Remove PREK_MAX_CONCURRENCY

[j178]

Removes the deprecated PREK_MAX_CONCURRENCY fallback.

[Copilot]

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.96%. Comparing base (fd44aab) to head (eedda1b).

Additional details and impacted files

@@                   Coverage Diff                   @@
##           drop-update-aliases    #2620      +/-   ##
=======================================================
- Coverage                93.97%   93.96%   -0.02%     
=======================================================
  Files                      140      140              
  Lines                    29679    29578     -101     
=======================================================
- Hits                     27890    27792      -98     
+ Misses                    1789     1786       -3     

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[prek-ci-bot]

📦 Cargo Bloat Comparison

.text size change: +0.00% (12.5 MiB → 12.5 MiB)

Expand for cargo-bloat output

Head Branch Results

File  .text     Size             Crate Name
0.1%   2.6% 332.0KiB        aws_lc_sys aws_lc_0_44_0_aes_gcm_encrypt_avx512
0.1%   2.6% 332.0KiB        aws_lc_sys aws_lc_0_44_0_aes_gcm_decrypt_avx512
0.0%   0.9% 113.8KiB              prek <prek::cli::Command as clap_builder::derive::Subcommand>::augment_subcommands
0.0%   0.4%  51.4KiB              prek <<prek::config::hook::HookWire 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>
0.0%   0.4%  48.7KiB annotate_snippets annotate_snippets::renderer::render::render
0.0%   0.3%  44.6KiB              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>
0.0%   0.3%  36.8KiB              prek prek::run::{closure#0}
0.0%   0.3%  36.7KiB              prek <prek::cli::RunOptions as clap_builder::derive::Args>::augment_args
0.0%   0.3%  35.3KiB              prek <prek::languages::rust::rust::Rust as prek::languages::LanguageBackend>::install::{closure#0}
0.0%   0.3%  33.4KiB              prek prek::cli::run::run::run::{closure#0}
0.0%   0.2%  28.6KiB      serde_saphyr <granit_parser::scanner::Scanner<granit_parser::input::str::StrInput>>::fetch_more_tokens
0.0%   0.2%  28.6KiB              prek prek::archive::unpack::<fs_err::tokio::file::File, &std::path::PathBuf>::{closure#0}
0.0%   0.2%  28.0KiB        aws_lc_sys aws_lc_0_44_0_edwards25519_scalarmuldouble_alt
0.0%   0.2%  27.8KiB      serde_saphyr <granit_parser::scanner::Scanner<granit_parser::input::str::StrInput>>::fetch_more_tokens
0.0%   0.2%  27.5KiB        aws_lc_sys aws_lc_0_44_0_edwards25519_scalarmuldouble
0.0%   0.2%  27.4KiB              toml <toml::de::deserializer::value::ValueDeserializer as serde_core::de::Deserializer>::deserialize_any::<<prek::config::hook::HookWire as serde_core::de::Deserialize>::deserialize::__Visitor>
0.0%   0.2%  27.0KiB              prek prek::archive::unpack::<fs_err::tokio::file::File, &std::path::PathBuf>::{closure#0}
0.0%   0.2%  27.0KiB              prek prek::archive::unpack::<fs_err::tokio::file::File, &std::path::PathBuf>::{closure#0}
0.0%   0.2%  26.9KiB              prek prek::archive::unpack::<fs_err::tokio::file::File, &std::path::PathBuf>::{closure#0}
0.0%   0.2%  26.9KiB              prek prek::archive::unpack::<fs_err::tokio::file::File, &std::path::PathBuf>::{closure#0}
4.2%  86.7%  10.8MiB                   And 20265 smaller methods. Use -n N to show more.
4.9% 100.0%  12.5MiB                   .text section size, the file size is 256.8MiB

Base Branch Results

File  .text     Size             Crate Name
0.1%   2.6% 332.0KiB        aws_lc_sys aws_lc_0_44_0_aes_gcm_encrypt_avx512
0.1%   2.6% 332.0KiB        aws_lc_sys aws_lc_0_44_0_aes_gcm_decrypt_avx512
0.0%   0.9% 113.7KiB              prek <prek::cli::Command as clap_builder::derive::Subcommand>::augment_subcommands
0.0%   0.4%  51.4KiB              prek <<prek::config::hook::HookWire 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>
0.0%   0.4%  48.7KiB annotate_snippets annotate_snippets::renderer::render::render
0.0%   0.3%  44.6KiB              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>
0.0%   0.3%  44.5KiB              prek prek::run::{closure#0}
0.0%   0.3%  37.1KiB              prek <prek::cli::RunOptions as clap_builder::derive::Args>::augment_args
0.0%   0.3%  35.3KiB              prek <prek::languages::rust::rust::Rust as prek::languages::LanguageBackend>::install::{closure#0}
0.0%   0.3%  33.6KiB              prek prek::cli::run::run::run::{closure#0}
0.0%   0.2%  29.1KiB              prek prek::archive::unpack::<fs_err::tokio::file::File, &std::path::PathBuf>::{closure#0}
0.0%   0.2%  28.6KiB      serde_saphyr <granit_parser::scanner::Scanner<granit_parser::input::str::StrInput>>::fetch_more_tokens
0.0%   0.2%  28.0KiB        aws_lc_sys aws_lc_0_44_0_edwards25519_scalarmuldouble_alt
0.0%   0.2%  27.8KiB      serde_saphyr <granit_parser::scanner::Scanner<granit_parser::input::str::StrInput>>::fetch_more_tokens
0.0%   0.2%  27.5KiB        aws_lc_sys aws_lc_0_44_0_edwards25519_scalarmuldouble
0.0%   0.2%  27.4KiB              toml <toml::de::deserializer::value::ValueDeserializer as serde_core::de::Deserializer>::deserialize_any::<<prek::config::hook::HookWire as serde_core::de::Deserialize>::deserialize::__Visitor>
0.0%   0.2%  27.0KiB              prek prek::archive::unpack::<fs_err::tokio::file::File, &std::path::PathBuf>::{closure#0}
0.0%   0.2%  27.0KiB              prek prek::archive::unpack::<fs_err::tokio::file::File, &std::path::PathBuf>::{closure#0}
0.0%   0.2%  27.0KiB              prek prek::archive::unpack::<fs_err::tokio::file::File, &std::path::PathBuf>::{closure#0}
0.0%   0.2%  26.9KiB              prek prek::archive::unpack::<fs_err::tokio::file::File, &std::path::PathBuf>::{closure#0}
4.2%  86.6%  10.9MiB                   And 20250 smaller methods. Use -n N to show more.
4.9% 100.0%  12.5MiB                   .text section size, the file size is 257.1MiB

[prek-ci-bot]

⚡️ Hyperfine Benchmarks

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

Environment

• OS: Linux 6.17.0-1022-azure
• CPU: 4 cores
• prek version: prek 0.4.14+31 (29c4adc 2026-08-26)
• Rust version: rustc 1.98.0 (88d9e12ae 2026-08-18)
• 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	2.4 ± 0.1	2.3	2.8	1.05 ± 0.05
prek-head --version	2.3 ± 0.1	2.2	2.5	1.00

prek list

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base list	9.6 ± 0.3	9.2	12.1	1.00
prek-head list	9.9 ± 4.0	9.1	47.5	1.04 ± 0.42

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

⏭️ Skipped: .pre-commit-config.yaml not found

prek sample-config

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base sample-config	2.7 ± 0.2	2.6	3.8	1.03 ± 0.06
prek-head sample-config	2.6 ± 0.0	2.6	2.8	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	38.1 ± 1.4	36.0	40.7	1.00
prek-head run --all-files	38.5 ± 1.5	35.8	40.4	1.01 ± 0.06

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

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run --all-files	38.1 ± 1.2	35.3	40.2	1.01 ± 0.05
prek-head run --all-files	37.7 ± 1.4	35.6	41.0	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	37.7 ± 1.1	34.9	40.8	1.00 ± 0.04
prek-head run --all-files	37.6 ± 1.2	35.2	41.2	1.00

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	13.0 ± 0.6	12.1	15.1	1.00 ± 0.06
prek-head run trailing-whitespace --all-files	13.0 ± 0.5	12.3	15.1	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	11.3 ± 0.5	10.5	12.5	1.00
prek-head run end-of-file-fixer --all-files	11.6 ± 0.7	10.7	14.0	1.02 ± 0.07

prek run check-json --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-json --all-files	8.2 ± 0.2	7.8	8.8	1.01 ± 0.04
prek-head run check-json --all-files	8.2 ± 0.3	7.6	8.7	1.00

prek run check-yaml --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-yaml --all-files	7.8 ± 0.2	7.5	8.2	1.00
prek-head run check-yaml --all-files	7.9 ± 0.4	7.5	9.1	1.01 ± 0.05

prek run check-toml --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-toml --all-files	8.4 ± 0.3	7.9	9.2	1.04 ± 0.05
prek-head run check-toml --all-files	8.0 ± 0.2	7.6	8.5	1.00

prek run check-xml --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-xml --all-files	7.9 ± 0.2	7.5	8.4	1.00
prek-head run check-xml --all-files	7.9 ± 0.3	7.5	8.9	1.01 ± 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	11.6 ± 0.6	10.6	12.8	1.04 ± 0.07
prek-head run detect-private-key --all-files	11.2 ± 0.5	10.5	12.0	1.00

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	12.6 ± 0.8	11.7	14.9	1.00
prek-head run fix-byte-order-marker --all-files	12.7 ± 0.9	11.4	14.4	1.01 ± 0.10

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 ± 0.0	4.7	4.8	1.01 ± 0.01
prek-head install-hooks	4.7 ± 0.1	4.6	4.7	1.00

prek install-hooks (warm - with cache)

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base install-hooks	4.7 ± 0.1	4.7	4.8	1.01 ± 0.02
prek-head install-hooks	4.6 ± 0.1	4.6	4.7	1.00

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	25.2 ± 0.2	24.8	25.6	1.00
prek-head run	25.2 ± 0.4	24.6	26.1	1.00 ± 0.02

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

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run --files '*.json'	5.5 ± 0.1	5.3	5.6	1.02 ± 0.02
prek-head run --files '*.json'	5.4 ± 0.1	5.2	5.6	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	7.3 ± 0.1	7.1	7.5	1.01 ± 0.02
prek-head run --dry-run --all-files	7.2 ± 0.1	7.0	7.3	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	8.7 ± 0.1	8.6	8.8	1.01 ± 0.01
prek-head run check-hooks-apply --all-files	8.6 ± 0.1	8.4	8.7	1.00

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

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-useless-excludes --all-files	8.6 ± 0.1	8.5	8.7	1.01 ± 0.01
prek-head run check-useless-excludes --all-files	8.5 ± 0.1	8.3	8.6	1.00

prek run identity --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run identity --all-files	7.7 ± 0.2	7.5	8.1	1.02 ± 0.02
prek-head run identity --all-files	7.5 ± 0.1	7.3	7.7	1.00