tests/test-histedit-base.t

localrepo: create new function for instantiating a local repo object

Today, there is a single local repository class - localrepository. Its
__init__ is responsible for loading the .hg/requires file and taking
different actions depending on what is present.

In addition, extensions may define a "reposetup" function that
monkeypatches constructed repository instances, often by implementing
a derived type and changing the __class__ of the repo instance.

Work around alternate storage backends and partial clone has made it
clear to me that shoehorning all this logic into __init__ and operating
on an existing instance is too convoluted. For example, localrepository
assumes revlog storage and swapping in non-revlog storage requires
overriding e.g. file() to return something that isn't a revlog. I've
authored various patches that either:

a) teach various methods (like file()) about different states and
   taking the appropriate code path at run-time
b) create methods/attributes/callables used for instantiating things
   and populating these in __init__

"a" incurs run-time performance penalties and makes code more
complicated since various functions have a bunch of "if storage is X"
branches.

"b" makes localrepository quickly explode in complexity.

My plan for tackling this problem is to make the local repository type
more dynamic. Instead of a static localrepository class/type that
supports all of the local repository configurations (revlogs vs other,
revlogs with ellipsis, revlog v1 versus revlog v2, etc), we'll
dynamically construct a type providing the implementations that are
needed for the repository on disk, derived from the .hg/requires file
and configuration options. The constructed repository type will be
specialized and methods won't need to be taught about different
implementations nor overloaded.

We may also leverage this functionality for building types that don't
implement all attributes. For example, the "intents" feature allows
commands to declare that they are read only. By dynamically
constructing a repository type, we could return a repository instance
with no attributes related to mutating the repository. This could
include things like a "changelog" property implementation that doesn't
check whether it needs to invalidate the hidden revisions set on every
access.

This commit establishes a function for building a local repository
instance. Future commits will start moving functionality from
localrepository.__init__ to this function. Then we'll start dynamically
changing the returned type depending on options that are present.

This change may seem radical. But it should be fully compatible with
the reposetup() model - at least for now.

Differential Revision: https://phab.mercurial-scm.org/D4563

  $ . "$TESTDIR/histedit-helpers.sh"

  $ cat >> $HGRCPATH <<EOF
  > [alias]
  > tglog = log -G --template "{rev}:{node}:{phase} '{desc}'\n"
  > [extensions]
  > histedit=
  > EOF

Create repo a:

  $ hg init a
  $ cd a
  $ hg unbundle "$TESTDIR/bundles/rebase.hg"
  adding changesets
  adding manifests
  adding file changes
  added 8 changesets with 7 changes to 7 files (+2 heads)
  new changesets cd010b8cd998:02de42196ebe (8 drafts)
  (run 'hg heads' to see heads, 'hg merge' to merge)
  $ hg up tip
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved

  $ hg tglog
  @  7:02de42196ebee42ef284b6780a87cdc96e8eaab6:draft 'H'
  |
  | o  6:eea13746799a9e0bfd88f29d3c2e9dc9389f524f:draft 'G'
  |/|
  o |  5:24b6387c8c8cae37178880f3fa95ded3cb1cf785:draft 'F'
  | |
  | o  4:9520eea781bcca16c1e15acc0ba14335a0e8e5ba:draft 'E'
  |/
  | o  3:32af7686d403cf45b5d95f2d70cebea587ac806a:draft 'D'
  | |
  | o  2:5fddd98957c8a54a4d436dfe1da9d87f21a1b97b:draft 'C'
  | |
  | o  1:42ccdea3bb16d28e1848c95fe2e44c000f3f21b1:draft 'B'
  |/
  o  0:cd010b8cd998f3981a5a8115f94f8da4ab506089:draft 'A'
  
Verify that implicit base command and help are listed

  $ HGEDITOR=cat hg histedit |grep base
  #  b, base = checkout changeset and apply further changesets from there

Go to D
  $ hg update 3
  3 files updated, 0 files merged, 2 files removed, 0 files unresolved
edit the history to rebase B onto H


Rebase B onto H
  $ hg histedit 1 --commands - 2>&1 << EOF | fixbundle
  > base 02de42196ebe
  > pick 42ccdea3bb16 B
  > pick 5fddd98957c8 C
  > pick 32af7686d403 D
  > EOF

  $ hg tglog
  @  7:0937e82309df47d14176ee15e45dbec5fbdef340:draft 'D'
  |
  o  6:f778d1cbddac4ab679d9983c9bb92e4c5e09e7fa:draft 'C'
  |
  o  5:3d41b7cc708545206213a842f96d812d2e73d818:draft 'B'
  |
  o  4:02de42196ebee42ef284b6780a87cdc96e8eaab6:draft 'H'
  |
  | o  3:eea13746799a9e0bfd88f29d3c2e9dc9389f524f:draft 'G'
  |/|
  o |  2:24b6387c8c8cae37178880f3fa95ded3cb1cf785:draft 'F'
  | |
  | o  1:9520eea781bcca16c1e15acc0ba14335a0e8e5ba:draft 'E'
  |/
  o  0:cd010b8cd998f3981a5a8115f94f8da4ab506089:draft 'A'
  
Rebase back and drop something
  $ hg histedit 5 --commands - 2>&1 << EOF | fixbundle
  > base cd010b8cd998
  > pick 3d41b7cc7085 B
  > drop f778d1cbddac C
  > pick 0937e82309df D
  > EOF

  $ hg tglog
  @  6:476cc3e4168da2d036b141f7f7dcff7f8e3fe846:draft 'D'
  |
  o  5:d273e35dcdf21a7eb305192ef2e362887cd0a6f8:draft 'B'
  |
  | o  4:02de42196ebee42ef284b6780a87cdc96e8eaab6:draft 'H'
  | |
  | | o  3:eea13746799a9e0bfd88f29d3c2e9dc9389f524f:draft 'G'
  | |/|
  | o |  2:24b6387c8c8cae37178880f3fa95ded3cb1cf785:draft 'F'
  |/ /
  | o  1:9520eea781bcca16c1e15acc0ba14335a0e8e5ba:draft 'E'
  |/
  o  0:cd010b8cd998f3981a5a8115f94f8da4ab506089:draft 'A'
  
Split stack
  $ hg histedit 5 --commands - 2>&1 << EOF | fixbundle
  > base cd010b8cd998
  > pick d273e35dcdf2 B
  > base cd010b8cd998
  > pick 476cc3e4168d D
  > EOF

  $ hg tglog
  @  6:d7a6f907a822c4ce6f15662ae45a42aa46d3818a:draft 'D'
  |
  | o  5:d273e35dcdf21a7eb305192ef2e362887cd0a6f8:draft 'B'
  |/
  | o  4:02de42196ebee42ef284b6780a87cdc96e8eaab6:draft 'H'
  | |
  | | o  3:eea13746799a9e0bfd88f29d3c2e9dc9389f524f:draft 'G'
  | |/|
  | o |  2:24b6387c8c8cae37178880f3fa95ded3cb1cf785:draft 'F'
  |/ /
  | o  1:9520eea781bcca16c1e15acc0ba14335a0e8e5ba:draft 'E'
  |/
  o  0:cd010b8cd998f3981a5a8115f94f8da4ab506089:draft 'A'
  
Abort
  $ echo x > B
  $ hg add B
  $ hg commit -m "X"
  $ hg tglog
  @  7:591369deedfdcbf57471e894999a70d7f676186d:draft 'X'
  |
  o  6:d7a6f907a822c4ce6f15662ae45a42aa46d3818a:draft 'D'
  |
  | o  5:d273e35dcdf21a7eb305192ef2e362887cd0a6f8:draft 'B'
  |/
  | o  4:02de42196ebee42ef284b6780a87cdc96e8eaab6:draft 'H'
  | |
  | | o  3:eea13746799a9e0bfd88f29d3c2e9dc9389f524f:draft 'G'
  | |/|
  | o |  2:24b6387c8c8cae37178880f3fa95ded3cb1cf785:draft 'F'
  |/ /
  | o  1:9520eea781bcca16c1e15acc0ba14335a0e8e5ba:draft 'E'
  |/
  o  0:cd010b8cd998f3981a5a8115f94f8da4ab506089:draft 'A'
  
  $ hg histedit 6 --commands - 2>&1 << EOF | fixbundle
  > base d273e35dcdf2 B
  > drop d7a6f907a822 D
  > pick 591369deedfd X
  > EOF
  merging B
  warning: conflicts while merging B! (edit, then use 'hg resolve --mark')
  Fix up the change (pick 591369deedfd)
  (hg histedit --continue to resume)
  $ hg histedit --abort | fixbundle
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg tglog
  @  7:591369deedfdcbf57471e894999a70d7f676186d:draft 'X'
  |
  o  6:d7a6f907a822c4ce6f15662ae45a42aa46d3818a:draft 'D'
  |
  | o  5:d273e35dcdf21a7eb305192ef2e362887cd0a6f8:draft 'B'
  |/
  | o  4:02de42196ebee42ef284b6780a87cdc96e8eaab6:draft 'H'
  | |
  | | o  3:eea13746799a9e0bfd88f29d3c2e9dc9389f524f:draft 'G'
  | |/|
  | o |  2:24b6387c8c8cae37178880f3fa95ded3cb1cf785:draft 'F'
  |/ /
  | o  1:9520eea781bcca16c1e15acc0ba14335a0e8e5ba:draft 'E'
  |/
  o  0:cd010b8cd998f3981a5a8115f94f8da4ab506089:draft 'A'
  
Continue
  $ hg histedit 6 --commands - 2>&1 << EOF | fixbundle
  > base d273e35dcdf2 B
  > drop d7a6f907a822 D
  > pick 591369deedfd X
  > EOF
  merging B
  warning: conflicts while merging B! (edit, then use 'hg resolve --mark')
  Fix up the change (pick 591369deedfd)
  (hg histedit --continue to resume)
  $ echo b2 > B
  $ hg resolve --mark B
  (no more unresolved files)
  continue: hg histedit --continue
  $ hg histedit --continue | fixbundle
  $ hg tglog
  @  6:03772da75548bb42a8f1eacd8c91d0717a147fcd:draft 'X'
  |
  o  5:d273e35dcdf21a7eb305192ef2e362887cd0a6f8:draft 'B'
  |
  | o  4:02de42196ebee42ef284b6780a87cdc96e8eaab6:draft 'H'
  | |
  | | o  3:eea13746799a9e0bfd88f29d3c2e9dc9389f524f:draft 'G'
  | |/|
  | o |  2:24b6387c8c8cae37178880f3fa95ded3cb1cf785:draft 'F'
  |/ /
  | o  1:9520eea781bcca16c1e15acc0ba14335a0e8e5ba:draft 'E'
  |/
  o  0:cd010b8cd998f3981a5a8115f94f8da4ab506089:draft 'A'
  

base on a previously picked changeset
  $ echo i > i
  $ hg add i
  $ hg commit -m "I"
  $ echo j > j
  $ hg add j
  $ hg commit -m "J"
  $ hg tglog
  @  8:e8c55b19d366b335626e805484110d1d5f6f2ea3:draft 'J'
  |
  o  7:b2f90fd8aa85db5569e3cfc30cd1d7739546368e:draft 'I'
  |
  o  6:03772da75548bb42a8f1eacd8c91d0717a147fcd:draft 'X'
  |
  o  5:d273e35dcdf21a7eb305192ef2e362887cd0a6f8:draft 'B'
  |
  | o  4:02de42196ebee42ef284b6780a87cdc96e8eaab6:draft 'H'
  | |
  | | o  3:eea13746799a9e0bfd88f29d3c2e9dc9389f524f:draft 'G'
  | |/|
  | o |  2:24b6387c8c8cae37178880f3fa95ded3cb1cf785:draft 'F'
  |/ /
  | o  1:9520eea781bcca16c1e15acc0ba14335a0e8e5ba:draft 'E'
  |/
  o  0:cd010b8cd998f3981a5a8115f94f8da4ab506089:draft 'A'
  
  $ hg histedit 5 --commands - 2>&1 << EOF | fixbundle
  > pick d273e35dcdf2 B
  > pick 03772da75548 X
  > base d273e35dcdf2 B
  > pick e8c55b19d366 J
  > base d273e35dcdf2 B
  > pick b2f90fd8aa85 I
  > EOF
  hg: parse error: base "d273e35dcdf2" changeset was an edited list candidate
  (base must only use unlisted changesets)

  $ hg tglog
  @  8:e8c55b19d366b335626e805484110d1d5f6f2ea3:draft 'J'
  |
  o  7:b2f90fd8aa85db5569e3cfc30cd1d7739546368e:draft 'I'
  |
  o  6:03772da75548bb42a8f1eacd8c91d0717a147fcd:draft 'X'
  |
  o  5:d273e35dcdf21a7eb305192ef2e362887cd0a6f8:draft 'B'
  |
  | o  4:02de42196ebee42ef284b6780a87cdc96e8eaab6:draft 'H'
  | |
  | | o  3:eea13746799a9e0bfd88f29d3c2e9dc9389f524f:draft 'G'
  | |/|
  | o |  2:24b6387c8c8cae37178880f3fa95ded3cb1cf785:draft 'F'
  |/ /
  | o  1:9520eea781bcca16c1e15acc0ba14335a0e8e5ba:draft 'E'
  |/
  o  0:cd010b8cd998f3981a5a8115f94f8da4ab506089:draft 'A'