documentation: add some internals documentation about bid merge
This is an important algorithm that was only documented on the wiki so far.
Some update to the algorithm (and associated doc) is to expected in the future
since the bid merge algorithm is bug-ridden when it comes to file deletion comes
to play.
Differential Revision: https://phab.mercurial-scm.org/D8711
$ echo "[extensions]" >> $HGRCPATH
$ echo "largefiles =" >> $HGRCPATH
Create the repository outside $HOME since largefiles write to
$HOME/.cache/largefiles.
$ hg init test
$ cd test
$ echo "root" > root
$ hg add root
$ hg commit -m "Root commit" --config extensions.largefiles=!
Ensure that .hg/largefiles isn't created before largefiles are added
#if unix-permissions
$ chmod 555 .hg
#endif
$ hg status
#if unix-permissions
$ chmod 755 .hg
#endif
$ test -f .hg/largefiles
[1]
$ echo "large" > foo
$ hg add --large foo
$ hg commit -m "Add foo as a largefile"
$ hg update -r 0
getting changed largefiles
0 largefiles updated, 1 removed
0 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ echo "normal" > foo
$ hg add foo
$ hg commit -m "Add foo as normal file"
created new head
Normal file in the working copy, keeping the normal version:
$ echo "n" | hg merge --config ui.interactive=Yes
remote turned local normal file foo into a largefile
use (l)argefile or keep (n)ormal file? n
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg status
$ cat foo
normal
Normal file in the working copy, keeping the largefile version:
$ hg update -q -C
$ echo "l" | hg merge --config ui.interactive=Yes
remote turned local normal file foo into a largefile
use (l)argefile or keep (n)ormal file? l
getting changed largefiles
1 largefiles updated, 0 removed
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg status
M foo
$ hg diff --nodates
diff -r fa129ab6b5a7 .hglf/foo
--- /dev/null
+++ b/.hglf/foo
@@ -0,0 +1,1 @@
+7f7097b041ccf68cc5561e9600da4655d21c6d18
diff -r fa129ab6b5a7 foo
--- a/foo
+++ /dev/null
@@ -1,1 +0,0 @@
-normal
$ cat foo
large
Largefile in the working copy, keeping the normal version:
$ hg update -q -C -r 1
$ echo "n" | hg merge --config ui.interactive=Yes
remote turned local largefile foo into a normal file
keep (l)argefile or use (n)ormal file? n
getting changed largefiles
0 largefiles updated, 0 removed
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg status
M foo
$ hg diff --nodates
diff -r ff521236428a .hglf/foo
--- a/.hglf/foo
+++ /dev/null
@@ -1,1 +0,0 @@
-7f7097b041ccf68cc5561e9600da4655d21c6d18
diff -r ff521236428a foo
--- /dev/null
+++ b/foo
@@ -0,0 +1,1 @@
+normal
$ cat foo
normal
Largefile in the working copy, keeping the largefile version:
$ hg update -q -C -r 1
$ echo "l" | hg merge --config ui.interactive=Yes
remote turned local largefile foo into a normal file
keep (l)argefile or use (n)ormal file? l
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ hg status
$ cat foo
large
Whatever ... commit something so we can invoke merge when updating
$ hg commit -m '3: Merge'
Updating from largefile to normal - no reason to prompt
$ hg up -r 2
getting changed largefiles
0 largefiles updated, 0 removed
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ cat foo
normal
(the update above used to leave the working dir in a very weird state - clean it
$ hg up -qr null
$ hg up -qr 2
)
Updating from normal to largefile - no reason to prompt
$ hg up -r 3
getting changed largefiles
1 largefiles updated, 0 removed
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
$ cat foo
large
$ cd ..
Systematic testing of merges involving largefiles:
Ancestor: normal Parent: normal-id Parent: large result: large
Ancestor: normal Parent: normal2 Parent: large result: ?
Ancestor: large Parent: large-id Parent: normal result: normal
Ancestor: large Parent: large2 Parent: normal result: ?
All cases should try merging both ways.
Prepare test repo:
$ hg init merges
$ cd merges
prepare cases with "normal" ancestor:
$ hg up -qr null
$ echo normal > f
$ hg ci -Aqm "normal-ancestor"
$ hg tag -l "normal-ancestor"
$ touch f2
$ hg ci -Aqm "normal-id"
$ hg tag -l "normal-id"
$ echo normal2 > f
$ hg ci -m "normal2"
$ hg tag -l "normal2"
$ echo normal > f
$ hg ci -Aqm "normal-same"
$ hg tag -l "normal-same"
$ hg up -qr "normal-ancestor"
$ hg rm f
$ echo large > f
$ hg add --large f
$ hg ci -qm "large"
$ hg tag -l "large"
prepare cases with "large" ancestor:
$ hg up -qr null
$ echo large > f
$ hg add --large f
$ hg ci -qm "large-ancestor"
$ hg tag -l "large-ancestor"
$ touch f2
$ hg ci -Aqm "large-id"
$ hg tag -l "large-id"
$ echo large2 > f
$ hg ci -m "large2"
$ hg tag -l "large2"
$ echo large > f
$ hg ci -Aqm "large-same"
$ hg tag -l "large-same"
$ hg up -qr "large-ancestor"
$ hg rm f
$ echo normal > f
$ hg ci -qAm "normal"
$ hg tag -l "normal"
$ hg log -GT '{tags}'
@ normal tip
|
| o large-same
| |
| o large2
| |
| o large-id
|/
o large-ancestor
o large
|
| o normal-same
| |
| o normal2
| |
| o normal-id
|/
o normal-ancestor
Ancestor: normal Parent: normal-id Parent: large result: large
$ hg up -Cqr normal-id
$ hg merge -r large
getting changed largefiles
1 largefiles updated, 0 removed
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat f
large
swap
$ hg up -Cqr large
$ hg merge -r normal-id
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat f
large
Ancestor: normal Parent: normal-same Parent: large result: large
$ hg up -Cqr normal-same
$ hg merge -r large
getting changed largefiles
1 largefiles updated, 0 removed
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat f
large
swap
$ hg up -Cqr large
$ hg merge -r normal-same
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat f
large
Ancestor: normal Parent: normal2 Parent: large result: ?
(annoying extra prompt ... but it do not do any serious harm)
$ hg up -Cqr normal2
$ hg merge -r large
remote turned local normal file f into a largefile
use (l)argefile or keep (n)ormal file? l
getting changed largefiles
1 largefiles updated, 0 removed
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat f
large
$ hg up -Cqr normal2
$ echo n | hg merge -r large --config ui.interactive=Yes
remote turned local normal file f into a largefile
use (l)argefile or keep (n)ormal file? n
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat f
normal2
swap
$ hg up -Cqr large
$ hg merge -r normal2
remote turned local largefile f into a normal file
keep (l)argefile or use (n)ormal file? l
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat f
large
$ hg up -Cqr large
$ echo n | hg merge -r normal2 --config ui.interactive=Yes
remote turned local largefile f into a normal file
keep (l)argefile or use (n)ormal file? n
getting changed largefiles
0 largefiles updated, 0 removed
2 files updated, 0 files merged, 1 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat f
normal2
Ancestor: large Parent: large-id Parent: normal result: normal
$ hg up -Cqr large-id
$ hg merge -r normal
getting changed largefiles
0 largefiles updated, 0 removed
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat f
normal
swap
$ hg up -Cqr normal
$ hg merge -r large-id
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat f
normal
Ancestor: large Parent: large-same Parent: normal result: normal
$ hg up -Cqr large-same
$ hg merge -r normal
getting changed largefiles
0 largefiles updated, 0 removed
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat f
normal
swap
$ hg up -Cqr normal
$ hg merge -r large-same
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat f
normal
Ancestor: large Parent: large2 Parent: normal result: ?
(annoying extra prompt ... but it do not do any serious harm)
$ hg up -Cqr large2
$ hg merge -r normal
remote turned local largefile f into a normal file
keep (l)argefile or use (n)ormal file? l
0 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat f
large2
$ hg up -Cqr large2
$ echo n | hg merge -r normal --config ui.interactive=Yes
remote turned local largefile f into a normal file
keep (l)argefile or use (n)ormal file? n
getting changed largefiles
0 largefiles updated, 0 removed
1 files updated, 0 files merged, 1 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat f
normal
swap
$ hg up -Cqr normal
$ hg merge -r large2
remote turned local normal file f into a largefile
use (l)argefile or keep (n)ormal file? l
getting changed largefiles
1 largefiles updated, 0 removed
2 files updated, 0 files merged, 1 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat f
large2
$ hg up -Cqr normal
$ echo n | hg merge -r large2 --config ui.interactive=Yes
remote turned local normal file f into a largefile
use (l)argefile or keep (n)ormal file? n
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
(branch merge, don't forget to commit)
$ cat f
normal
$ cd ..