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
Test adding .hgeol
$ cat >> $HGRCPATH <<EOF
> [diff]
> git = 1
> EOF
$ seteol () {
> if [ $1 = "LF" ]; then
> EOL='\n'
> else
> EOL='\r\n'
> fi
> }
$ makerepo () {
> echo
> echo "# ==== setup repository ===="
> echo '% hg init'
> hg init repo
> cd repo
> printf "first\nsecond\nthird\n" > a.txt
> hg commit -d '100 0' --addremove -m 'LF commit'
> cd ..
> }
$ dotest () {
> seteol $1
> echo
> echo "% hg clone repo repo-$1"
> hg clone repo repo-$1
> cd repo-$1
> cat > .hg/hgrc <<EOF
> [extensions]
> eol =
> [eol]
> native = LF
> EOF
> cat > .hgeol <<EOF
> [patterns]
> **.txt = native
> [repository]
> native = $1
> EOF
> echo '% hg add .hgeol'
> hg add .hgeol
> echo '% hg status'
> hg status
> echo '% hg commit'
> hg commit -d '200 0' -m 'Added .hgeol file'
> echo '% hg status'
> hg status
> echo '% hg tip -p'
> hg tip -p
> cd ..
> rm -r repo-$1
> }
$ makerepo
# ==== setup repository ====
% hg init
adding a.txt
$ dotest LF
% hg clone repo repo-LF
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
% hg add .hgeol
% hg status
A .hgeol
% hg commit
% hg status
% hg tip -p
changeset: 1:33503edb53b0
tag: tip
user: test
date: Thu Jan 01 00:03:20 1970 +0000
summary: Added .hgeol file
diff --git a/.hgeol b/.hgeol
new file mode 100644
--- /dev/null
+++ b/.hgeol
@@ -0,0 +1,4 @@
+[patterns]
+**.txt = native
+[repository]
+native = LF
$ dotest CRLF
% hg clone repo repo-CRLF
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
% hg add .hgeol
% hg status
M a.txt
A .hgeol
% hg commit
% hg status
% hg tip -p
changeset: 1:6e64eaa9eb23
tag: tip
user: test
date: Thu Jan 01 00:03:20 1970 +0000
summary: Added .hgeol file
diff --git a/.hgeol b/.hgeol
new file mode 100644
--- /dev/null
+++ b/.hgeol
@@ -0,0 +1,4 @@
+[patterns]
+**.txt = native
+[repository]
+native = CRLF
diff --git a/a.txt b/a.txt
--- a/a.txt
+++ b/a.txt
@@ -1,3 +1,3 @@
-first
-second
-third
+first\r (esc)
+second\r (esc)
+third\r (esc)
$ rm -r repo