simplemerge: stop merging file flags
As
384df4db6520 (merge: merge file flags together with file content,
2013-01-09) explains, we shouldn't do a 3-way merge of the
symlink. However, since
84614212ae39 (flags: actually merge flags in
simplemerge, 2020-05-16), we do that in
`simplemerge.simplemerge()`. What's more, the merging of the
executable flag there isn't actually necessary; it was made a no-op by
the very next commit, i.e.
4234c9af515d (flags: read flag from
dirstate/disk for workingcopyctx (
issue5743), 2020-05-16).
I found the overall flag-merging code (not the bit in
`simplemerge.py`) very hard to follow, but I think I now finally
understand how it works. `mergestate.resolve()` calculates the merged
file flags and sets them on the local side of the merge (confusingly
by calling `_restore_backup()`). Then it calls
`filemerge.filemerge()`, which in turn calls
`simplemerge.simplemerge()` (if premerge is enabled). That means that
the flags on the local side `fcs.flags()` are already correct when the
flag-merging code in `simplemerge.simplemerge()` runs. Interestingly,
that code still works when the local side already has the merged
value, it just doesn't change the value. Here's a truth table to
explain why:
```
BLOMCAR
0000000
0011111
0101011
0111111
1000000
1010000
1100000
1111101
```
B: Base
L: Local
O: Other
M: Merged flags from `mergestate.resolve()`, i.e. what's called "local"
when we get to `simplemerge.simplemerge()`
C: `commonflags` in `simplemerge.simplemerge()`, i.e. `M & O`
A: `addedflags` in `simplemerge.simplemerge()`, i.e. `(M ^ O) - B`
R: Re-merged flags `simplemerge.simplemerge()`, i.e. `C | A`
As you can see, the re-merged flags are always unchanged compared to
the initial merged flags (R equals M).
Therefore, this patch effectively backs out
84614212ae39. (I might
later refactor this code to have the flags explicitly passed in.)
`simplemerge.simplemerge()` is also called from
`contrib/simplemerge.py`, but that code never passes any flags.
Differential Revision: https://phab.mercurial-scm.org/D11879
# Test the plumbing of mq.git option
# Automatic upgrade itself is tested elsewhere.
$ cat <<EOF >> $HGRCPATH
> [extensions]
> mq =
> [diff]
> nodates = 1
> EOF
$ hg init repo-auto
$ cd repo-auto
git=auto: regular patch creation:
$ echo a > a
$ hg add a
$ hg qnew -d '0 0' -f adda
$ cat .hg/patches/adda
# HG changeset patch
# Date 0 0
# Parent 0000000000000000000000000000000000000000
diff -r 000000000000 -r ef8dafc9fa4c a
--- /dev/null
+++ b/a
@@ -0,0 +1,1 @@
+a
git=auto: git patch creation with copy:
$ hg cp a b
$ hg qnew -d '0 0' -f copy
$ cat .hg/patches/copy
# HG changeset patch
# Date 0 0
# Parent ef8dafc9fa4caff80f6e243eb0171bcd60c455b4
diff --git a/a b/b
copy from a
copy to b
git=auto: git patch when using --git:
$ echo regular > regular
$ hg add regular
$ hg qnew -d '0 0' --git -f git
$ cat .hg/patches/git
# HG changeset patch
# Date 0 0
# Parent 99586d5f048c399e20f81cee41fbb3809c0e735d
diff --git a/regular b/regular
new file mode 100644
--- /dev/null
+++ b/regular
@@ -0,0 +1,1 @@
+regular
git=auto: regular patch after qrefresh without --git:
$ hg qrefresh -d '0 0'
$ cat .hg/patches/git
# HG changeset patch
# Date 0 0
# Parent 99586d5f048c399e20f81cee41fbb3809c0e735d
diff -r 99586d5f048c regular
--- /dev/null
+++ b/regular
@@ -0,0 +1,1 @@
+regular
$ cd ..
$ hg init repo-keep
$ cd repo-keep
$ echo '[mq]' > .hg/hgrc
$ echo 'git = KEEP' >> .hg/hgrc
git=keep: git patch with --git:
$ echo a > a
$ hg add a
$ hg qnew -d '0 0' -f --git git
$ cat .hg/patches/git
# HG changeset patch
# Date 0 0
# Parent 0000000000000000000000000000000000000000
diff --git a/a b/a
new file mode 100644
--- /dev/null
+++ b/a
@@ -0,0 +1,1 @@
+a
git=keep: git patch after qrefresh without --git:
$ echo a >> a
$ hg qrefresh -d '0 0'
$ cat .hg/patches/git
# HG changeset patch
# Date 0 0
# Parent 0000000000000000000000000000000000000000
diff --git a/a b/a
new file mode 100644
--- /dev/null
+++ b/a
@@ -0,0 +1,2 @@
+a
+a
$ cd ..
$ hg init repo-yes
$ cd repo-yes
$ echo '[mq]' > .hg/hgrc
$ echo 'git = yes' >> .hg/hgrc
git=yes: git patch:
$ echo a > a
$ hg add a
$ hg qnew -d '0 0' -f git
$ cat .hg/patches/git
# HG changeset patch
# Date 0 0
# Parent 0000000000000000000000000000000000000000
diff --git a/a b/a
new file mode 100644
--- /dev/null
+++ b/a
@@ -0,0 +1,1 @@
+a
git=yes: git patch after qrefresh:
$ echo a >> a
$ hg qrefresh -d '0 0'
$ cat .hg/patches/git
# HG changeset patch
# Date 0 0
# Parent 0000000000000000000000000000000000000000
diff --git a/a b/a
new file mode 100644
--- /dev/null
+++ b/a
@@ -0,0 +1,2 @@
+a
+a
$ cd ..
$ hg init repo-no
$ cd repo-no
$ echo '[diff]' > .hg/hgrc
$ echo 'git = True' >> .hg/hgrc
$ echo '[mq]' > .hg/hgrc
$ echo 'git = False' >> .hg/hgrc
git=no: regular patch with copy:
$ echo a > a
$ hg add a
$ hg qnew -d '0 0' -f adda
$ hg cp a b
$ hg qnew -d '0 0' -f regular
$ cat .hg/patches/regular
# HG changeset patch
# Date 0 0
# Parent ef8dafc9fa4caff80f6e243eb0171bcd60c455b4
diff -r ef8dafc9fa4c -r a70404f79ba3 b
--- /dev/null
+++ b/b
@@ -0,0 +1,1 @@
+a
git=no: regular patch after qrefresh with copy:
$ hg cp a c
$ hg qrefresh -d '0 0'
$ cat .hg/patches/regular
# HG changeset patch
# Date 0 0
# Parent ef8dafc9fa4caff80f6e243eb0171bcd60c455b4
diff -r ef8dafc9fa4c b
--- /dev/null
+++ b/b
@@ -0,0 +1,1 @@
+a
diff -r ef8dafc9fa4c c
--- /dev/null
+++ b/c
@@ -0,0 +1,1 @@
+a
Test how [diff] configuration influence and cause invalid or lossy patches:
$ cat <<EOF >> .hg/hgrc
> [mq]
> git = AUTO
> [diff]
> nobinary = True
> noprefix = True
> showfunc = True
> ignorews = True
> ignorewsamount = True
> ignoreblanklines = True
> unified = 1
> EOF
$ echo ' a' > a
$ hg qnew prepare -d '0 0'
$ echo ' a' > a
$ printf '\0' > b
$ echo >> c
$ hg qnew diff -d '0 0'
$ cat .hg/patches/prepare
# HG changeset patch
# Date 0 0
# Parent cf0bfe72686a47d8d7d7b4529a3adb8b0b449a9f
diff -r cf0bfe72686a -r fb9c4422b0f3 a
--- a/a
+++ b/a
@@ -1,1 +1,1 @@
-a
+ a
$ cat .hg/patches/diff
# HG changeset patch
# Date 0 0
# Parent fb9c4422b0f37dd576522dd9a3f99b825c177efe
diff --git a/a b/a
--- a/a
+++ b/a
@@ -1,1 +1,1 @@
- a
+ a
diff --git a/b b/b
index 78981922613b2afb6025042ff6bd878ac1994e85..f76dd238ade08917e6712764a16a22005a50573d
GIT binary patch
literal 1
Ic${MZ000310RR91
diff --git a/c b/c
--- a/c
+++ b/c
@@ -1,1 +1,2 @@
a
+
$ cd ..