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view tests/test-revlog-v2.t @ 32979:66117dae87f9
patch: rewrite reversehunks (issue5337)
The old reversehunks code accesses "crecord.uihunk._hunk", which is the raw
recordhunk without crecord selection information, therefore "revert -i"
cannot revert individual lines, aka. issue5337.
The patch rewrites related logic to return the right reverse hunk for
revert. Namely,
1. "fromline" and "toline" are correctly swapped [1]
2. crecord.uihunk generates a correct reverse hunk [2]
Besides, reversehunks(hunks) will no longer modify its input "hunks", which
is more expected.
[1]: To explain why "fromline" and "toline" need to be swapped, take the
following example:
$ cat > a <<EOF
> 1
> 2
> 3
> 4
> EOF
$ cat > b <<EOF
> 2
> 3
> 5
> EOF
$ diff a b
1d0 <---- "1" is "fromline" and "0" is "toline"
< 1 and they are swapped if diff from the reversed direction
4c3 |
< 4 |
--- |
> 5 |
|
$ diff b a |
0a1 <---------+
> 1
3c4 <---- also "4c3" gets swapped to "3c4"
< 5
---
> 4
[2]: This is a bit tricky.
For example, given a file which is empty in working parent but has 3 lines
in working copy, and the user selection:
select hunk to discard
[x] +1
[ ] +2
[x] +3
The user intent is to drop "1" and "3" in working copy but keep "2", so the
reverse patch would be something like:
-1
2 (2 is a "context line")
-3
We cannot just take all selected lines and swap "-" and "+", which will be:
-1
-3
That patch won't apply because of "2". So the correct way is to insert "2"
as a "context line" by inserting it first then deleting it:
-2
+2
Therefore, the correct revert patch is:
-1
-2
+2
-3
It could be reordered to look more like a common diff hunk:
-1
-2
-3
+2
Note: It's possible to return multiple hunks so there won't be lines like
"-2", "+2". But the current implementation is much simpler.
For deletions, like the working parent has "1\n2\n3\n" and it was changed to
empty in working copy:
select hunk to discard
[x] -1
[ ] -2
[x] -3
The user intent is to drop the deletion of 1 and 3 (in other words, keep
those lines), but still delete "2".
The reverse patch is meant to be applied to working copy which is empty.
So the patch would be:
+1
+3
That is to say, there is no need to special handle the unselected "2" like
the above insertion case.
author | Jun Wu <quark@fb.com> |
---|---|
date | Tue, 20 Jun 2017 23:22:38 -0700 |
parents | 19b9fc40cc51 |
children | 351323217fd3 |
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A repo with unknown revlogv2 requirement string cannot be opened $ hg init invalidreq $ cd invalidreq $ echo exp-revlogv2.unknown >> .hg/requires $ hg log abort: repository requires features unknown to this Mercurial: exp-revlogv2.unknown! (see https://mercurial-scm.org/wiki/MissingRequirement for more information) [255] $ cd .. Can create and open repo with revlog v2 requirement $ cat >> $HGRCPATH << EOF > [experimental] > revlogv2 = enable-unstable-format-and-corrupt-my-data > EOF $ hg init empty-repo $ cd empty-repo $ cat .hg/requires dotencode exp-revlogv2.0 fncache store $ hg log Unknown flags to revlog are rejected >>> with open('.hg/store/00changelog.i', 'wb') as fh: ... fh.write('\x00\x04\xde\xad') $ hg log abort: unknown flags (0x04) in version 57005 revlog 00changelog.i! [255] $ cd .. Writing a simple revlog v2 works $ hg init simple $ cd simple $ touch foo $ hg -q commit -A -m initial $ hg log changeset: 0:96ee1d7354c4 tag: tip user: test date: Thu Jan 01 00:00:00 1970 +0000 summary: initial Header written as expected (changelog always disables generaldelta) $ f --hexdump --bytes 4 .hg/store/00changelog.i .hg/store/00changelog.i: 0000: 00 01 de ad |....| $ f --hexdump --bytes 4 .hg/store/data/foo.i .hg/store/data/foo.i: 0000: 00 03 de ad |....|