scmutil: add file object wrapper class to check ambiguity at closing
In Mercurial source tree, opening a file in "a"/"a+" mode like below
doesn't specify atomictemp=True for vfs, and this avoids file stat
ambiguity check by atomictempfile.
- writing changes out in revlog layer uses "a+" mode
- truncation in repair.strip() uses "a" mode
- truncation in transaction._playback() uses "a" mode
If steps below occurs at "the same time in sec", all of mtime, ctime
and size are same between (1) and (3).
1. append data to revlog-style file (and close transaction)
2. discard appended data by truncation (strip or rollback)
3. append same size but different data to revlog-style file again
Therefore, cache validation doesn't work after (3) as expected.
This patch adds file object wrapper class checkambigatclosing to check
(and get rid of) ambiguity at closing. It is used by vfs in subsequent
patch.
This is a part of ExactCacheValidationPlan.
https://www.mercurial-scm.org/wiki/ExactCacheValidationPlan
BTW, checkambigatclosing is tested in test-filecache.py, even though
it doesn't use filecache itself, because filecache assumes that file
stat ambiguity never occurs (and there is no another test-*.py related
to filecache).
#require execbit
$ cat <<EOF >> $HGRCPATH
> [extensions]
> autodiff = $TESTDIR/autodiff.py
> [diff]
> nodates = 1
> EOF
$ hg init repo
$ cd repo
make a combination of new, changed and deleted file
$ echo regular > regular
$ echo rmregular > rmregular
$ $PYTHON -c "file('bintoregular', 'wb').write('\0')"
$ touch rmempty
$ echo exec > exec
$ chmod +x exec
$ echo rmexec > rmexec
$ chmod +x rmexec
$ echo setexec > setexec
$ echo unsetexec > unsetexec
$ chmod +x unsetexec
$ echo binary > binary
$ $PYTHON -c "file('rmbinary', 'wb').write('\0')"
$ hg ci -Am addfiles
adding binary
adding bintoregular
adding exec
adding regular
adding rmbinary
adding rmempty
adding rmexec
adding rmregular
adding setexec
adding unsetexec
$ echo regular >> regular
$ echo newregular >> newregular
$ rm rmempty
$ touch newempty
$ rm rmregular
$ echo exec >> exec
$ echo newexec > newexec
$ echo bintoregular > bintoregular
$ chmod +x newexec
$ rm rmexec
$ chmod +x setexec
$ chmod -x unsetexec
$ $PYTHON -c "file('binary', 'wb').write('\0\0')"
$ $PYTHON -c "file('newbinary', 'wb').write('\0')"
$ rm rmbinary
$ hg addremove -s 0
adding newbinary
adding newempty
adding newexec
adding newregular
removing rmbinary
removing rmempty
removing rmexec
removing rmregular
git=no: regular diff for all files
$ hg autodiff --git=no
diff -r a66d19b9302d binary
Binary file binary has changed
diff -r a66d19b9302d bintoregular
Binary file bintoregular has changed
diff -r a66d19b9302d exec
--- a/exec
+++ b/exec
@@ -1,1 +1,2 @@
exec
+exec
diff -r a66d19b9302d newbinary
Binary file newbinary has changed
diff -r a66d19b9302d newexec
--- /dev/null
+++ b/newexec
@@ -0,0 +1,1 @@
+newexec
diff -r a66d19b9302d newregular
--- /dev/null
+++ b/newregular
@@ -0,0 +1,1 @@
+newregular
diff -r a66d19b9302d regular
--- a/regular
+++ b/regular
@@ -1,1 +1,2 @@
regular
+regular
diff -r a66d19b9302d rmbinary
Binary file rmbinary has changed
diff -r a66d19b9302d rmexec
--- a/rmexec
+++ /dev/null
@@ -1,1 +0,0 @@
-rmexec
diff -r a66d19b9302d rmregular
--- a/rmregular
+++ /dev/null
@@ -1,1 +0,0 @@
-rmregular
git=yes: git diff for single regular file
$ hg autodiff --git=yes regular
diff --git a/regular b/regular
--- a/regular
+++ b/regular
@@ -1,1 +1,2 @@
regular
+regular
git=auto: regular diff for regular files and non-binary removals
$ hg autodiff --git=auto regular newregular rmregular rmexec
diff -r a66d19b9302d newregular
--- /dev/null
+++ b/newregular
@@ -0,0 +1,1 @@
+newregular
diff -r a66d19b9302d regular
--- a/regular
+++ b/regular
@@ -1,1 +1,2 @@
regular
+regular
diff -r a66d19b9302d rmexec
--- a/rmexec
+++ /dev/null
@@ -1,1 +0,0 @@
-rmexec
diff -r a66d19b9302d rmregular
--- a/rmregular
+++ /dev/null
@@ -1,1 +0,0 @@
-rmregular
$ for f in exec newexec setexec unsetexec binary newbinary newempty rmempty rmbinary bintoregular; do
> echo
> echo '% git=auto: git diff for' $f
> hg autodiff --git=auto $f
> done
% git=auto: git diff for exec
diff -r a66d19b9302d exec
--- a/exec
+++ b/exec
@@ -1,1 +1,2 @@
exec
+exec
% git=auto: git diff for newexec
diff --git a/newexec b/newexec
new file mode 100755
--- /dev/null
+++ b/newexec
@@ -0,0 +1,1 @@
+newexec
% git=auto: git diff for setexec
diff --git a/setexec b/setexec
old mode 100644
new mode 100755
% git=auto: git diff for unsetexec
diff --git a/unsetexec b/unsetexec
old mode 100755
new mode 100644
% git=auto: git diff for binary
diff --git a/binary b/binary
index a9128c283485202893f5af379dd9beccb6e79486..09f370e38f498a462e1ca0faa724559b6630c04f
GIT binary patch
literal 2
Jc${Nk0000200961
% git=auto: git diff for newbinary
diff --git a/newbinary b/newbinary
new file mode 100644
index e69de29bb2d1d6434b8b29ae775ad8c2e48c5391..f76dd238ade08917e6712764a16a22005a50573d
GIT binary patch
literal 1
Ic${MZ000310RR91
% git=auto: git diff for newempty
diff --git a/newempty b/newempty
new file mode 100644
% git=auto: git diff for rmempty
diff --git a/rmempty b/rmempty
deleted file mode 100644
% git=auto: git diff for rmbinary
diff --git a/rmbinary b/rmbinary
deleted file mode 100644
index f76dd238ade08917e6712764a16a22005a50573d..e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
GIT binary patch
literal 0
Hc$@<O00001
% git=auto: git diff for bintoregular
diff --git a/bintoregular b/bintoregular
index f76dd238ade08917e6712764a16a22005a50573d..9c42f2b6427d8bf034b7bc23986152dc01bfd3ab
GIT binary patch
literal 13
Uc$`bh%qz(+N=+}#Ni5<5043uE82|tP
git=warn: regular diff with data loss warnings
$ hg autodiff --git=warn
diff -r a66d19b9302d binary
Binary file binary has changed
diff -r a66d19b9302d bintoregular
Binary file bintoregular has changed
diff -r a66d19b9302d exec
--- a/exec
+++ b/exec
@@ -1,1 +1,2 @@
exec
+exec
diff -r a66d19b9302d newbinary
Binary file newbinary has changed
diff -r a66d19b9302d newexec
--- /dev/null
+++ b/newexec
@@ -0,0 +1,1 @@
+newexec
diff -r a66d19b9302d newregular
--- /dev/null
+++ b/newregular
@@ -0,0 +1,1 @@
+newregular
diff -r a66d19b9302d regular
--- a/regular
+++ b/regular
@@ -1,1 +1,2 @@
regular
+regular
diff -r a66d19b9302d rmbinary
Binary file rmbinary has changed
diff -r a66d19b9302d rmexec
--- a/rmexec
+++ /dev/null
@@ -1,1 +0,0 @@
-rmexec
diff -r a66d19b9302d rmregular
--- a/rmregular
+++ /dev/null
@@ -1,1 +0,0 @@
-rmregular
data lost for: binary
data lost for: bintoregular
data lost for: newbinary
data lost for: newempty
data lost for: newexec
data lost for: rmbinary
data lost for: rmempty
data lost for: setexec
data lost for: unsetexec
git=abort: fail on execute bit change
$ hg autodiff --git=abort regular setexec
abort: losing data for setexec
[255]
git=abort: succeed on regular file
$ hg autodiff --git=abort regular
diff -r a66d19b9302d regular
--- a/regular
+++ b/regular
@@ -1,1 +1,2 @@
regular
+regular
$ cd ..