Identify 'mts' and 'cts' as TypeScript files

[j178]

Closes #2057

[Copilot]

Pull request overview

This PR updates prek-identify’s filename extension mapping so .cts and .mts are correctly classified as TypeScript (ts), matching how .ts is tagged and addressing #2057.

Changes:

• Add cts/mts → ["text", "ts"] mappings to the generated extension table.
• Add unit tests to validate tags_from_filename() returns ["text", "ts"] for .cts and .mts.
• Update the tag-generation script to persist these mappings via an explicit override.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
crates/prek-identify/src/tags.rs	Adds .cts and .mts extension entries mapping to the existing text + ts tagset.
crates/prek-identify/src/lib.rs	Extends tags_from_filename tests to cover .cts and .mts.
crates/prek-identify/gen.py	Introduces EXTENSION_OVERRIDES so the generated tags.rs consistently includes .cts/.mts TypeScript mappings.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.56%. Comparing base (6166275) to head (d559c8a).
⚠️ Report is 2 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #2209      +/-   ##
==========================================
- Coverage   92.59%   92.56%   -0.03%     
==========================================
  Files         125      125              
  Lines       26587    26591       +4     
==========================================
- Hits        24617    24613       -4     
- Misses       1970     1978       +8     

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[chatgpt-codex-connector]

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[chatgpt-codex-connector]

Avoid marking binary .mts media as TypeScript text

When a repository contains .mts media files (MPEG transport stream/AVCHD uses this extension), this unconditional mapping gives them both text and ts; tags_from_path only runs the binary sniffing path when no text/binary tag is already present, so those binary assets will no longer be tagged binary and can be passed to hooks using types: [text] or types: [ts]. Consider making the .mts TypeScript tag conditional on the file actually being text, so existing binary .mts assets are not misclassified.

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[prek-ci-bot]

📦 Cargo Bloat Comparison

Binary size change: +0.00% (26.6 MiB → 26.6 MiB)

Expand for cargo-bloat output

Head Branch Results

 File  .text     Size             Crate Name
 1.2%   2.5% 332.0KiB        aws_lc_sys aws_lc_0_41_0_aes_gcm_encrypt_avx512
 1.2%   2.5% 332.0KiB        aws_lc_sys aws_lc_0_41_0_aes_gcm_decrypt_avx512
 0.4%   0.7%  95.4KiB              prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.3%   0.7%  90.7KiB              prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.3%   0.6%  85.1KiB              prek prek::languages::<impl prek::config::Language>::install::{{closure}}
 0.3%   0.6%  79.4KiB             prek? <prek::cli::Command as clap_builder::derive::Subcommand>::augment_subcommands
 0.2%   0.4%  49.7KiB              prek prek::run::{{closure}}
 0.2%   0.4%  49.4KiB annotate_snippets annotate_snippets::renderer::render::render
 0.2%   0.3%  44.6KiB              prek prek::cli::run::run::run::{{closure}}
 0.2%   0.3%  43.9KiB             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%  32.0KiB               std core::ptr::drop_in_place<prek::languages::<impl prek::config::Language>::install::{{closure}}>
 0.1%   0.2%  31.8KiB             prek? <prek::cli::RunOptions as clap_builder::derive::Args>::augment_args
 0.1%   0.2%  29.4KiB     granit_parser granit_parser::scanner::Scanner<T>::fetch_more_tokens
 0.1%   0.2%  28.3KiB             prek? <prek::config::_::<impl serde_core::de::Deserialize for prek::config::RemoteHook>::deserialize::__Visitor as serde_core::de::Visitor>::visit_map
 0.1%   0.2%  28.0KiB        aws_lc_sys aws_lc_0_41_0_edwards25519_scalarmuldouble_alt
 0.1%   0.2%  27.5KiB        aws_lc_sys aws_lc_0_41_0_edwards25519_scalarmuldouble
 0.1%   0.2%  26.2KiB              prek prek::cli::try_repo::try_repo::{{closure}}
 0.1%   0.2%  24.8KiB             prek? <prek::config::_::<impl serde_core::de::Deserialize for prek::config::LocalHook>::deserialize::__Visitor as serde_core::de::Visitor>::visit_map
 0.1%   0.2%  22.9KiB     granit_parser granit_parser::scanner::Scanner<T>::fetch_more_tokens
 0.1%   0.2%  22.3KiB         [Unknown] Lp384_montjscalarmul_alt_p384_montjadd
41.8%  86.0%  11.1MiB                   And 24265 smaller methods. Use -n N to show more.
48.6% 100.0%  12.9MiB                   .text section size, the file size is 26.6MiB

Base Branch Results

 File  .text     Size             Crate Name
 1.2%   2.5% 332.0KiB        aws_lc_sys aws_lc_0_41_0_aes_gcm_encrypt_avx512
 1.2%   2.5% 332.0KiB        aws_lc_sys aws_lc_0_41_0_aes_gcm_decrypt_avx512
 0.4%   0.7%  95.4KiB              prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.3%   0.7%  90.7KiB              prek prek::languages::<impl prek::config::Language>::run::{{closure}}::{{closure}}
 0.3%   0.6%  85.1KiB              prek prek::languages::<impl prek::config::Language>::install::{{closure}}
 0.3%   0.6%  79.4KiB             prek? <prek::cli::Command as clap_builder::derive::Subcommand>::augment_subcommands
 0.2%   0.4%  49.7KiB              prek prek::run::{{closure}}
 0.2%   0.4%  49.4KiB annotate_snippets annotate_snippets::renderer::render::render
 0.2%   0.3%  44.6KiB              prek prek::cli::run::run::run::{{closure}}
 0.2%   0.3%  43.9KiB             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%  32.0KiB               std core::ptr::drop_in_place<prek::languages::<impl prek::config::Language>::install::{{closure}}>
 0.1%   0.2%  31.8KiB             prek? <prek::cli::RunOptions as clap_builder::derive::Args>::augment_args
 0.1%   0.2%  29.4KiB     granit_parser granit_parser::scanner::Scanner<T>::fetch_more_tokens
 0.1%   0.2%  28.3KiB             prek? <prek::config::_::<impl serde_core::de::Deserialize for prek::config::RemoteHook>::deserialize::__Visitor as serde_core::de::Visitor>::visit_map
 0.1%   0.2%  28.0KiB        aws_lc_sys aws_lc_0_41_0_edwards25519_scalarmuldouble_alt
 0.1%   0.2%  27.5KiB        aws_lc_sys aws_lc_0_41_0_edwards25519_scalarmuldouble
 0.1%   0.2%  26.2KiB              prek prek::cli::try_repo::try_repo::{{closure}}
 0.1%   0.2%  24.8KiB             prek? <prek::config::_::<impl serde_core::de::Deserialize for prek::config::LocalHook>::deserialize::__Visitor as serde_core::de::Visitor>::visit_map
 0.1%   0.2%  22.9KiB     granit_parser granit_parser::scanner::Scanner<T>::fetch_more_tokens
 0.1%   0.2%  22.3KiB         [Unknown] Lp384_montjscalarmul_alt_p384_montjadd
41.8%  86.0%  11.1MiB                   And 24265 smaller methods. Use -n N to show more.
48.6% 100.0%  12.9MiB                   .text section size, the file size is 26.6MiB

[prek-ci-bot]

⚡️ Hyperfine Benchmarks

Summary: 0 regressions, 1 improvements above the 10% threshold.

Environment

• OS: Linux 6.17.0-1018-azure
• CPU: 4 cores
• prek version: prek 0.4.4+45 (760d863 2026-06-13)
• Rust version: rustc 1.96.0 (ac68faa20 2026-05-25)
• 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	3.1	1.02 ± 0.05
prek-head --version	2.3 ± 0.0	2.2	2.5	1.00

prek list

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base list	9.6 ± 0.4	9.2	12.3	1.00 ± 0.05
prek-head list	9.6 ± 0.3	9.2	11.1	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	3.3 ± 0.1	3.2	3.5	1.00
prek-head validate-config .pre-commit-config.yaml	3.3 ± 0.2	3.1	4.3	1.01 ± 0.05

prek sample-config

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base sample-config	2.7 ± 0.1	2.6	2.8	1.01 ± 0.03
prek-head sample-config	2.7 ± 0.1	2.5	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	74.6 ± 2.2	71.5	79.0	1.00
prek-head run --all-files	76.7 ± 2.9	72.3	82.8	1.03 ± 0.05

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

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run --all-files	76.8 ± 3.3	70.8	81.8	1.03 ± 0.06
prek-head run --all-files	74.6 ± 2.6	71.0	80.5	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	75.7 ± 3.3	70.6	82.1	1.02 ± 0.06
prek-head run --all-files	74.2 ± 2.8	69.8	80.6	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	20.6 ± 0.5	19.8	21.7	1.01 ± 0.03
prek-head run trailing-whitespace --all-files	20.4 ± 0.4	19.6	21.2	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 ± 2.2	24.0	30.3	1.03 ± 0.12
prek-head run end-of-file-fixer --all-files	26.5 ± 2.4	23.8	32.9	1.00

prek run check-json --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-json --all-files	8.0 ± 0.2	7.6	8.4	1.00
prek-head run check-json --all-files	8.0 ± 0.3	7.6	8.7	1.00 ± 0.04

prek run check-yaml --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-yaml --all-files	7.7 ± 0.1	7.5	7.9	1.00 ± 0.02
prek-head run check-yaml --all-files	7.7 ± 0.1	7.5	8.0	1.00

prek run check-toml --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-toml --all-files	7.8 ± 0.2	7.5	8.4	1.00
prek-head run check-toml --all-files	7.9 ± 0.2	7.5	8.5	1.01 ± 0.04

prek run check-xml --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run check-xml --all-files	8.0 ± 0.2	7.7	8.4	1.01 ± 0.04
prek-head run check-xml --all-files	7.9 ± 0.2	7.3	8.3	1.00

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

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run detect-private-key --all-files	13.7 ± 1.4	11.9	16.9	1.02 ± 0.13
prek-head run detect-private-key --all-files	13.4 ± 1.1	12.2	16.4	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	18.2 ± 0.7	17.2	19.8	1.00
prek-head run fix-byte-order-marker --all-files	18.4 ± 0.7	17.1	19.9	1.01 ± 0.06

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	1.01 ± 0.01
prek-head install-hooks	4.7 ± 0.0	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 ± 0.0	4.6	4.7	1.00
prek-head install-hooks	4.7 ± 0.1	4.5	4.9	1.01 ± 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	39.2 ± 0.9	38.1	40.8	1.00
prek-head run	39.4 ± 1.0	38.0	41.7	1.00 ± 0.03

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

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run --files '*.json'	8.4 ± 0.2	8.3	9.0	1.01 ± 0.02
prek-head run --files '*.json'	8.4 ± 0.1	8.2	8.5	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	7.1 ± 0.1	7.0	7.3	1.00
prek-head run --dry-run --all-files	7.2 ± 0.1	7.1	7.3	1.01 ± 0.01

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	12.8 ± 0.1	12.6	13.0	1.01 ± 0.01
prek-head run check-hooks-apply --all-files	12.7 ± 0.1	12.6	12.9	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	12.7 ± 0.4	11.3	13.0	1.13 ± 0.04
prek-head run check-useless-excludes --all-files	11.3 ± 0.1	11.2	11.4	1.00

✅ Performance improvement for prek run check-useless-excludes --all-files: 11.2700% faster

prek run identity --all-files

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
prek-base run identity --all-files	10.6 ± 0.1	10.4	10.9	1.01 ± 0.02
prek-head run identity --all-files	10.5 ± 0.1	10.3	10.7	1.00