fix(engine): prevent Files.Lines panic on empty file (backport to v3) - #32303
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TerryHowe merged 1 commit intoJul 28, 2026
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Files.Lines guards against a nil entry but an empty file inside a chart is stored as a non-nil zero-length byte slice, so the trailing newline check indexes s[-1] and panics. The engine recovers the panic into a render error, making every template/install/upgrade/lint that references the file fail. Extend the guard to len(f[path]) == 0 and return an empty slice, matching the behaviour for missing files. Fixes helm#32279 Signed-off-by: Mahesh Sadupalli <mahesh.sadupalli@gmail.com>
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Promptless prepared a documentation update related to this change. Triggered by helm/helm PR #32303 This PR fixes a user-visible panic in the |
gjenkins8
approved these changes
Jul 27, 2026
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Backport of #32290 to
dev-v3.Problem
Files.Linesguards against a nil entry (f[path] == nil) but an empty file inside a chart archive is stored as a non-nil zero-length[]byte. The guard passes, the code then indexess[len(s)-1]to strip a trailing newline, and panics with an index-out-of-range. The engine recovers the panic into a render error, so everyhelm install,helm upgrade, orhelm lintthat references an empty file with{{ .Files.Lines ... }}fails.Fix
Change the guard from
f[path] == niltolen(f[path]) == 0, returning an empty slice for both missing and empty files (matching the documented behaviour for missing files).Tests
Three new table-driven cases:
"")"\n")[""]— one empty elementTests verified red on unfixed code (panic recovered as "index out of range"), green on fixed code.
Relation to main
This is a direct cherry-pick of the same commit from #32290 (targeting
main). Cherry-pick applied cleanly with no conflicts. Requested as a v3 backport because the v3 bug-fix window closes today (8 July 2026).