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string values with leading hyphenated line cause error when converted to YAML #137
Description
I ran into this issue with psych 1.3.4 with ActiveRecord models where string attributes contained something that 'looks like' YAML.
item = Item.last
item.description = %{- a\n2013-04-08 11:45:33}
item.to_yaml # error
Although the original issue was found in ActiveRecord, it can be shown more generally serializing a Hash:
{ 'key' => %{2013-04-08 11:45:33} }.to_yaml # ok
=> "---\nkey: '2013-04-08 11:45:33'\n"
{ 'key' => %{- 2013-04-08 11:45:33} }.to_yaml # ok
=> "---\nkey: ! '- 2013-04-08 11:45:33'\n"
{ 'key' => %{- a\n2013-04-08 11:45:33} }.to_yaml # error
TypeError: can't convert nil into Integer
from ..gems/psych-1.3.4/lib/psych/scalar_scanner.rb:111:in `utc'
from ..gems/psych-1.3.4/lib/psych/scalar_scanner.rb:111:in `parse_time'
# but if the date format parses correctly, it doesn't fail, but the string has been incorrectly converted to yaml:
{ 'key' => %{- a\n2013-04-08 11:45} }.to_yaml
=> "---\nkey: ! '- a\n\n 2013-04-08 11:45'\n"
It seems like the same date handling error in #82 but the real issue (question?) seems to be that the leading '- string\n' sequence is causing psych to try to interpret my text as yaml when in fact it should all be treated as a string literal.
Is this expected behaviour?
Especially in the ActiveRecord case, can we control such behaviour so that user-generated content doesn't unexpectedly break psych?
Activity
hsbt commentedon Jun 12, 2026
This no longer fails on current releases. The string is dumped as a block literal. Closing as resolved.