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FromAsCasing

frontend/dockerfile/docs/rules/from-as-casing.md

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Output

text
'as' and 'FROM' keywords' casing do not match

Description

While Dockerfile keywords can be either uppercase or lowercase, mixing case styles is not recommended for readability. This rule reports violations where mixed case style occurs for a FROM instruction with an AS keyword declaring a stage name.

Examples

❌ Bad: FROM is uppercase, AS is lowercase.

dockerfile
FROM debian:latest as builder

✅ Good: FROM and AS are both uppercase

dockerfile
FROM debian:latest AS deb-builder

✅ Good: FROM and AS are both lowercase.

dockerfile
from debian:latest as deb-builder