fix: config:get --shell does not double-escape backslashes in single-quoted output - #3833
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…quoted output
POSIX single-quoted strings treat all characters literally — backslashes
are NOT special and must NOT be escaped. The previous implementation ran
s.replaceAll(/(['\\])/g, String.raw\`\$1\`) on the value before wrapping
it in single quotes, so a literal backslash in a config value (e.g.
foo\nbar) was emitted as 'foo\\nbar', which the shell would interpret as
two characters, not one.
Because the single-quote branch is only reached when the string contains
no single quotes and no newlines, there are no special characters to
escape at all. The fix removes the replaceAll call entirely
(src/lib/config/quote.ts:12).
The corresponding parse() branch had a compensating
replaceAll('\\\\', '\\') to undo the double-escaping; that is also
removed since it is no longer needed and would incorrectly modify strings
that genuinely contain two consecutive backslashes
(src/lib/config/quote.ts:22).
Fixes #1384 (W-23597884)
Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>
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Summary
Bug:
heroku config:get --shelldouble-escapes backslashes inside single-quoted output. A config value likefoo\nbar(one literal backslash) was emitted as'foo\\nbar', which the shell interprets as two backslashes, corrupting the value when the output iseval'd.Root cause:
src/lib/config/quote.ts:12rans.replaceAll(/(['\\])/g, String.raw\$1`)` before wrapping the string in single quotes. POSIX single-quoted strings are fully literal — backslashes have no special meaning and must not be escaped. The single-quote branch is only reached when the string contains no single quotes and no newlines, so there are nothing to escape at all.Fix: Remove the
replaceAllfrom thequote()single-quote branch (src/lib/config/quote.ts:12) and remove the compensatingreplaceAll('\\\\', '\\')from theparse()single-quote branch (src/lib/config/quote.ts:22) that was undoing the double-escaping on read-back.Test: Updated
test/unit/lib/config/quote.test.ts:11to assert the correct (un-escaped) single-quoted output. Roundtrip tests continue to pass.Fixes #1384
Fixes W-23597884
Changes
src/lib/config/quote.tsreplaceAllfrom single-quote branch inquote()src/lib/config/quote.tsreplaceAll('\\\\', '\\')from single-quote branch inparse()test/unit/lib/config/quote.test.tsTest plan
npm test -- --grep quotepasses (quote/parse unit tests including roundtrip)heroku config:set FOO='foo\nbar'theneval $(heroku config:get FOO --shell)yields a single backslash in$FOO🤖 Generated with Claude Code