Means to "explode" priority values to create gaps.

[bhearsum]

This is something I've been musing on, and bhearsum told me to file a bug. (It may not belong in this exact component).

Background:

• our rules are evaluated on a priority integer at present.
• We have rules that can match multiple channels (or even multiple products)
• When gaps close (rules are prior 91, and 90) and you need to put a new rule in between those two, its often difficult, there is a need to edit potentially many rules, and try to reason about which need to be changed, without breaking rule order for other products/channels.

This tool (UI, or manual script, etc) should:

• [Optionally?] take a specified channel or product
• Read in the list of all rules that match.
• Explode the rules priorities, leaving order in tact.

E.g. take the following arbitrary set:

#0 (Template): ::

#1 firefox:beta:96
#2 firefox:beta:95
#3 firefox:beta-cdntest:94
#4 firefox:beta*:93
#5 firefox:beta:92
#6 fennec:beta:92
#7 fennec:beta*:91
#8 firefox:beta:90
#9 <no_product>:beta:89
#10 fennec:release:88
#11 firefox:beta:70

running this script, with the channel/product set to firefox/beta would explode to be like so (unchanged omitted):

#1 firefox:beta:148
#2 firefox:beta:138 # XXX: Should we do 139 to preserve the non-identical prior even though no conflict
#3 firefox:beta-cdntest:138
#4 firefox:beta*:128
#5 firefox:beta:118
#6 fennec:beta:111
#7 fennec:beta*:110
#8 firefox:beta:108
#9 <no_product>:beta:98

Yielding a proper, rule-order-preserving mapping.

Note, since this was "firefox/beta" we still bumped priority for fennec in #6 and #7, and beta-cdntest for firefox in #3 because other matching rules got bumped, and we preserved the existing gap...

The logic of this can be tweaked from my proposal of course.

(Imported from https://bugzilla.mozilla.org/show_bug.cgi?id=1301045)