Ambiguous URLs generated for states with optional parameters.

[christopherthielen]

Default parameter values are currently squashed using replace("//", with "/"). Consider how this could be enhanced to guarantee url-to-state-to-url mapping.

[christopherthielen]

Say a state has 3 optional params, fooid, barid, bazid in the url.

.state('test', { 
  url: '/:fooid/:barid/:bazid',
  params: { fooid: 123, barid: 456, bazid: 789 }
}

When navigating to that state with all default parameters, the url generated is /. When refreshing the browser, the router will match the 'test' state and apply the default params. So-far-so-good. However, if you navigate to 'test' with the second or third parameter set, the href generated is ambiguous. $state.go('test', { bazid: 10000 }) generates a url of /10000. It's impossible to determine what param the 10000 value references. (It will be incorrectly matched to fooid in 0.2.11).

Another use case:

.state('parent', { 
  url: '/parent/:parentid',
  params: { parentid: 'foo' }
})
.state('parent.child', {
  url: '/child
});

The url /parent/bar/child correctly maps to parent.child with parentid set to bar. However, we can generate ambiguous URLs between the two states.

$state.go("parent.child") generates /parent/child due to the optional value rules.
$state.go("parent", { parentid: 'child' }) also generates /parent/child.

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The user must be wary of the URLs possibly generated by their state definitions and default values.

We should not allow them to shoot themselves in the foot by default.