Add destroyed-symlinks builtin hook

[j178]

Closes #1848

[codecov]

Codecov Report

❌ Patch coverage is 94.54545% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 91.93%. Comparing base (fc529df) to head (ad7b40f).
⚠️ Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
...k/src/hooks/pre_commit_hooks/destroyed_symlinks.rs	94.63%	8 Missing ⚠️
crates/prek/src/hooks/pre_commit_hooks/mod.rs	0.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1851      +/-   ##
==========================================
+ Coverage   91.91%   91.93%   +0.02%     
==========================================
  Files         106      107       +1     
  Lines       20994    21159     +165     
==========================================
+ Hits        19296    19453     +157     
- Misses       1698     1706       +8     

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[Copilot]

Pull request overview

Adds the upstream pre-commit-hooks destroyed-symlinks hook as a repo: builtin hook in prek, including implementation, registration, docs, schema, and test coverage.

Changes:

• Implement destroyed-symlinks hook logic (via git status --porcelain=v2 + blob comparisons) and wire it into builtin hook dispatch.
• Document the new builtin hook and add it to the JSON schema enum.
• Update integration/snapshot tests for builtin listing and hook behavior.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
crates/prek/src/hooks/pre_commit_hooks/destroyed_symlinks.rs	New hook implementation: parses porcelain v2 output and detects destroyed symlinks by comparing HEAD symlink blob vs staged file blob.
crates/prek/src/hooks/pre_commit_hooks/mod.rs	Registers DestroyedSymlinks in the pre-commit-hooks fast-path enum and dispatch.
crates/prek/src/hooks/builtin_hooks/mod.rs	Adds destroyed-symlinks to builtin hook enum, dispatch, and builtin hook metadata (id/name/description/etc.).
crates/prek/tests/builtin_hooks.rs	Adds an integration test exercising the hook behavior (including newline tolerance).
crates/prek/tests/list_builtins.rs	Updates snapshots for util list-builtins (basic/verbose/json) to include the new hook.
docs/builtin.md	Adds documentation entry and per-hook section for destroyed-symlinks.
prek.schema.json	Adds destroyed-symlinks to the BuiltinHooks enum in the generated schema.

[chatgpt-codex-connector]

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[prek-ci-bot]

📦 Cargo Bloat Comparison

Binary size change: -0.40% (25.1 MiB → 25.0 MiB)

Expand for cargo-bloat output

Head Branch Results

 File  .text     Size             Crate Name
 1.3%   2.7% 332.0KiB        aws_lc_sys aws_lc_0_39_0_aes_gcm_encrypt_avx512
 1.3%   2.7% 332.0KiB        aws_lc_sys aws_lc_0_39_0_aes_gcm_decrypt_avx512
 0.3%   0.7%  81.3KiB              prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.3%   0.6%  74.8KiB              prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.3%   0.6%  69.1KiB             prek? <prek::cli::Command as clap_builder::derive::Subcommand>::augment_subcommands
 0.2%   0.5%  56.9KiB              prek prek::languages::<impl prek::config::Language>::install::{{closure}}
 0.2%   0.4%  51.0KiB annotate_snippets annotate_snippets::renderer::render::render
 0.2%   0.4%  47.1KiB              prek prek::run::{{closure}}
 0.2%   0.3%  41.8KiB              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%  28.0KiB        aws_lc_sys aws_lc_0_39_0_edwards25519_scalarmuldouble_alt
 0.1%   0.2%  27.8KiB      serde_saphyr saphyr_parser_bw::scanner::Scanner<T>::fetch_more_tokens
 0.1%   0.2%  27.5KiB        aws_lc_sys aws_lc_0_39_0_edwards25519_scalarmuldouble
 0.1%   0.2%  26.2KiB              prek prek::cli::try_repo::try_repo::{{closure}}
 0.1%   0.2%  25.4KiB             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%  24.4KiB               std core::ptr::drop_in_place<prek::languages::<impl prek::config::Language>::install::{{closure}}>
 0.1%   0.2%  23.1KiB              prek prek::hooks::meta_hooks::MetaHooks::run::{{closure}}
 0.1%   0.2%  22.4KiB      serde_saphyr saphyr_parser_bw::scanner::Scanner<T>::fetch_more_tokens
 0.1%   0.2%  22.3KiB         [Unknown] Lp384_montjscalarmul_alt_p384_montjadd
 0.1%   0.2%  21.8KiB              prek prek::main
41.4%  86.0%  10.3MiB                   And 23388 smaller methods. Use -n N to show more.
48.1% 100.0%  12.0MiB                   .text section size, the file size is 25.0MiB

Base Branch Results

 File  .text     Size             Crate Name
 1.3%   2.7% 332.0KiB        aws_lc_sys aws_lc_0_39_0_aes_gcm_encrypt_avx512
 1.3%   2.7% 332.0KiB        aws_lc_sys aws_lc_0_39_0_aes_gcm_decrypt_avx512
 0.3%   0.6%  80.0KiB              prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.3%   0.6%  72.2KiB              prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.3%   0.6%  69.3KiB             prek? <prek::cli::Command as clap_builder::derive::Subcommand>::augment_subcommands
 0.2%   0.5%  56.8KiB              prek prek::languages::<impl prek::config::Language>::install::{{closure}}
 0.2%   0.4%  51.0KiB annotate_snippets annotate_snippets::renderer::render::render
 0.2%   0.4%  46.0KiB              prek prek::run::{{closure}}
 0.2%   0.3%  41.8KiB              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%  28.0KiB        aws_lc_sys aws_lc_0_39_0_edwards25519_scalarmuldouble_alt
 0.1%   0.2%  27.8KiB      serde_saphyr saphyr_parser_bw::scanner::Scanner<T>::fetch_more_tokens
 0.1%   0.2%  27.5KiB        aws_lc_sys aws_lc_0_39_0_edwards25519_scalarmuldouble
 0.1%   0.2%  26.6KiB             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%  25.9KiB              prek prek::cli::try_repo::try_repo::{{closure}}
 0.1%   0.2%  24.2KiB               std core::ptr::drop_in_place<prek::languages::<impl prek::config::Language>::install::{{closure}}>
 0.1%   0.2%  23.0KiB              prek prek::hooks::meta_hooks::MetaHooks::run::{{closure}}
 0.1%   0.2%  22.4KiB      serde_saphyr saphyr_parser_bw::scanner::Scanner<T>::fetch_more_tokens
 0.1%   0.2%  22.3KiB         [Unknown] Lp384_montjscalarmul_alt_p384_montjadd
 0.1%   0.2%  21.7KiB              prek prek::workspace::Project::init_hooks::{{closure}}
41.3%  86.1%  10.4MiB                   And 23709 smaller methods. Use -n N to show more.
48.0% 100.0%  12.1MiB                   .text section size, the file size is 25.1MiB

[prek-ci-bot]

⚡️ Hyperfine Benchmarks

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

Environment

• OS: Linux 6.14.0-1017-azure
• CPU: 4 cores
• prek version: prek 0.3.6+31 (b9ad36b 2026-03-22)
• Rust version: rustc 1.94.0 (4a4ef493e 2026-03-02)
• 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	2.2	2.6	1.03 ± 0.05
prek-head --version	2.3 ± 0.1	2.2	2.7	1.00

prek list

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base list	8.8 ± 0.1	8.7	10.0	1.01 ± 0.02
prek-head list	8.8 ± 0.1	8.6	9.0	1.00

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

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base validate-config .pre-commit-config.yaml	3.2 ± 0.3	3.1	5.6	1.02 ± 0.11
prek-head validate-config .pre-commit-config.yaml	3.1 ± 0.0	3.1	3.2	1.00

prek sample-config

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base sample-config	2.6 ± 0.0	2.5	2.7	1.00
prek-head sample-config	2.6 ± 0.0	2.6	2.7	1.01 ± 0.02

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	153.6 ± 1.6	151.7	156.8	1.00
prek-head run --all-files	154.1 ± 1.5	152.2	157.1	1.00 ± 0.01

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

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run --all-files	154.5 ± 2.2	151.2	158.3	1.01 ± 0.02
prek-head run --all-files	153.5 ± 2.6	148.6	160.7	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	153.0 ± 2.3	149.3	159.5	1.00
prek-head run --all-files	158.1 ± 26.5	148.5	336.1	1.03 ± 0.17

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	21.5 ± 0.4	20.4	22.0	1.02 ± 0.03
prek-head run trailing-whitespace --all-files	21.1 ± 0.4	20.3	21.9	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	27.4 ± 1.9	25.0	31.2	1.01 ± 0.09
prek-head run end-of-file-fixer --all-files	27.1 ± 1.5	24.9	30.9	1.00

prek run check-json --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-json --all-files	12.8 ± 0.3	12.3	13.5	1.05 ± 0.04
prek-head run check-json --all-files	12.2 ± 0.3	11.6	13.0	1.00

prek run check-yaml --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-yaml --all-files	11.7 ± 0.2	11.5	12.3	1.00
prek-head run check-yaml --all-files	11.8 ± 0.2	11.5	12.2	1.00 ± 0.02

prek run check-toml --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-toml --all-files	12.0 ± 0.2	11.5	12.5	1.00 ± 0.03
prek-head run check-toml --all-files	12.0 ± 0.3	11.4	12.6	1.00

prek run check-xml --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-xml --all-files	12.0 ± 0.2	11.5	12.6	1.00
prek-head run check-xml --all-files	12.2 ± 0.5	11.5	13.9	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	17.9 ± 1.1	16.3	20.8	1.00 ± 0.09
prek-head run detect-private-key --all-files	17.8 ± 1.0	16.0	20.2	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	23.4 ± 1.5	20.6	25.9	1.01 ± 0.09
prek-head run fix-byte-order-marker --all-files	23.1 ± 1.5	20.4	25.8	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	4.8 ± 0.1	4.7	4.9	1.01 ± 0.02
prek-head install-hooks	4.7 ± 0.1	4.7	4.8	1.00

prek install-hooks (warm - with cache)

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base install-hooks	4.8 ± 0.0	4.7	4.8	1.00
prek-head install-hooks	4.8 ± 0.1	4.7	4.8	1.00 ± 0.01

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	52.5 ± 1.0	51.2	54.9	1.00 ± 0.03
prek-head run	52.4 ± 1.0	51.0	54.3	1.00

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

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run --files '*.json'	8.9 ± 0.1	8.8	9.2	1.00
prek-head run --files '*.json'	9.0 ± 0.1	8.9	9.3	1.01 ± 0.02

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	13.9 ± 0.2	13.6	14.4	1.00
prek-head run --dry-run --all-files	13.9 ± 0.2	13.6	14.6	1.00 ± 0.02

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	13.9 ± 0.1	13.8	14.1	1.00
prek-head run check-hooks-apply --all-files	14.0 ± 0.1	13.9	14.2	1.01 ± 0.01

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

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-useless-excludes --all-files	12.4 ± 0.1	12.3	12.5	1.00 ± 0.01
prek-head run check-useless-excludes --all-files	12.4 ± 0.1	12.2	12.6	1.00

prek run identity --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run identity --all-files	10.8 ± 0.1	10.7	11.0	1.00
prek-head run identity --all-files	10.9 ± 0.1	10.7	11.2	1.00 ± 0.01

[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

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[Copilot]

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 3 comments.

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💡 Codex Review

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