Dockerfile/Containerfile formatting issues with for loops/semicolons and `RUN <<EOF`

[jameshearttech]

Recently started using prettier-plugin-sh. Seems to work okay with shell scripts, but I have been struggling with formatting Dockerfile/Containerfile.

Here is the prettier loaded options from the CLI debug.

{
    "plugins":["prettier-plugin-sh"],
    "arrowParens":"avoid",
    "printWidth":100,
    "singleQuote":true,
    "trailingComma":"none",
    "bracketSpacing":true,
    "tabWidth":4,
    "semi":true
}

Here is an example Dockerfile/Containerfile not formatted.

FROM debian:12.6-slim
RUN set -eux; for x in {1..3}; do echo 'foo'; echo 'bar'; echo "$x"; done

Here is what it looks like after formatting.

FROM debian:12.6-slim
RUN set -eux
for x in {1..3}; do
    echo 'foo'
    echo 'bar'
    echo "$x"
done

Here is the output from podman build. Obviously, FOR is not a Dockerfile instruction.

STEP 1/7: FROM debian:12.6-slim
STEP 2/7: RUN set -eux
--> 9816982104ff
STEP 3/7: for x in {1..3}; do
time="2024-07-10T08:01:59-10:00" level=error msg="+(UNHANDLED LOGLEVEL) &imagebuilder.Step{Env:[]string{\"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin\"}, Command:\"for\", Args:[]string{\"\"}, Flags:[]string{}, Attrs:map[string]bool(nil), Message:\"FOR \", Heredocs:[]parser.Heredoc(nil), Original:\"for x in {1..3}; do\"}"
Error: building at STEP "FOR ": Build error: Unknown instruction: "FOR" &imagebuilder.Step{Env:[]string{"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"}, Command:"for", Args:[]string{""}, Flags:[]string{}, Attrs:map[string]bool(nil), Message:"FOR ", Heredocs:[]parser.Heredoc(nil), Original:"for x in {1..3}; do"}

I would rather write RUN <<EOF, but that is also broken by the formatting.

FROM debian:12.6-slim
RUN <<EOF
    set -eux
    for x in {1..3}
    do
        echo 'foo'
        echo 'bar'
        echo "$x"
    done
EOF

Here is what it looks like after formatting.

FROM debian:12.6-slim
RUN << EOF
    set -eux
    for x in {1..3}
    do
        echo 'foo'
        echo 'bar'
        echo "$x"
    done
EOF

The problem here is the space that is added between << and EOF.

STEP 1/10: FROM debian:12.6-slim
STEP 2/10: RUN << EOF
--> 687a1076c4e0
STEP 3/10: set -eux
time="2024-07-10T08:20:19-10:00" level=error msg="+(UNHANDLED LOGLEVEL) &imagebuilder.Step{Env:[]string{\"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin\"}, Command:\"set\", Args:[]string{\"\"}, Flags:[]string{}, Attrs:map[string]bool(nil), Message:\"SET \", Heredocs:[]parser.Heredoc(nil), Original:\"set -eux\"}"
Error: building at STEP "SET ": Build error: Unknown instruction: "SET" &imagebuilder.Step{Env:[]string{"PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"}, Command:"set", Args:[]string{""}, Flags:[]string{}, Attrs:map[string]bool(nil), Message:"SET ", Heredocs:[]parser.Heredoc(nil), Original:"set -eux"}