::MA>
 0.1%   0.2%  28.6KiB    cargo_metadata <&mut serde_json::de::Deserializer<serde_json::read::StrRead> as serde_core::de::Deserializer>::deserialize_struct::<<cargo_metadata::Package as serde_core::de::Deserialize>::deserialize::__Visitor>
 0.1%   0.2%  28.0KiB        aws_lc_sys aws_lc_0_42_0_edwards25519_scalarmuldouble_alt
 0.1%   0.2%  27.5KiB        aws_lc_sys aws_lc_0_42_0_edwards25519_scalarmuldouble
 0.1%   0.2%  25.9KiB              prek prek::cli::try_repo::try_repo::{closure#0}
 0.1%   0.2%  25.6KiB              prek <<prek::config::LocalHook as serde_core::de::Deserialize>::deserialize::__Visitor as serde_core::de::Visitor>::visit_map::<<serde_saphyr::de::deserializer::YamlDeserializer as serde_core::de::Deserializer>::deserialize_map::MA>
 0.1%   0.2%  25.2KiB              prek <<prek::config::UpdateOptions as serde_core::de::Deserialize>::deserialize::__Visitor as serde_core::de::Visitor>::visit_map::<<serde_saphyr::de::deserializer::YamlDeserializer as serde_core::de::Deserializer>::deserialize_map::MA>
 0.1%   0.2%  24.9KiB               xml <xml::reader::parser::PullParser>::dispatch_token
 0.1%   0.2%  24.4KiB              prek <prek::languages::node::installer::NodeInstaller>::install::{closure#0}
42.1%  88.0%  12.3MiB                   And 25801 smaller methods. Use -n N to show more.
47.8% 100.0%  13.9MiB                   .text section size, the file size is 29.1MiB

Base Branch Results

 File  .text     Size             Crate Name
 1.1%   2.3% 332.0KiB        aws_lc_sys aws_lc_0_42_0_aes_gcm_encrypt_avx512
 1.1%   2.3% 332.0KiB        aws_lc_sys aws_lc_0_42_0_aes_gcm_decrypt_avx512
 0.3%   0.6%  79.3KiB              prek <prek::cli::Command as clap_builder::derive::Subcommand>::augment_subcommands
 0.2%   0.4%  52.4KiB              prek <<prek::config::Config as serde_core::de::Deserialize>::deserialize::__Visitor as serde_core::de::Visitor>::visit_map::<<serde_saphyr::de::deserializer::YamlDeserializer as serde_core::de::Deserializer>::deserialize_map::MA>
 0.2%   0.3%  49.4KiB annotate_snippets annotate_snippets::renderer::render::render
 0.1%   0.3%  41.3KiB              prek prek::cli::run::run::run::{closure#0}
 0.1%   0.3%  39.5KiB              prek prek::run::{closure#0}
 0.1%   0.2%  33.2KiB              prek prek::archive::unpack::<fs_err::tokio::file::File, &std::path::PathBuf>::{closure#0}
 0.1%   0.2%  32.1KiB              prek <prek::cli::RunOptions as clap_builder::derive::Args>::augment_args
 0.1%   0.2%  30.1KiB     granit_parser <granit_parser::scanner::Scanner<granit_parser::input::str::StrInput>>::fetch_more_tokens
 0.1%   0.2%  28.6KiB    cargo_metadata <&mut serde_json::de::Deserializer<serde_json::read::StrRead> as serde_core::de::Deserializer>::deserialize_struct::<<cargo_metadata::Package as serde_core::de::Deserialize>::deserialize::__Visitor>
 0.1%   0.2%  28.3KiB              prek <<prek::config::RemoteHook as serde_core::de::Deserialize>::deserialize::__Visitor as serde_core::de::Visitor>::visit_map::<<serde_saphyr::de::deserializer::YamlDeserializer as serde_core::de::Deserializer>::deserialize_map::MA>
 0.1%   0.2%  28.0KiB        aws_lc_sys aws_lc_0_42_0_edwards25519_scalarmuldouble_alt
 0.1%   0.2%  27.5KiB        aws_lc_sys aws_lc_0_42_0_edwards25519_scalarmuldouble
 0.1%   0.2%  26.2KiB              prek prek::cli::try_repo::try_repo::{closure#0}
 0.1%   0.2%  25.6KiB              prek <<prek::config::LocalHook as serde_core::de::Deserialize>::deserialize::__Visitor as serde_core::de::Visitor>::visit_map::<<serde_saphyr::de::deserializer::YamlDeserializer as serde_core::de::Deserializer>::deserialize_map::MA>
 0.1%   0.2%  25.2KiB              prek <<prek::config::UpdateOptions as serde_core::de::Deserialize>::deserialize::__Visitor as serde_core::de::Visitor>::visit_map::<<serde_saphyr::de::deserializer::YamlDeserializer as serde_core::de::Deserializer>::deserialize_map::MA>
 0.1%   0.2%  24.9KiB               xml <xml::reader::parser::PullParser>::dispatch_token
 0.1%   0.2%  24.4KiB              prek <prek::languages::node::installer::NodeInstaller>::install::{closure#0}
 0.1%   0.2%  24.0KiB     granit_parser <granit_parser::scanner::Scanner<serde_saphyr::de::buffered_input::ReaderInput>>::fetch_more_tokens
42.0%  88.1%  12.2MiB                   And 25792 smaller methods. Use -n N to show more.
47.7% 100.0%  13.9MiB                   .text section size, the file size is 29.1MiB

[prek-ci-bot]

⚡️ Hyperfine Benchmarks

Summary: 0 regressions, 0 improvements above the 10% threshold.

Environment

• OS: Linux 6.17.0-1020-azure
• CPU: 4 cores
• prek version: prek 0.4.10+4 (f949f9f 2026-07-18)
• Rust version: rustc 1.97.1 (8bab26f4f 2026-07-14)
• Hyperfine version: hyperfine 1.20.0

CLI Commands

Benchmarking basic commands in the main repo:

prek --version

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base --version	2.2 ± 0.1	2.1	2.5	1.00
prek-head --version	2.3 ± 0.1	2.1	2.8	1.05 ± 0.07

prek list

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base list	10.0 ± 0.2	9.5	10.5	1.00
prek-head list	10.2 ± 0.2	9.7	11.0	1.02 ± 0.03

prek validate-config .pre-commit-config.yaml

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base validate-config .pre-commit-config.yaml	3.3 ± 0.1	3.1	3.5	1.00
prek-head validate-config .pre-commit-config.yaml	3.4 ± 0.9	3.1	9.6	1.02 ± 0.27

prek sample-config

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base sample-config	2.6 ± 0.1	2.4	3.0	1.02 ± 0.05
prek-head sample-config	2.5 ± 0.1	2.3	2.7	1.00

Cold vs Warm Runs

Comparing first run (cold) vs subsequent runs (warm cache):

prek run --all-files (cold - no cache)

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run --all-files	80.9 ± 4.0	75.5	88.0	1.03 ± 0.06
prek-head run --all-files	78.4 ± 2.1	76.3	81.8	1.00

prek run --all-files (warm - with cache)

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run --all-files	79.6 ± 2.2	75.4	84.3	1.00 ± 0.04
prek-head run --all-files	79.3 ± 2.2	74.9	83.2	1.00

Full Hook Suite

Running the builtin hook suite on the benchmark workspace:

prek run --all-files (full builtin hook suite)

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run --all-files	80.0 ± 2.5	75.8	85.3	1.00
prek-head run --all-files	80.1 ± 3.4	73.7	90.7	1.00 ± 0.05

Individual Hook Performance

Benchmarking each hook individually on the test repo:

prek run trailing-whitespace --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run trailing-whitespace --all-files	21.2 ± 0.3	20.4	22.1	1.01 ± 0.02
prek-head run trailing-whitespace --all-files	20.9 ± 0.4	20.3	21.8	1.00

prek run end-of-file-fixer --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run end-of-file-fixer --all-files	27.8 ± 2.2	25.2	33.2	1.00
prek-head run end-of-file-fixer --all-files	28.0 ± 2.1	25.3	32.9	1.01 ± 0.11

prek run check-json --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-json --all-files	8.5 ± 0.3	8.1	9.2	1.02 ± 0.05
prek-head run check-json --all-files	8.4 ± 0.3	7.6	9.0	1.00

prek run check-yaml --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-yaml --all-files	8.4 ± 0.2	8.0	8.8	1.00
prek-head run check-yaml --all-files	8.4 ± 0.7	8.0	11.9	1.00 ± 0.09

prek run check-toml --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-toml --all-files	8.2 ± 0.3	7.5	8.7	1.00 ± 0.06
prek-head run check-toml --all-files	8.2 ± 0.3	7.7	9.4	1.00

prek run check-xml --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-xml --all-files	8.0 ± 0.3	7.5	8.7	1.00
prek-head run check-xml --all-files	8.0 ± 0.3	7.7	9.1	1.00 ± 0.05

prek run detect-private-key --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run detect-private-key --all-files	14.5 ± 1.3	12.7	16.8	1.00
prek-head run detect-private-key --all-files	14.7 ± 1.3	12.8	17.1	1.01 ± 0.13

prek run fix-byte-order-marker --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run fix-byte-order-marker --all-files	19.4 ± 0.8	17.8	21.1	1.03 ± 0.06
prek-head run fix-byte-order-marker --all-files	18.8 ± 0.7	17.7	20.8	1.00

Installation Performance

Benchmarking hook installation (fast path hooks skip Python setup):

prek install-hooks (cold - no cache)

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base install-hooks	4.7 ± 0.1	4.7	4.8	1.00
prek-head install-hooks	4.7 ± 0.1	4.7	4.9	1.00 ± 0.02

prek install-hooks (warm - with cache)

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base install-hooks	4.8 ± 0.1	4.7	4.9	1.00
prek-head install-hooks	4.8 ± 0.1	4.7	5.0	1.02 ± 0.03

File Filtering/Scoping Performance

Testing different file selection modes:

prek run (staged files only)

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run	38.9 ± 1.6	37.4	44.5	1.00
prek-head run	39.6 ± 2.7	36.4	49.0	1.02 ± 0.08

prek run --files '*.json' (specific file type)

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run --files '*.json'	8.5 ± 0.2	8.2	9.0	1.00 ± 0.03
prek-head run --files '*.json'	8.4 ± 0.2	8.1	8.7	1.00

Workspace Discovery & Initialization

Benchmarking hook discovery and initialization overhead:

prek run --dry-run --all-files (measures init overhead)

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run --dry-run --all-files	7.4 ± 0.2	7.2	7.7	1.01 ± 0.03
prek-head run --dry-run --all-files	7.3 ± 0.2	6.9	7.8	1.00

Meta Hooks Performance

Benchmarking meta hooks separately:

prek run check-hooks-apply --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-hooks-apply --all-files	12.6 ± 0.2	12.1	13.0	1.00
prek-head run check-hooks-apply --all-files	12.8 ± 0.3	12.4	13.3	1.02 ± 0.03

prek run check-useless-excludes --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-useless-excludes --all-files	11.3 ± 0.4	11.0	12.6	1.03 ± 0.04
prek-head run check-useless-excludes --all-files	11.1 ± 0.2	10.8	11.4	1.00

prek run identity --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run identity --all-files	10.4 ± 0.1	10.1	10.7	1.00
prek-head run identity --all-files	10.4 ± 0.1	10.2	10.8	1.01 ± 0.02

[j178]

Thanks! I’m concerned that named priorities would introduce a second grouping concept alongside groups, but with unrelated semantics: groups select hooks, while priorities schedule them. The same natural names, such as format, checks, or tests, are likely to be used for both, which could be confusing.

YAML anchors can be a workaround before we add named priorities:

- id: ruff
  priority: &checks 10

- id: mypy
  priority: *checks

[chrisoro]

I agree but we fully embraced prek dropping pre-commit compatibility and switched to prek.toml. There are no anchors in toml.

I see your point but selection and order are ultimately two different things. Do you think this is just a naming problem? We could also enforce the priorities to all start/end with a specific prefix/suffix to make it clearer.

Imo this would be a great feature since assigning and maintaining int based priorities in a toml file with 50 hooks is a real pain

[j178]

Thanks!