unison/unison-src/transcripts/diff.md

Things we want to test:

• Diffing identical namespaces
• Adds, removes, updates (with and without metadata updates)
  • Adds with multiple names
  • Adds with multiple names and different metadata on each
• Moved and copied definitions
  • Moves that have more that 1 initial or final name
• ... terms and types
• New patches, modified patches, deleted patches, moved patches
• With and without propagated updates

fromJust = 1
b = 2
bdependent = b
c = 3
helloWorld = '(printLine "Hello, world!")

type A a = A Nat
ability X a1 a2 where x : Nat

.ns1> add
.ns1> alias.term fromJust fromJust'
.ns1> alias.term helloWorld helloWorld2
.ns1> link fromJust b
.ns1> fork .ns1 .ns2
.ns1> cd .
.> diff.namespace ns1 ns2

fromJust = "asldkfjasldkfj"

.ns1b> add
.> merge ns1b ns1

fromJust = 99
b = "oog"
d = 4
e = 5
f = 6
unique type Y a b = Y a b

.ns2> update
.> diff.namespace ns1 ns2
.> alias.term ns2.d ns2.d'
.> alias.type ns2.A ns2.A'
.> alias.type ns2.X ns2.X'
.> diff.namespace ns1 ns2
.> link ns2.f ns1.c
.> diff.namespace ns1 ns2
.> unlink ns2.fromJust ns2.b
.> diff.namespace ns1 ns2
.> alias.type ns1.X ns1.X2
.> alias.type ns2.A' ns2.A''
.> delete.term ns2.fromJust'
.> diff.namespace ns1 ns2
.> diff.namespace ns2 nsempty

Display issues to fixup

• An add with new metadata is getting characterized as an update

• can there be a metadata-only update where it's not a singleton old and new reference

• 12.patch patch needs a space

• This looks like garbage

• Extra 2 blank lines at the end of the add section

• Fix alignment issues with buildTable, convert to column3M (to be written)

• Delete blank line in between copies / renames entries if all entries are 1 to 1 see todo in the code

• Things look screwy when the type signature doesn't fit and has to get broken up into multiple lines. Maybe just disallow that?

• add tagging of propagated updates to test propagated updates output

• adding an alias is showing up as an Add and a Copy; should just show as Copy

• removing one of multiple aliases appears in removes + moves + copies section

  • maybe: anything that's the target of a Move should be filtered out of Removes

    Removes:

    22. ability X2 a1 a2
    

    Moves:

    23. X2     =>     24. X'
    

    Copies:

    25. X  ┐   =>     26. X'
    27. X2 ┘
    

  what about:

  Name changes:

  23. X  ┐  =>  (added)   24. X'
  25. X2 ┘      (removed) 26. X2
  
  23. X was removed
  
  23. X  ┐  =>  24. X'
  25. X2 ┘
  
  24. A     =>   ┌ 25. A'
                 └ 26. A''
  

  {A,A',B}, {A,A',B}

  No change to {A,A',B}

  {A,A',B}, {A,A'}

  B => {} (B was deleted)

  {A,A',B}, {A,A',B,C}

  {A,A',B} => {C} (C was added as a name)

  Proposal:

  Just have one section for all name changes (removes, moves, copies combined) Each item is showing a pair of sets (old names, new names) The old names are just shown in their entirety The added names are new names - old names The removed names are old names - new names Added and removed names are shown on the right, tagged as added or removed

  23. X  ┐  =>  (added)   24. X'
  25. X2 ┘      (removed) 26. X2
  

  Removes:

  11. unique type Y a b
  12. ┌ d  : Nat
  13. └ d'
  12. unique type {Frobnicate,Y} a b
  14. e    : Nat
  15. f    : Nat (+1 metadata)
  16. Y.Y  : a -> b -> Y a b
  
  -- no special case
  23. X     =>  (removed) 24. X
  
  -- special case removal (when RHS is empty set)
  23. X     =>  (removed)
  
  23. X  ┐  =>  (removed)
  25. X2 ┘
  
  23. X     =>  (removed)
  23. X was removed
  
  23. X (removed)  ┐
  25. X2 (removed) ┘
  

  and then "Removes" would mean: the reference no longer exists in the namespace

• some overlapping cases between Moves and Copies^

• Make a decision about how we want to show constructors in the diff

• Maybe don't list the type signature twice for aliases?

  12. ┌ d  : Nat
  13. └ d'