hg: obtain lock when creating share from pooled repo (issue5104)
There are race conditions between clients performing a shared clone
to pooled storage:
1) Clients race to create the new shared repo in the pool directory
2) 1 client is seeding the repo in the pool directory and another goes
to share it before it is fully cloned
We prevent these race conditions by obtaining a lock in the pool
directory that is derived from the name of the repo we will be
accessing.
To test this, a simple generic "lockdelay" extension has been added.
The extension inserts an optional, configurable delay before or after
lock acquisition. In the test, we delay 2 seconds after lock acquisition
in the first process and 1 second before lock acquisition in the 2nd
process. This means the first process has 1s to obtain the lock. There
is a race condition here. If we encounter it in the wild, we could
change the dummy extension to wait on the lock file to appear instead
of relying on timing. But that's more complicated. Let's see what
happens first.
Test EOL patching
$ cat >> $HGRCPATH <<EOF
> [diff]
> git = 1
> EOF
Set up helpers
$ seteol () {
> if [ $1 = "LF" ]; then
> EOL='\n'
> else
> EOL='\r\n'
> fi
> }
$ makerepo () {
> seteol $1
> echo
> echo "# ==== setup $1 repository ===="
> echo '% hg init'
> hg init repo
> cd repo
> cat > .hgeol <<EOF
> [repository]
> native = $1
> [patterns]
> unix.txt = LF
> win.txt = CRLF
> **.txt = native
> EOF
> printf "first\r\nsecond\r\nthird\r\n" > win.txt
> printf "first\nsecond\nthird\n" > unix.txt
> printf "first${EOL}second${EOL}third${EOL}" > native.txt
> hg commit --addremove -m 'checkin'
> cd ..
> }
$ dotest () {
> seteol $1
> echo
> echo "% hg clone repo repo-$1"
> hg clone --noupdate repo repo-$1
> cd repo-$1
> cat > .hg/hgrc <<EOF
> [extensions]
> eol =
> [eol]
> native = $1
> EOF
> hg update
> echo '% native.txt'
> cat native.txt
> echo '% unix.txt'
> cat unix.txt
> echo '% win.txt'
> cat win.txt
> printf "first${EOL}third${EOL}" > native.txt
> printf "first\r\nthird\r\n" > win.txt
> printf "first\nthird\n" > unix.txt
> echo '% hg diff'
> hg diff > p
> cat p
> echo '% hg revert'
> hg revert --all
> echo '% hg import'
> hg import -m 'patch' p
> echo '% native.txt'
> cat native.txt
> echo '% unix.txt'
> cat unix.txt
> echo '% win.txt'
> cat win.txt
> echo '% hg diff -c tip'
> hg diff -c tip
> cd ..
> rm -r repo-$1
> }
Run tests
$ makerepo LF
# ==== setup LF repository ====
% hg init
adding .hgeol
adding native.txt
adding unix.txt
adding win.txt
$ dotest LF
% hg clone repo repo-LF
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
% native.txt
first
second
third
% unix.txt
first
second
third
% win.txt
first\r (esc)
second\r (esc)
third\r (esc)
% hg diff
diff --git a/native.txt b/native.txt
--- a/native.txt
+++ b/native.txt
@@ -1,3 +1,2 @@
first
-second
third
diff --git a/unix.txt b/unix.txt
--- a/unix.txt
+++ b/unix.txt
@@ -1,3 +1,2 @@
first
-second
third
diff --git a/win.txt b/win.txt
--- a/win.txt
+++ b/win.txt
@@ -1,3 +1,2 @@
first\r (esc)
-second\r (esc)
third\r (esc)
% hg revert
reverting native.txt
reverting unix.txt
reverting win.txt
% hg import
applying p
% native.txt
first
third
% unix.txt
first
third
% win.txt
first\r (esc)
third\r (esc)
% hg diff -c tip
diff --git a/native.txt b/native.txt
--- a/native.txt
+++ b/native.txt
@@ -1,3 +1,2 @@
first
-second
third
diff --git a/unix.txt b/unix.txt
--- a/unix.txt
+++ b/unix.txt
@@ -1,3 +1,2 @@
first
-second
third
diff --git a/win.txt b/win.txt
--- a/win.txt
+++ b/win.txt
@@ -1,3 +1,2 @@
first\r (esc)
-second\r (esc)
third\r (esc)
$ dotest CRLF
% hg clone repo repo-CRLF
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
% native.txt
first\r (esc)
second\r (esc)
third\r (esc)
% unix.txt
first
second
third
% win.txt
first\r (esc)
second\r (esc)
third\r (esc)
% hg diff
diff --git a/native.txt b/native.txt
--- a/native.txt
+++ b/native.txt
@@ -1,3 +1,2 @@
first
-second
third
diff --git a/unix.txt b/unix.txt
--- a/unix.txt
+++ b/unix.txt
@@ -1,3 +1,2 @@
first
-second
third
diff --git a/win.txt b/win.txt
--- a/win.txt
+++ b/win.txt
@@ -1,3 +1,2 @@
first\r (esc)
-second\r (esc)
third\r (esc)
% hg revert
reverting native.txt
reverting unix.txt
reverting win.txt
% hg import
applying p
% native.txt
first\r (esc)
third\r (esc)
% unix.txt
first
third
% win.txt
first\r (esc)
third\r (esc)
% hg diff -c tip
diff --git a/native.txt b/native.txt
--- a/native.txt
+++ b/native.txt
@@ -1,3 +1,2 @@
first
-second
third
diff --git a/unix.txt b/unix.txt
--- a/unix.txt
+++ b/unix.txt
@@ -1,3 +1,2 @@
first
-second
third
diff --git a/win.txt b/win.txt
--- a/win.txt
+++ b/win.txt
@@ -1,3 +1,2 @@
first\r (esc)
-second\r (esc)
third\r (esc)
$ rm -r repo
$ makerepo CRLF
# ==== setup CRLF repository ====
% hg init
adding .hgeol
adding native.txt
adding unix.txt
adding win.txt
$ dotest LF
% hg clone repo repo-LF
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
% native.txt
first
second
third
% unix.txt
first
second
third
% win.txt
first\r (esc)
second\r (esc)
third\r (esc)
% hg diff
diff --git a/native.txt b/native.txt
--- a/native.txt
+++ b/native.txt
@@ -1,3 +1,2 @@
first\r (esc)
-second\r (esc)
third\r (esc)
diff --git a/unix.txt b/unix.txt
--- a/unix.txt
+++ b/unix.txt
@@ -1,3 +1,2 @@
first
-second
third
diff --git a/win.txt b/win.txt
--- a/win.txt
+++ b/win.txt
@@ -1,3 +1,2 @@
first\r (esc)
-second\r (esc)
third\r (esc)
% hg revert
reverting native.txt
reverting unix.txt
reverting win.txt
% hg import
applying p
% native.txt
first
third
% unix.txt
first
third
% win.txt
first\r (esc)
third\r (esc)
% hg diff -c tip
diff --git a/native.txt b/native.txt
--- a/native.txt
+++ b/native.txt
@@ -1,3 +1,2 @@
first\r (esc)
-second\r (esc)
third\r (esc)
diff --git a/unix.txt b/unix.txt
--- a/unix.txt
+++ b/unix.txt
@@ -1,3 +1,2 @@
first
-second
third
diff --git a/win.txt b/win.txt
--- a/win.txt
+++ b/win.txt
@@ -1,3 +1,2 @@
first\r (esc)
-second\r (esc)
third\r (esc)
$ dotest CRLF
% hg clone repo repo-CRLF
4 files updated, 0 files merged, 0 files removed, 0 files unresolved
% native.txt
first\r (esc)
second\r (esc)
third\r (esc)
% unix.txt
first
second
third
% win.txt
first\r (esc)
second\r (esc)
third\r (esc)
% hg diff
diff --git a/native.txt b/native.txt
--- a/native.txt
+++ b/native.txt
@@ -1,3 +1,2 @@
first\r (esc)
-second\r (esc)
third\r (esc)
diff --git a/unix.txt b/unix.txt
--- a/unix.txt
+++ b/unix.txt
@@ -1,3 +1,2 @@
first
-second
third
diff --git a/win.txt b/win.txt
--- a/win.txt
+++ b/win.txt
@@ -1,3 +1,2 @@
first\r (esc)
-second\r (esc)
third\r (esc)
% hg revert
reverting native.txt
reverting unix.txt
reverting win.txt
% hg import
applying p
% native.txt
first\r (esc)
third\r (esc)
% unix.txt
first
third
% win.txt
first\r (esc)
third\r (esc)
% hg diff -c tip
diff --git a/native.txt b/native.txt
--- a/native.txt
+++ b/native.txt
@@ -1,3 +1,2 @@
first\r (esc)
-second\r (esc)
third\r (esc)
diff --git a/unix.txt b/unix.txt
--- a/unix.txt
+++ b/unix.txt
@@ -1,3 +1,2 @@
first
-second
third
diff --git a/win.txt b/win.txt
--- a/win.txt
+++ b/win.txt
@@ -1,3 +1,2 @@
first\r (esc)
-second\r (esc)
third\r (esc)
$ rm -r repo