List of case and expected behavior when exchanging obsolesence marker

This page is intended for developer

1. Definition

1. You want all markers relevant changeset common between source and destination to be exchanged 2. Marker relevant to a changeset are:

• marker that use this changeset as successors
• prune marker of direct children on this changeset.
• recursive application of the two rules on successors store in those marker

?. What shall we do on partial split push…

    ○ ← a changeset,
    ● ← a changeset that exist remotly before the push.
    ✕ ← pruned changeset
    ø ← obsolete changeset with a precursors
    ◔ ← changeset being pushed
    ◌ ← changeset that does not exist locally but are present in marker history
    ⇠ ← obsolescence marker from that point (if not poiting to anything this mean we do not care about what is point to)

2. A. Simple Case

2.1. A.1 pushing a single heads

2.1.1. A.1.1 pushing a single head

    ⇠◔ A
     |
     ●  O

Marker exist from:

• A

Command run:

• hg push -r A
• hg push

Expected exchange:

• chain from A

2.1.2. A.1.2 pushing a multiple changeset into a single head

     ◔ B
     |
    ⇠◔ A
     |
     ● O

Marker exist from:

• A

Command run:

• hg push -r B
• hg push

Expected exchange:

• chain from A

2.2. A.2 Two heads

     ○ B
  ⇠◔ | A
   |/
   ● O

Marker exist from:

• A

Command run:

• hg push -r A

Expected exchange:

• chain from A

Expected Exclude:

• chain from B

3. A.3 new branch created

  B' ○⇢ø B
     | |
     \Aø⇠◔ A'
      \|/
       ● O

Marker exist from:

• Aø⇠○ A'

• Bø⇠○ B'

Command run:

• hg push -r A

Expected exchange:

• chain from A

Expected Exclude:

• chain from B

Extra node:

* hg push will complain about the new head * hg push should complain about unstable history creation

4. B. Deletion Case

4.1. B.1 Pruned changeset atop the pushed set

    ✕ B
    |
    ◔ A
    |
    ● O

Marker exist from:

• B (prune)

Command run:

• hg push -r A
• hg push

Expected exchange:

• prune marker for B

4.2. B.2 Pruned changeset on head. nothing pushed

    ✕ A
    |
    ● O

Marker exist from:

• A (prune)

Command run:

• hg push -r O
• hg push

Expected exchange:

• prune marker for A

4.3. B.3 Pruned changeset on non-pushed part of the history

  ✕ C
  |
  ○ B
  | ◔ A
  |/
  ● O

Marker exist from:

• C (prune)

Command run:

• hg push -r A
• hg push

Expected exchange:

• ø

Expected Exclude:

• chain from B

4.4. B.4 Pruned changeset on common part of history

  ✕ C
  | ● B
  | |
  | ● A
  |/
  ● O

Marker exist from:

• C (prune)

Command run:

• hg push -r B
• hg push

Expected exchange:

• prune for C

5. C. Advance Case

5.1. C.1 Multiple pruned changeset atop each other

  ✕ B
  |
  ✕ A
  |
  ● O

Marker exist from:

• A (prune)
• B (prune)

Command run:

• hg push -r O
• hg push

Expected exchange:

• A (prune)
• B (prune)

5.2. C.2 Pruned changeset on precursors

  B ✕
    |
  A ø⇠◔ A'
    |/
    ● O

Marker exist from:

• A' succeed to A
• B (prune)

Command run:

• hg push -r A'
• hg push

Expected exchange:

• A ø⇠o A'

• B (prune)

5.3. C.3 Pruned changeset on precursors of another pruned one

  B ✕
    |
  A ø⇠✕ A'
    |/
    ● O

Marker exist from:

• A' succeed to A
• A' (prune
• B (prune)

Command run:

• hg push -r A'
• hg push

Expected exchange:

• A ø⇠✕ A'

• A (prune)
• B (prune)

6. D. Partial Information Case

From then we have changeset missing from the repo but still referenced in obsolescence marker. This has an impact on the knowledge we have from the graph topology.

6.1. D.1 Pruned changeset based on a missing precursors of something we miss

  B ✕
    |
  A ◌⇠◔ A'
    |/
    ● O

Marker exist from:

• A' succeed to A
• B (prune)

Command run:

• hg push -r A'
• hg push

Expected exchange:

• A ø⇠o A'

• B (prune)

7. Z. Crazy case

When I'm note very sure about what we should do

=== Z.1 partial push of split===

   D'○⇢ø D
     | | A
   B ○⇢ø⇠◔ C
      \|/
       ● O

Marker exist from:

• A ø⇠⚭ (B,C) (split)

• D ø⇠○ D'

Command run:

• hg push -r C

Expected exchange:

• We should probably send the whole marker anyway. But what about things related to B children

• A ø⇠⚭ (B,C) (split)

Expected exclude:

• D ø⇠○ D'