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.
$ . "$TESTDIR/histedit-helpers.sh"
$ cat >> $HGRCPATH <<EOF
> [alias]
> tglog = log -G --template "{rev}:{node}:{phase} '{desc}'\n"
> [extensions]
> histedit=
> [experimental]
> histeditng=True
> 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)
(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 not an edited list candidate
(only use listed changesets)
$ hg --config experimental.histeditng=False histedit 5 --commands - 2>&1 << EOF | fixbundle
> base cd010b8cd998 A
> pick d273e35dcdf2 B
> pick 03772da75548 X
> pick b2f90fd8aa85 I
> pick e8c55b19d366 J
> EOF
hg: parse error: unknown action "base"
$ 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'