view tests/test-rebase-base.t @ 30776:3997edc4a86d

repair: determine what upgrade will do

This commit introduces code for determining what actions/improvements
an upgrade should perform.

The "upgradefindimprovements" function introduces a mechanism to
return a list of improvements that can be made to a repository.
Each improvement is effectively an action that an upgrade will
perform. Associated with each of these improvements is metadata
that will be used to inform users what's wrong and what an
upgrade will do.

Each "improvement" is categorized as a "deficiency" or an
"optimization." TBH, I'm not thrilled about the terminology and
am receptive to constructive bikeshedding. The main difference
between a "deficiency" and an "optimization" is a deficiency
is always corrected (if it deviates from the current config) and
an "optimization" is an optional action that goes above and beyond
to improve the state of the repository (usually by requiring more
CPU during upgrade).

Our initial set of improvements identifies missing repository
requirements, a single, easily correctable problem with
changelog storage, and a set of "optimizations" related to delta
recalculation.

The main "upgraderepo" function has been expanded to handle
improvements. It queries for the list of improvements and determines
which of them will run based on the current repository state and user

I went through numerous iterations of the output format before
settling on a ReST-inspired definition list format. (I used
bulleted lists in the first submission of this commit and could
not get it to format just right.) Even with the various iterations,
I'm still not super thrilled with the format. But, this is a debug*
command, so that should mean we can refine the output without BC
concerns.

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > rebase=
  > drawdag=$TESTDIR/drawdag.py
  > 
  > [phases]
  > publish=False
  > 
  > [alias]
  > tglog = log -G --template "{rev}: {desc}"
  > EOF

  $ rebasewithdag() {
  >   N=`$PYTHON -c "print($N+1)"`
  >   hg init repo$N && cd repo$N
  >   hg debugdrawdag
  >   hg rebase "$@" > _rebasetmp
  >   r=$?
  >   grep -v 'saved backup bundle' _rebasetmp
  >   [ $r -eq 0 ] && hg tglog
  >   cd ..
  >   return $r
  > }

Single branching point, without merge:

  $ rebasewithdag -b D -d Z <<'EOS'
  >     D E
  >     |/
  > Z B C   # C: branching point, E should be picked
  >  \|/    # B should not be picked
  >   A
  >   |
  >   R
  > EOS
  rebasing 3:d6003a550c2c "C" (C)
  rebasing 5:4526cf523425 "D" (D)
  rebasing 6:b296604d9846 "E" (E tip)
  o  6: E
  |
  | o  5: D
  |/
  o  4: C
  |
  o  3: Z
  |
  | o  2: B
  |/
  o  1: A
  |
  o  0: R
  
Multiple branching points caused by selecting a single merge changeset:

  $ rebasewithdag -b E -d Z <<'EOS'
  >     E
  >    /|
  >   B C D  # B, C: multiple branching points
  >   | |/   # D should not be picked
  > Z | /
  >  \|/
  >   A
  >   |
  >   R
  > EOS
  rebasing 2:c1e6b162678d "B" (B)
  rebasing 3:d6003a550c2c "C" (C)
  rebasing 6:5251e0cb7302 "E" (E tip)
  o    6: E
  |\
  | o  5: C
  | |
  o |  4: B
  |/
  o  3: Z
  |
  | o  2: D
  |/
  o  1: A
  |
  o  0: R
  
Rebase should not extend the "--base" revset using "descendants":

  $ rebasewithdag -b B -d Z <<'EOS'
  >     E
  >    /|
  > Z B C  # descendants(B) = B+E. With E, C will be included incorrectly
  >  \|/
  >   A
  >   |
  >   R
  > EOS
  rebasing 2:c1e6b162678d "B" (B)
  rebasing 5:5251e0cb7302 "E" (E tip)
  o    5: E
  |\
  | o  4: B
  | |
  | o  3: Z
  | |
  o |  2: C
  |/
  o  1: A
  |
  o  0: R
  
Rebase should not simplify the "--base" revset using "roots":

  $ rebasewithdag -b B+E -d Z <<'EOS'
  >     E
  >    /|
  > Z B C  # roots(B+E) = B. Without E, C will be missed incorrectly
  >  \|/
  >   A
  >   |
  >   R
  > EOS
  rebasing 2:c1e6b162678d "B" (B)
  rebasing 3:d6003a550c2c "C" (C)
  rebasing 5:5251e0cb7302 "E" (E tip)
  o    5: E
  |\
  | o  4: C
  | |
  o |  3: B
  |/
  o  2: Z
  |
  o  1: A
  |
  o  0: R
  
The destination is one of the two branching points of a merge:

  $ rebasewithdag -b F -d Z <<'EOS'
  >     F
  >    / \
  >   E   D
  >  /   /
  > Z   C
  >  \ /
  >   B
  >   |
  >   A
  > EOS
  nothing to rebase
  [1]

Multiple branching points caused by multiple bases (issue5420):

  $ rebasewithdag -b E1+E2+C2+B1 -d Z <<'EOS'
  >   Z    E2
  >   |   /
  >   F E1 C2
  >   |/  /
  >   E C1 B2
  >   |/  /
  >   C B1
  >   |/
  >   B
  >   |
  >   A
  >   |
  >   R
  > EOS
  rebasing 3:a113dbaa660a "B1" (B1)
  rebasing 5:06ce7b1cc8c2 "B2" (B2)
  rebasing 6:0ac98cce32d3 "C1" (C1)
  rebasing 8:781512f5e33d "C2" (C2)
  rebasing 9:428d8c18f641 "E1" (E1)
  rebasing 11:e1bf82f6b6df "E2" (E2)
  o  12: E2
  |
  o  11: E1
  |
  | o  10: C2
  | |
  | o  9: C1
  |/
  | o  8: B2
  | |
  | o  7: B1
  |/
  o  6: Z
  |
  o  5: F
  |
  o  4: E
  |
  o  3: C
  |
  o  2: B
  |
  o  1: A
  |
  o  0: R
  
Multiple branching points with multiple merges:

  $ rebasewithdag -b G+P -d Z <<'EOS'
  > G   H   P
  > |\ /|   |\
  > F E D   M N
  >  \|/|  /| |\
  > Z C B I J K L
  >  \|/  |/  |/
  >   A   A   A
  > EOS
  rebasing 2:dc0947a82db8 "C" (C)
  rebasing 8:215e7b0814e1 "D" (D)
  rebasing 9:03ca77807e91 "E" (E)
  rebasing 10:afc707c82df0 "F" (F)
  rebasing 13:018caa673317 "G" (G)
  rebasing 14:4f710fbd68cb "H" (H)
  rebasing 3:08ebfeb61bac "I" (I)
  rebasing 4:a0a5005cec67 "J" (J)
  rebasing 5:83780307a7e8 "K" (K)
  rebasing 6:e131637a1cb6 "L" (L)
  rebasing 11:d6fe3d11d95d "M" (M)
  rebasing 12:fa1e02269063 "N" (N)
  rebasing 15:448b1a498430 "P" (P tip)
  o    15: P
  |\
  | o    14: N
  | |\
  o \ \    13: M
  |\ \ \
  | | | o  12: L
  | | | |
  | | o |  11: K
  | | |/
  | o /  10: J
  | |/
  o /  9: I
  |/
  | o    8: H
  | |\
  | | | o  7: G
  | | |/|
  | | | o  6: F
  | | | |
  | | o |  5: E
  | | |/
  | o |  4: D
  | |\|
  +---o  3: C
  | |
  o |  2: Z
  | |
  | o  1: B
  |/
  o  0: A
  
Slightly more complex merge case (mentioned in https://www.mercurial-scm.org/pipermail/mercurial-devel/2016-November/091074.html):

  $ rebasewithdag -b A3+B3 -d Z <<'EOF'
  > Z     C1    A3     B3
  > |    /     / \    / \
  > M3 C0     A1  A2 B1  B2
  > | /       |   |  |   |
  > M2        M1  C1 C1  M3
  > |
  > M1
  > |
  > M0
  > EOF
  rebasing 4:8817fae53c94 "C0" (C0)
  rebasing 6:06ca5dfe3b5b "B2" (B2)
  rebasing 7:73508237b032 "C1" (C1)
  rebasing 9:fdb955e2faed "A2" (A2)
  rebasing 11:1b2f368c3cb5 "A3" (A3)
  rebasing 10:0a33b0519128 "B1" (B1)
  rebasing 12:bd6a37b5b67a "B3" (B3 tip)
  o    12: B3
  |\
  | o  11: B1
  | |
  | | o    10: A3
  | | |\
  | +---o  9: A2
  | | |
  | o |  8: C1
  | | |
  o | |  7: B2
  | | |
  | o |  6: C0
  |/ /
  o |  5: Z
  | |
  o |  4: M3
  | |
  o |  3: M2
  | |
  | o  2: A1
  |/
  o  1: M1
  |
  o  0: M0
  
Mixed rebasable and non-rebasable bases (unresolved, issue5422):

  $ rebasewithdag -b C+D -d B <<'EOS'
  >   D
  >  /
  > B C
  > |/
  > A
  > EOS
  nothing to rebase
  [1]

Disconnected graph:

  $ rebasewithdag -b B -d Z <<'EOS'
  >   B
  >   |
  > Z A
  > EOS
  nothing to rebase from 112478962961 to 48b9aae0607f
  [1]

Multiple roots. Roots are ancestors of dest:

  $ rebasewithdag -b B+D -d Z <<'EOF'
  > D Z B
  >  \|\|
  >   C A
  > EOF
  rebasing 2:112478962961 "B" (B)
  rebasing 3:b70f76719894 "D" (D)
  o  4: D
  |
  | o  3: B
  |/
  o    2: Z
  |\
  | o  1: C
  |
  o  0: A
  
Multiple roots. One root is not an ancestor of dest:

  $ rebasewithdag -b B+D -d Z <<'EOF'
  > Z B D
  >  \|\|
  >   A C
  > EOF
  nothing to rebase from 86d01f49c0d9+b70f76719894 to 262e37e34f63
  [1]

Multiple roots. One root is not an ancestor of dest. Select using a merge:

  $ rebasewithdag -b E -d Z <<'EOF'
  >   E
  >   |\
  > Z B D
  >  \|\|
  >   A C
  > EOF
  rebasing 2:86d01f49c0d9 "B" (B)
  rebasing 5:539a0ff83ea9 "E" (E tip)
  o    5: E
  |\
  | o    4: B
  | |\
  | | o  3: Z
  | | |
  o | |  2: D
  |/ /
  o /  1: C
   /
  o  0: A
  
Multiple roots. Two children share two parents while dest has only one parent:

  $ rebasewithdag -b B+D -d Z <<'EOF'
  > Z B D
  >  \|\|\
  >   A C A
  > EOF
  rebasing 2:86d01f49c0d9 "B" (B)
  rebasing 3:b7df2ca01aa8 "D" (D)
  o    4: D
  |\
  +---o  3: B
  | |/
  | o  2: Z
  | |
  o |  1: C
   /
  o  0: A