`File name too long` from recursive work directory?

[FFY00]

I am not too sure what is going on here, or what is meant to, as I am fairly new to this tool.

Witth source from https://github.com/lucascolley/cpython/tree/pixi-build

$ rattler-build --version
rattler-build 0.54.0
$ rattler-build debug --recipe=Tools/pixi-packages/asan/recipe.yaml


 ╭─ Finding outputs from recipe
 │ Found 1 variants
 │
 │ Build variant: python-3.15-hb0f4dca_0
 │
 │ ╭─────────────────┬────────────╮
 │ │ Variant         ┆ Version    │
 │ ╞═════════════════╪════════════╡
 │ │ target_platform ┆ "linux-64" │
 │ ╰─────────────────┴────────────╯
 │
 ╰─────────────────── (took 0 seconds)
 Build and/or host environments created for debugging.

 ╭─ Fetching source code
 │ Fetching source from path: /home/anubis/git/cpython
 │
 ╰─────────────────── (took 3 seconds)
Error:   × IO Error: failed to create directory `/home/anubis/git/cpython/output/bld/rattler-build_python_1765385144/work/
  │ output/bld/rattler-build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/
  │ rattler-build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
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  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
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  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
  │ build_python_1765385144/
  │ host_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_place
  │ hold_placehold_placehold_placehold_placehold_placehold_placehold_placehol`: File name too long (os error 36)
  ╰─▶ failed to create directory `/home/anubis/git/cpython/output/bld/rattler-build_python_1765385144/work/output/bld/
      rattler-build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
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      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
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      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
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      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
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      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/work/output/bld/rattler-build_python_1765385144/work/output/bld/rattler-
      build_python_1765385144/
      host_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_pla
      cehold_placehold_placehold_placehold_placehold_placehold_placehold_placehol`: File name too long (os error 36)

[FFY00]

With rattler-build build, it hides the output, but I am guessing it's the same issue.

$ rattler-build build --recipe=Tools/pixi-packages/asan/recipe.yaml

 ╭─ Finding outputs from recipe
 │ Found 1 variants
 │
 │ Build variant: python-3.15-hb0f4dca_0
 │
 │ ╭─────────────────┬────────────╮
 │ │ Variant         ┆ Version    │
 │ ╞═════════════════╪════════════╡
 │ │ target_platform ┆ "linux-64" │
 │ ╰─────────────────┴────────────╯
 │
 ╰─────────────────── (took 0 seconds)

 ╭─ Running build for recipe: python-3.15-hb0f4dca_0
 │
 │ ╭─ Fetching source code
 │ │ Fetching source from path: /home/anubis/git/cpython
 │ │
 │ ╰─────────────────── (took 3 seconds)
 │
 ╰─────────────────── (took 3 seconds)
Error:   × FileSystem error: 'File name too long (os error 36)'

[FFY00]

Looks like this happens when the output directory is inside the source directory 😅

Adding output to .gitignore mitigates the issue, but isn't a long term solution. Having some kind of sentinel file identifying the build directories would be better.

[wenjuno]

I want to add more information to this issue.

1. We run into the issue in our CI after upgrading rattler-build. The reason we need to set output directory inside the source directory is that GitLab CI requires the exported artifact to be inside the project directory.
2. The minimal repo I can come up with is to have a recipe.yaml in a git repo (just git init is sufficient). I think something about being a git repo is triggering the recursive copying. The problem starts showing up since version 0.51.0.
3. It works fine on Windows.

I think this is an unintended regression on Linux. Can someone look into fixing it? Thanks.

[FFY00]

#2046 should fix it 😊