view tests/test-newbranch.t @ 29375:fcaf20175b1b

demandimport: delay loading for "from a import b" with absolute_import

Before this patch, "from a import b" doesn't delay loading module "b",
if absolute_import is enabled, even though "from . import b" does.

For example:

  - it is assumed that extension X has "from P import M" for module M
    under package P with absolute_import feature

  - if importing module M is already delayed before loading extension
    X, loading module M in extension X is delayed until actually
    referring

    util, cmdutil, scmutil or so of Mercurial itself should be
    imported by "from . import M" style before loading extension X

  - otherwise, module M is loaded immediately at loading extension X,
    even if extension X itself isn't used at that "hg" command invocation

    Some minor modules (e.g. filemerge or so) of Mercurial itself
    aren't imported by "from . import M" style before loading
    extension X. And of course, external libraries aren't, too.

This might cause startup performance problem of hg command, because
many bundled extensions already enable absolute_import feature.

To delay loading module for "from a import b" with absolute_import
feature, this patch does below in "from a (or .a) import b" with
absolute_import case:

  1. import root module of "name" by system built-in __import__
     (referred as _origimport)

  2. recurse down the module chain for hierarchical "name"

     This logic can be shared with non absolute_import
     case. Therefore, this patch also centralizes it into chainmodules().

  3. and fall through to process elements in "fromlist" for the leaf
     module of "name"

     Processing elements in "fromlist" is executed in the code path
     after "if _pypy: .... else: ..." clause. Therefore, this patch
     replaces "if _pypy:" with "elif _pypy:" to share it.

At 4f1144c3c72b introducing original "work around" for "from a import
b" case, elements in "fromlist" were imported with "level=level". But
"level" might be grater than 1 (e.g. level=2 in "from .. import b"
case) at demandimport() invocation, and importing direct sub-module in
"fromlist" with level grater than 1 causes unexpected result.

IMHO, this seems main reason of "errors for unknown reason" described
in 4f1144c3c72b, and we don't have to worry about it, because this
issue was already fixed by 78d05778907b.

This is reason why this patch removes "errors for unknown reasons"
comment.

  $ branchcache=.hg/cache/branch2

  $ listbranchcaches() {
  >    for f in .hg/cache/branch2*;
  >       do echo === $f ===;
  >       cat $f;
  >     done;
  > }
  $ purgebranchcaches() {
  >     rm .hg/cache/branch2*
  > }

  $ hg init t
  $ cd t

  $ hg branches
  $ echo foo > a
  $ hg add a
  $ hg ci -m "initial"
  $ hg branch foo
  marked working directory as branch foo
  (branches are permanent and global, did you want a bookmark?)
  $ hg branch
  foo
  $ hg ci -m "add branch name"
  $ hg branch bar
  marked working directory as branch bar
  $ hg ci -m "change branch name"

Branch shadowing:

  $ hg branch default
  abort: a branch of the same name already exists
  (use 'hg update' to switch to it)
  [255]

  $ hg branch -f default
  marked working directory as branch default

  $ hg ci -m "clear branch name"
  created new head

There should be only one default branch head

  $ hg heads .
  changeset:   3:1c28f494dae6
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     clear branch name
  
Merging and branches

  $ hg co foo
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg branch
  foo

 set existing branch name fails unless force - setting existing parent branch works without force:

  $ hg branch bar
  abort: a branch of the same name already exists
  (use 'hg update' to switch to it)
  [255]

  $ hg branch -f bar
  marked working directory as branch bar

  $ hg branch foo
  marked working directory as branch foo

  $ echo bleah > a
  $ hg ci -m "modify a branch"

  $ hg merge default
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg branch
  foo

 set existing branch name where branch head is ancestor:

  $ hg branch bar
  abort: a branch of the same name already exists
  (use 'hg update' to switch to it)
  [255]

 set (other) parent branch as branch name

  $ hg branch default
  marked working directory as branch default

 set (first) parent branch as branch name

  $ hg branch foo
  marked working directory as branch foo

  $ hg ci -m "merge"

  $ hg log -G -T '{rev}:{node|short} {branch} {desc}\n'
  @    5:530046499edf foo merge
  |\
  | o  4:adf1a74a7f7b foo modify a branch
  | |
  o |  3:1c28f494dae6 default clear branch name
  | |
  o |  2:c21617b13b22 bar change branch name
  |/
  o  1:6c0e42da283a foo add branch name
  |
  o  0:db01e8ea3388 default initial
  
  $ hg branches
  foo                            5:530046499edf
  default                        3:1c28f494dae6 (inactive)
  bar                            2:c21617b13b22 (inactive)

  $ hg branches -q
  foo
  default
  bar

Test for invalid branch cache:

  $ hg rollback
  repository tip rolled back to revision 4 (undo commit)
  working directory now based on revisions 4 and 3

  $ cp ${branchcache}-served .hg/bc-invalid

  $ hg log -r foo
  changeset:   4:adf1a74a7f7b
  branch:      foo
  tag:         tip
  parent:      1:6c0e42da283a
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     modify a branch
  
  $ cp .hg/bc-invalid $branchcache

  $ hg --debug log -r foo
  changeset:   4:adf1a74a7f7b4cd193d12992f5d0d6a004ed21d6
  branch:      foo
  tag:         tip
  phase:       draft
  parent:      1:6c0e42da283a56b5edc5b4fadb491365ec7f5fa8
  parent:      -1:0000000000000000000000000000000000000000
  manifest:    1:8c342a37dfba0b3d3ce073562a00d8a813c54ffe
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  files:       a
  extra:       branch=foo
  description:
  modify a branch
  
  
  $ purgebranchcaches
  $ echo corrupted > $branchcache

  $ hg log -qr foo
  4:adf1a74a7f7b

  $ listbranchcaches
  === .hg/cache/branch2 ===
  corrupted
  === .hg/cache/branch2-served ===
  adf1a74a7f7b4cd193d12992f5d0d6a004ed21d6 4
  c21617b13b220988e7a2e26290fbe4325ffa7139 o bar
  1c28f494dae69a2f8fc815059d257eccf3fcfe75 o default
  adf1a74a7f7b4cd193d12992f5d0d6a004ed21d6 o foo

Push should update the branch cache:

  $ hg init ../target

Pushing just rev 0:

  $ hg push -qr 0 ../target

  $ (cd ../target/; listbranchcaches)
  === .hg/cache/branch2-base ===
  db01e8ea3388fd3c7c94e1436ea2bd6a53d581c5 0
  db01e8ea3388fd3c7c94e1436ea2bd6a53d581c5 o default

Pushing everything:

  $ hg push -qf ../target

  $ (cd ../target/; listbranchcaches)
  === .hg/cache/branch2-base ===
  adf1a74a7f7b4cd193d12992f5d0d6a004ed21d6 4
  c21617b13b220988e7a2e26290fbe4325ffa7139 o bar
  1c28f494dae69a2f8fc815059d257eccf3fcfe75 o default
  adf1a74a7f7b4cd193d12992f5d0d6a004ed21d6 o foo

Update with no arguments: tipmost revision of the current branch:

  $ hg up -q -C 0
  $ hg up -q
  $ hg id
  1c28f494dae6

  $ hg up -q 1
  $ hg up -q
  $ hg id
  adf1a74a7f7b (foo) tip

  $ hg branch foobar
  marked working directory as branch foobar

  $ hg up
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved

Fast-forward merge:

  $ hg branch ff
  marked working directory as branch ff

  $ echo ff > ff
  $ hg ci -Am'fast forward'
  adding ff

  $ hg up foo
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ hg merge ff
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg branch
  foo
  $ hg commit -m'Merge ff into foo'
  $ hg parents
  changeset:   6:185ffbfefa30
  branch:      foo
  tag:         tip
  parent:      4:adf1a74a7f7b
  parent:      5:1a3c27dc5e11
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     Merge ff into foo
  
  $ hg manifest
  a
  ff


Test merging, add 3 default heads and one test head:

  $ cd ..
  $ hg init merges
  $ cd merges
  $ echo a > a
  $ hg ci -Ama
  adding a

  $ echo b > b
  $ hg ci -Amb
  adding b

  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo c > c
  $ hg ci -Amc
  adding c
  created new head

  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ echo d > d
  $ hg ci -Amd
  adding d
  created new head

  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg branch test
  marked working directory as branch test
  (branches are permanent and global, did you want a bookmark?)
  $ echo e >> e
  $ hg ci -Ame
  adding e

  $ hg log
  changeset:   4:3a1e01ed1df4
  branch:      test
  tag:         tip
  parent:      0:cb9a9f314b8b
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     e
  
  changeset:   3:980f7dc84c29
  parent:      0:cb9a9f314b8b
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     d
  
  changeset:   2:d36c0562f908
  parent:      0:cb9a9f314b8b
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     c
  
  changeset:   1:d2ae7f538514
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     b
  
  changeset:   0:cb9a9f314b8b
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     a
  
Implicit merge with test branch as parent:

  $ hg merge
  abort: branch 'test' has one head - please merge with an explicit rev
  (run 'hg heads' to see all heads)
  [255]
  $ hg up -C default
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

Implicit merge with default branch as parent:

  $ hg merge
  abort: branch 'default' has 3 heads - please merge with an explicit rev
  (run 'hg heads .' to see heads)
  [255]

3 branch heads, explicit merge required:

  $ hg merge 2
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)
  $ hg ci -m merge

2 branch heads, implicit merge works:

  $ hg merge
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ cd ..

We expect that bare update on new branch, updates to parent

  $ hg init bareupdateonnewbranch
  $ cd bareupdateonnewbranch
  $ hg update
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ touch a
  $ hg commit -A -m "a"
  adding a
  $ touch b
  $ hg commit -A -m "b"
  adding b
  $ touch c
  $ hg commit -A -m "c"
  adding c
  $ hg update -r 1
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg log -G
  o  changeset:   2:991a3460af53
  |  tag:         tip
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     c
  |
  @  changeset:   1:0e067c57feba
  |  user:        test
  |  date:        Thu Jan 01 00:00:00 1970 +0000
  |  summary:     b
  |
  o  changeset:   0:3903775176ed
     user:        test
     date:        Thu Jan 01 00:00:00 1970 +0000
     summary:     a
  
  $ hg branch dev
  marked working directory as branch dev
  (branches are permanent and global, did you want a bookmark?)
  $ hg update
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg summary
  parent: 1:0e067c57feba 
   b
  branch: dev
  commit: (new branch)
  update: (current)
  phases: 3 draft

  $ cd ..

We need special handling for repositories with no "default" branch because
"null" revision belongs to non-existent "default" branch.

  $ hg init nodefault
  $ cd nodefault
  $ hg branch -q foo
  $ touch 0
  $ hg ci -Aqm0
  $ touch 1
  $ hg ci -Aqm1
  $ hg update -qr0
  $ hg branch -q bar
  $ touch 2
  $ hg ci -Aqm2
  $ hg update -qr0
  $ hg branch -q baz
  $ touch 3
  $ hg ci -Aqm3
  $ hg ci --close-branch -m 'close baz'
  $ hg update -q null
  $ hg log -GT'{rev} {branch}\n'
  _  4 baz
  |
  o  3 baz
  |
  | o  2 bar
  |/
  | o  1 foo
  |/
  o  0 foo
  

 a) updating from "null" should bring us to the tip-most branch head as
 there is no "default" branch:

  $ hg update -q null
  $ hg id -bn
  -1 default
  $ hg update
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg id -bn
  2 bar

 b) but if we are at uncommitted "default" branch, we should stick to the
 current revision:

  $ hg update -q 0
  $ hg branch default
  marked working directory as branch default
  $ hg id -bn
  0 default
  $ hg update
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg id -bn
  0 default

 c) also, if we have uncommitted branch at "null", we should stick to it:

  $ hg update -q null
  $ hg branch new
  marked working directory as branch new
  $ hg id -bn
  -1 new
  $ hg update
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg id -bn
  -1 new

  $ cd ..

We expect that update --clean discard changes in working directory,
and updates to the head of parent branch.

  $ hg init updatebareclean
  $ cd updatebareclean
  $ hg update --clean
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ touch a
  $ hg commit -A -m "a"
  adding a
  $ touch b
  $ hg commit -A -m "b"
  adding b
  $ touch c
  $ hg commit -A -m "c"
  adding c
  $ hg log
  changeset:   2:991a3460af53
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     c
  
  changeset:   1:0e067c57feba
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     b
  
  changeset:   0:3903775176ed
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     a
  
  $ hg update -r 1
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg branch new-branch
  marked working directory as branch new-branch
  (branches are permanent and global, did you want a bookmark?)
  $ echo "aa" >> a
  $ hg update --clean
  2 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg status
  $ hg branch
  default
  $ hg parent
  changeset:   2:991a3460af53
  tag:         tip
  user:        test
  date:        Thu Jan 01 00:00:00 1970 +0000
  summary:     c
  
We expect that update --clean on non existing parent discards a new branch
and updates to the tipmost non-closed branch head

  $ hg update null
  0 files updated, 0 files merged, 3 files removed, 0 files unresolved
  $ hg branch newbranch
  marked working directory as branch newbranch
  (branches are permanent and global, did you want a bookmark?)
  $ hg update -C
  3 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ hg summary
  parent: 2:991a3460af53 tip
   c
  branch: default
  commit: (clean)
  update: (current)
  phases: 3 draft