Remove existing entry if any when materialising symlink #18873
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thejcannon
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May 1, 2023
huonw
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May 1, 2023
…8873) This applies a workaround that fixes pantsbuild#18809, for 2.16: before this PR, repeated commands that write the exact same contents to `dist/` will fail, if those contents include a symlink. After this patch, they will succeed. For instance, `pants export-codegen ::` twice if any codegen creates a symlink. The particular problem of failing when re-materialising an entry only surfaces with symlinks, because directories are created in "exists okay" mode, and files are truncated if they already exist. However, directories and files _do_ have problems when being materialised over an entry of a different kind (pantsbuild#17758), but fixing that seems like a broader issue, and likely too large to target 2.16 at this point. After the change in this PR, we're at least back to the behaviour in 2.15: - directly rerunning commands that write to the workspace will always succeed - rerunning after changes may or may not (and, if it does, may or may not give a valid result: pantsbuild#18849) I've started on a potential fix for pantsbuild#17758 and pantsbuild#18849 in pantsbuild#18871, but, as mentioned, it felt like it was getting too large and too "feature"-y to land for 2.16. If/when a fix along those lines lands, this workaround can likely be reverted.
huonw
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May 2, 2023
#18873) (#18878) This applies a workaround that fixes #18809, for 2.16: before this PR, repeated commands that write the exact same contents to `dist/` will fail, if those contents include a symlink. After this patch, they will succeed. For instance, `pants export-codegen ::` twice if any codegen creates a symlink. The particular problem of failing when re-materialising an entry only surfaces with symlinks, because directories are created in "exists okay" mode, and files are truncated if they already exist. However, directories and files _do_ have problems when being materialised over an entry of a different kind (#17758), but fixing that seems like a broader issue, and likely too large to target 2.16 at this point. After the change in this PR, we're at least back to the behaviour in 2.15: - directly rerunning commands that write to the workspace will always succeed - rerunning after changes may or may not (and, if it does, may or may not give a valid result: #18849) I've started on a potential fix for #17758 and #18849 in #18871, but, as mentioned, it felt like it was getting too large and too "feature"-y to land for 2.16. If/when a fix along those lines lands, this workaround can likely be reverted.
This was referenced May 8, 2023
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This applies a workaround that fixes #18809, for 2.16: before this PR, repeated commands that write the exact same contents to
dist/will fail, if those contents include a symlink. After this patch, they will succeed. For instance,pants export-codegen ::twice if any codegen creates a symlink.The particular problem of failing when re-materialising an entry only surfaces with symlinks, because directories are created in "exists okay" mode, and files are truncated if they already exist.
However, directories and files do have problems when being materialised over an entry of a different kind (#17758), but fixing that seems like a broader issue, and likely too large to target 2.16 at this point. After the change in this PR, we're at least back to the behaviour in 2.15:
pants package ::can corrupt directory target output by leaving stale/deleted contents #18849)I've started on a potential fix for #17758 and #18849 in #18871, but, as mentioned, it felt like it was getting too large and too "feature"-y to land for 2.16. If/when a fix along those lines lands, this workaround can likely be reverted.