check-yaml errors with "too many consecutive comments before resolving collection entry"

[danielhoherd]

Before submitting

• I have searched the issue list for similar bug reports.

Summary

When using pre-commit I do not see an error on a syntactically valid YAML file that contains 89 comment lines in a row, which are used as a template for developers to copy/paste, but with prek I see this error:

  some/valid/file.yaml: Failed to yaml decode (error: line 35 column 5: too many consecutive comments before resolving collection entry
    --> <input>:35:5
     |
  33 |     #              cpu: 500
  34 |     #              memory: 1920
  35 |     #            limits:
     |     ^ too many consecutive comments before resolving collection entry
  36 |     #              cpu: 600
  37 |     #              memory: 2304
     |)

The data structure of the file is like this:

foo:
  bar:
    # First_comment:
    #   88_more_comment_lines:
    Something_else:
       more_stuff: etc..

Platform

linux, macos

Version (current: 0.4.12)

prek 0.4.11 (92ba6c8 2026-07-25)

.pre-commit-config.yaml

repos:
  - repo: https://github.com/pre-commit/pre-commit-hooks
    rev: v6.0.0
    hooks:
      - id: check-yaml

Log file

$ prek -vvv run check-yaml --all-files
2026-08-07T10:06:45-0400
2026-08-07T14:06:45.908746Z DEBUG prek: 0.4.11 (92ba6c8c2 2026-07-25)
2026-08-07T14:06:45.908790Z DEBUG Args: ["prek", "-vvv", "run", "check-yaml", "--all-files"]
2026-08-07T14:06:45.921708Z TRACE get_root: close time.busy=12.9ms time.idle=2.75µs
2026-08-07T14:06:45.921757Z DEBUG Git root: /Users/danielh/a/prek-demo
2026-08-07T14:06:45.921803Z DEBUG Found workspace root at `/Users/danielh/a/prek-demo`
2026-08-07T14:06:45.921822Z TRACE Include selectors: `check-yaml`
2026-08-07T14:06:45.921829Z TRACE Skip selectors: ``
2026-08-07T14:06:45.921863Z DEBUG discover{root="/Users/danielh/a/prek-demo" config=None refresh=false}: Performing fresh workspace discovery
2026-08-07T14:06:45.921896Z TRACE discover{root="/Users/danielh/a/prek-demo" config=None refresh=false}:list_submodules{git_root="/Users/danielh/a/prek-demo"}: close time.busy=2.75µs time.idle=375ns
2026-08-07T14:06:45.923571Z DEBUG Loading project configuration path=.pre-commit-config.yaml
2026-08-07T14:06:45.930322Z TRACE discover{root="/Users/danielh/a/prek-demo" config=None refresh=false}: close time.busy=8.47ms time.idle=1.08µs
2026-08-07T14:06:45.930491Z TRACE Checking lock resource="store" path=/Users/danielh/.cache/prek/.lock
2026-08-07T14:06:45.930524Z DEBUG Acquired lock resource="store"
2026-08-07T14:06:45.933129Z TRACE No requires-python found in pyproject.toml hook=check-yaml
2026-08-07T14:06:45.933186Z TRACE Released lock path=/Users/danielh/.cache/prek/.lock
2026-08-07T14:06:45.933210Z DEBUG Hooks going to run: ["check-yaml"]
2026-08-07T14:06:45.933233Z TRACE ls_files{cwd="/Users/danielh/a/prek-demo"}: Executing `cd /Users/danielh/a/prek-demo && /opt/homebrew/bin/git -c core.useBuiltinFSMonitor=false --literal-pathspecs ls-files -z -- /Users/danielh/a/prek-demo`
2026-08-07T14:06:45.946122Z TRACE ls_files{cwd="/Users/danielh/a/prek-demo"}: close time.busy=493µs time.idle=12.4ms
2026-08-07T14:06:45.946148Z DEBUG All files in the workspace: 1019
2026-08-07T14:06:45.946314Z TRACE Checking lock resource="store" path=/Users/danielh/.cache/prek/.lock
2026-08-07T14:06:45.946327Z DEBUG Acquired lock resource="store"
2026-08-07T14:06:45.951901Z TRACE Executing `/Users/danielh/.local/share/uv/python/cpython-3.14.6-macos-aarch64-none/bin/python3.14 -I -c import sys, json
info = {
    "version": ".".join(map(str, sys.version_info[:3])),
    "base_exec_prefix": sys.base_exec_prefix,
}
print(json.dumps(info))
`
2026-08-07T14:06:45.974118Z TRACE Released lock path=/Users/danielh/.cache/prek/.lock
2026-08-07T14:06:45.974182Z TRACE Files for project `.` after filtered: 1019
2026-08-07T14:06:45.974192Z DEBUG Running priority group with priority 0: ["check-yaml"]
2026-08-07T14:06:45.976467Z TRACE matching_filenames{hook="check-yaml"}: close time.busy=2.26ms time.idle=1.62µs
2026-08-07T14:06:45.976487Z TRACE Files for hook `check-yaml` after filtering matched=true filenames=222
2026-08-07T14:06:45.976501Z DEBUG run{hook_id=check-yaml language=python}: Running hook `check-yaml` in fast path
2026-08-07T14:06:46.028195Z TRACE run{hook_id=check-yaml language=python}: close time.busy=50.4ms time.idle=1.26ms
check yaml...............................................................Failed
- hook id: check-yaml
- duration: 0.05s
- exit code: 1

  test_file.yaml: Failed to yaml decode (error: line 35 column 5: too many consecutive comments before resolving collection entry
    --> <input>:35:5
     |
  33 |     #              cpu: 500
  34 |     #              memory: 1920
  35 |     #            limits:
     |     ^ too many consecutive comments before resolving collection entry
  36 |     #              cpu: 600
  37 |     #              memory: 2304
     |)

[j178]

Thanks for reporting this. I’ve opened an upstream issue: bourumir-wyngs/serde-saphyr#172.