tally/no-trailing-spaces

Disallows trailing whitespace at the end of lines.

Property	Value
Severity	Style
Category	Style
Default	Enabled
Auto-fix	Yes (safe)

Description

Trailing whitespace (spaces and tabs at the end of lines) is invisible noise that clutters diffs in version control. This rule detects and can automatically remove trailing whitespace from all lines in a Dockerfile.

Companion editor configuration

Use EditorConfig integration to configure IDEs and editors to trim trailing whitespace before tally reports it.

Examples

Bad

FROM alpine:3.20···
RUN echo hello··
COPY . /app→

(where · = space, → = tab)

Good

FROM alpine:3.20
RUN echo hello
COPY . /app

Configuration

Default (no config needed):

# Enabled by default with no special options

Skip blank lines that consist entirely of whitespace:

[rules.tally.no-trailing-spaces]
skip-blank-lines = true

Ignore comment lines:

[rules.tally.no-trailing-spaces]
ignore-comments = true

Both options:

[rules.tally.no-trailing-spaces]
skip-blank-lines = true
ignore-comments = true

Options

Option	Type	Default	Description
`skip-blank-lines`	boolean	`false`	Skip lines that are entirely whitespace
`ignore-comments`	boolean	`false`	Skip any line starting with `#` (Dockerfile comments and `#` lines inside heredoc bodies)

Auto-fix

This rule provides a safe auto-fix that removes trailing whitespace from offending lines:

tally lint --fix Dockerfile

Each trailing whitespace occurrence is removed independently, so the fix count equals the number of affected lines.

​Description

​Companion editor configuration

​Examples

​Bad

​Good

​Configuration

​Options

​Auto-fix