fix(crontab): avoid panic on env line with empty value#233
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A crontab env line with an empty value (e.g. "FOO=") matched the env regex with an empty value group, and the quote-stripping check indexed envVal[0] unconditionally, panicking with index out of range on the empty string. Guard the quote check on len(envVal) > 0 so an empty assignment parses to an empty value, matching Vixie cron behavior.
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What's broken
ParseCrontabpanics on a crontab that contains an environment line with an empty value, e.g.FOO=— a valid Vixie-cron construct (clearing/setting a variable to empty). Instead of parsing it, supercronic crashes at startup:Why it happens
The env regex
^([^\s=]+)\s*=\s*(.*)$lets the value group match the empty string, soenvVal == "". The quote-stripping block then indexesenvVal[0]unconditionally. The existingFOO=''test doesn't hit this because thereenvValis"''"(length 2) at that point; only a bareFOO=produces a zero-length value.Fix
Guard the quote check with
len(envVal) > 0. Empty values parse to an empty string, consistent with the existingFOO=''behaviour.Test
Added a
FOO=case toTestParseCrontabasserting it parses to{"FOO": ""}; panics before, passes after.