[tahoe-dev] [tahoe-lafs] #833: reject mutable children when *reading* an immutable dirnode

[tahoe-lafs]

#833: reject mutable children when *reading* an immutable dirnode
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 Reporter:  warner                           |           Owner:  warner  
     Type:  defect                           |          Status:  assigned
 Priority:  critical                         |       Milestone:  1.6.0   
Component:  code-dirnodes                    |         Version:  1.5.0   
 Keywords:  integrity forward-compatibility  |   Launchpad_bug:          
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Comment(by warner):

 For reference, {{{uri.from_string("URI:CHK:<a>look at me I'm evil</a>")}}}
 starts by dispatching on a string prefix: we see the {{{URI:CHK:}}} prefix
 and stop considering anything else (including {{{UnknownURI}}}). Then the
 CHK-specific handler class applies a regexp to the {{{look at me}}} part
 and throws {{{BadURIError}}}.

 The requirement is that any new format we introduce must not share one of
 our previously-claimed prefixes. The prefixes we've defined so far all
 look like {{{/^URI:[A-Z\-]+:/}}}, but I imagine we'll add {{{tahoe://}}}
 or something in the future, and probably some binary formats that will
 also fit into this parse tree because they start with something non-ascii.

 So there's plenty of room for new prefixes, but not room for new shapes on
 current prefixes.

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Ticket URL: <http://allmydata.org/trac/tahoe/ticket/833#comment:18>
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