Suppression/Ignore Comments

Beacon supports suppression/ignore comments to selectively disable the formatter, linter, and type checker on specific lines or regions of code.

Formatter Suppressions

Control when the formatter should skip code sections.

Single Line: `# fmt: skip`

Skip formatting for a single statement or line.

# This line will be formatted normally
x = 1

# This line preserves exact spacing
y=2+3  # fmt: skip

# Back to normal formatting
z = 4

Region: `# fmt: off` / `# fmt: on`

Disable formatting for entire code blocks.

# Normal formatting applies here
formatted_dict = {"key": "value"}

# fmt: off
unformatted_dict={"key":"value","no":"spaces"}
complex_expression=1+2+3+4+5+6+7+8+9
# fmt: on

# Back to formatted code
back_to_normal = {"properly": "formatted"}

Multiple # fmt: off/# fmt: on pairs allowed in the same file
Unclosed # fmt: off preserves formatting to end of file
The directive lines themselves are preserved as-is

Alignment Preservation

Common use case: preserving column alignment in matrices or tables.

# Normal list formatting
matrix = [
    [1, 2, 3],
    [4, 5, 6],
]

# fmt: off
# Preserve column alignment
aligned_matrix = [
    [1,    2,    3],
    [100,  200,  300],
    [10,   20,   30],
]
# fmt: on

Linter Suppressions

Suppress specific linter warnings or all warnings on a line.

Suppress All Warnings: `# noqa`

Disable all linter checks for a line.

x = 1  # noqa

Suppress Specific Rules: `# noqa: CODE`

Disable specific linter rules by code.

# Suppress unused import warning
import os  # noqa: BEA015

# Suppress unused variable warning
result = expensive_computation()  # noqa: BEA016

# Suppress multiple specific rules
break  # noqa: BEA005, BEA010

Multiple Rules

Separate multiple rule codes with commas:

# Suppress both undefined name and unused variable
x = undefined_variable  # noqa: BEA001, BEA016

Case Insensitive

Rule codes are case-insensitive:

x = 1  # noqa: bea016  # Same as BEA016

Type Checker Suppressions

Suppress type checking errors.

Suppress All Type Errors: `# type: ignore`

Disable all type checking for a line.

x: int = "string"  # type: ignore

Suppress Specific Error: `# type: ignore[code]`

Disable specific type error categories.

# Suppress only assignment type errors
value: str = 42  # type: ignore[assignment]

# Suppress multiple error types
result: int = some_function()  # type: ignore[assignment, call-arg]

Common type error codes:

assignment - Type mismatch in assignment
arg-type - Incorrect argument type
return-value - Return type mismatch
call-arg - Function call argument errors
attr-defined - Attribute not defined

Combining Suppression/Ignore Comments

Multiple suppression types can be used on the same line in any order

# Suppress both type checker and linter
x: int = "string"  # type: ignore  # noqa: BEA016

# Formatter skip with linter suppression
y=2+3  # fmt: skip  # noqa: BEA020

z = value  # noqa: BEA001  # type: ignore
# Same as:
z = value  # type: ignore  # noqa: BEA001

Quick Reference

Comment	Scope	Applies To	Example
`# fmt: skip`	Single line	Formatter	`x=1 # fmt: skip`
`# fmt: off`	Start region	Formatter	See examples above
`# fmt: on`	End region	Formatter	See examples above
`# noqa`	Single line	All linter rules	`x=1 # noqa`
`# noqa: CODE`	Single line	Specific linter rule(s)	`import os # noqa: BEA015`
`# type: ignore`	Single line	All type errors	`x: int = "s" # type: ignore`
`# type: ignore[code]`	Single line	Specific type error(s)	`x: int = "s" # type: ignore[assignment]`

Beacon.rs