fs: normalize encoding before utf8 fast path check#63695
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goingforstudying-ctrl wants to merge 1 commit into
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fs: normalize encoding before utf8 fast path check#63695goingforstudying-ctrl wants to merge 1 commit into
goingforstudying-ctrl wants to merge 1 commit into
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The fs.readFileSync and fs.writeFileSync fast paths for utf8 encoding only checked for 'utf8' and 'utf-8', but normalizeEncoding also accepts 'UTF8' and 'UTF-8'. This meant that using those encodings would bypass the fast path and go through the slower generic path. Fix by normalizing the encoding before checking if it's utf8. Fixes: nodejs#49888
nodejs-github-bot
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mertcanaltin
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Jun 1, 2026
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| const encoding = normalizeEncoding(options.encoding) || options.encoding; | ||
| if (encoding === 'utf8') { |
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| const encoding = normalizeEncoding(options.encoding) || options.encoding; | |
| if (encoding === 'utf8') { | |
| if (options.encoding && normalizeEncoding(options.encoding) === 'utf8') { |
user sended a real utf8 encoding only use fast path, otherwise we return string instead of a buffer, thats add a null condition better
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| const encoding = normalizeEncoding(options.encoding) || options.encoding; | ||
| if (typeof data === 'string' && encoding === 'utf8') { |
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Thanks for pointing that out, lpinca. I was not aware of the earlier PRs. I will close this one in favor of the existing efforts. |
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The fs.readFileSync and fs.writeFileSync fast paths for utf8 encoding only checked for 'utf8' and 'utf-8', but normalizeEncoding also accepts 'UTF8' and 'UTF-8'. This meant that using those encodings would bypass the fast path and go through the slower generic path.
Fix by normalizing the encoding before checking if it's utf8.
Fixes: #49888