[New Check]: Check for self-assignment leading to blank value

[thesamesam]

Is there an existing such new check request for this?

• I have searched the existing issues

Explain

We want to catch trivial typos like RDEPEND="${RDEPEND}".

Examples

https://github.com/gentoo/gentoo/blob/4a9057157eb7b863d788cd488714a9fa1033d604/games-util/basis_universal/basis_universal-1.16.3.ebuild#L22

# zstd is bundled, see https://github.com/BinomialLLC/basis_universal/pull/228
DEPEND="
	opencl? ( virtual/opencl )
"
RDEPEND="${RDEPEND}" # <--- RDEPEND is now blank, should be RDEPEND="${DEPEND}"

Output message

SuspisciousSelfAssignment

Documentation

Variable is being assigned to itself, blanking the value.

Result level

warning

[thesamesam]

See also:

• Detect invalid/blank/non-existent variable references in variables (e.g. *DEPEND) #262
• Check for likely typos of reserved names #554