Index: notes/tree-conflicts/use-cases.txt =================================================================== --- notes/tree-conflicts/use-cases.txt (revision 27988) +++ notes/tree-conflicts/use-cases.txt (working copy) @@ -161,7 +161,7 @@ \ |update |commit |commit \ v |(fails) | wcB -- Foo.c' ------------+Bar.c' ------------------------> - (edit) -Foo.c ^ + (edit) -Foo.c' ^ | resolved @@ -230,3 +230,222 @@ | resolved + +========== +USE CASE 4 +========== + +Description + + A file modification is merged onto the source of a file move. + +Current Behavior + + Developer A modifies Foo.c and commits it to the repository. + + Developer B moves Foo.c to Bar.c and commits it to the repository. + + Developer merges A's new revision into his working copy. The merge + will apply A's modification to Foo.c to the Foo.c in B's working + copy. + +Problems With Current Behavior + + First problem: + + A's modification of Foo.c will not be merged to B's line of + development because the merge skips the absent file. + + Second problem: + + B is not explicitly warned about reverting A's modification of Foo.c, + except for a "skipped" warning in the output of the merge command, + which might not be noticed. + +Diagram of current behavior + + + (edit) + urlA -- Foo.c' ------------------> + / (r50) | + / | + -- Foo.c - |merge -c50 + \ |(Foo.c skipped) + \ | + urlB -- +Bar.c ------------|-----------------> + (move) -Foo.c \ | ^ + \ | |commit + \ v |(no-op) + wcB -- Bar.c -- Bar.c ------ --> + + +Desired behavior + + When user B merges, A's modifications to Foo.c should be merged into + Bar.c. Signal a text conflict if necessary. + + A tree conflict should be signalled to inform B of the new changes + to Bar.c, so that B can review the modified Bar.c before committing it. + +Diagram of desired behaviour + + + (edit) + urlA -- Foo.c' ------------------> + / (r50) | + / | + -- Foo.c - |merge -c50 + \ |(tree conflict) + \ | + urlB -- +Bar.c -------------|-------------------- Bar.c' --> + (move) -Foo.c \ | ^ ^ + \ | |commit |commit + \ v |(fails) | + wcB -- Bar.c -- Bar.c' ---------------> + ^ + | + resolved + + +========== +USE CASE 5 +========== + +Description + + A file move is merged onto a modification of the move-source. + + This is essentially the same as Use Case 4, with the difference that + this time, B does the edit and A does the move. + +Current Behavior + + Developer A moves Foo.c to Bar.c and commits it to the repository. + + Developer B modifies Foo.cand commits it to the repository. + + Developer merges A's new revision into his working copy. The merge + will add Bar.c (with the same content as the original Foo.c) and + will delete B's Foo.c. + +Problems With Current Behavior + + First problem: + + B's has modified Foo.c in the past. This modification will be lost + unless B reviews the history of Foo.c and Bar.c at both URLs and + corrects the problem (e.g., via 'svn copy'). + +Diagram of current behavior + + + (move) + urlA -- +Bar.c -------------------> + / -Foo.c | + / (r50) | + -- Foo.c - |merge -c50 + \ | + \ | + urlB -- Foo.c' -------------|------------ Bar.c ---> + (edit) \ | ^ + \ | |commit + \ v | + wcB -- Foo.c' -- +Bar.c ------> + -Foo.c' + + +Desired behavior + + In B's working copy, the update should add Bar.c and merge the local + modifications to Foo.c into Bar.c. Signal a text conflict if necessary. + + Foo.c should be deleted from B's working copy. + + A tree conflict should be signaled to inform B that Foo.c has been + renamed to Bar.c + +Diagram of desired behaviour + + + (move) + urlA -- +Bar.c -------------------> + / -Foo.c | + / (r50) | + -- Foo.c - |merge -c50 + \ |(tree conflict) + \ | + urlB -- Foo.c' -------------|-------------------- Bar.c'--> + (edit) \ | ^ ^ + \ | |commit |commit + \ v |(fails) | + wcB -- Foo.c' -- Bar.c' ---------------> + -Foo.c' ^ + | + resolved + + +========== +USE CASE 6 +========== + +Description + + A file move is merged onto a conflicting file move. + +Current Behavior + + Developer A moves Foo.c to Bar.c and commits it to the repository. + + Developer B moves Foo.c to Bix.c and commits it to the repository. + + Developer merges A's new revision into his working copy. The merge + will add Bar.c with history in B's working copy. + +Problems With Current Behavior + + After B's next commit, the content of the original Foo.c will exist + twice in the source tree under two different paths (Bar.c and + Bix.c). This may not have been intended. + +Diagram of current behavior + + + (edit) + urlA -- +Bar.c ------------------> + / -Foo.c | + / (r50) | + -- Foo.c - |merge -c50 + \ | + \ | + urlB -- +Bix.c ------------|---------------- Bix.c ---> + (move) -Foo.c \ | ^ Bar.c + \ | |commit + \ v | + wcB -- Bix.c -- Bix.c ----------> + +Bar.c + + +Desired behavior + + A tree conflict should be signaled to inform B of the conflicting + rename operation. B can delete either file or commit both. + +Diagram of desired behaviour + + + (edit) + urlA -- +Bar.c -----------------> + / -Foo.c | + / (r50) | + -- Foo.c - |merge -c50 + \ |(tree conflict) + \ | + urlB -- +Bix.c ------------|------------------------- Bar.c --> + (move) -Foo.c \ | ^ ^ (or Bix.c, + \ | |commit |commit or both) + \ v |(fails) | + wcB -- Bix.c -- Bix.c --------------> + +Bar.c ^ + | + resolved +