[PATCH] subrepo: allow remapping subpaths using the "final" path

[Martin Geisler]

# HG changeset patch
# User Martin Geisler <mg at aragost.com>
# Date 1312988370 -7200
# Node ID 4cfdb06e702888cbd4cbe97cf0aec0cb01368456
# Parent  0cb27eda3a1e0ea47a9a0bd5d44f5d21ec4509e1
subrepo: allow remapping subpaths using the "final" path

The way subpath remapping happens now, the right-hand side of a .hgsub
entry is used, as is, to match the left-hand side of a subpaths entry.
The new idea is to expand the .hgsub entry by prefixing the parent
repo path *before* the match occurs - i.e. to operate on the final
path including the parent. For example,

  .hgsub entry:     src/foo = src/foo
  parent repo path: http://example.net/parent
  expansion:        http://example.net/parent/src/foo

The rewriting proceeds like normal on the expanded path. The advantage
of this is more context is available for the rewriting when the
recommended trivial subrepo paths are used in the .hgsub file.

A new option named ui.subpaths-remapping controls this. It has two
values so far:

* "use-intermediate-path", which is the old behavior that applies the
  remapping rules before the expansion with the parent path occurs.
  This is the default.

* "use-final-path", which triggers the new behavior.

diff --git a/mercurial/help/config.txt b/mercurial/help/config.txt
--- a/mercurial/help/config.txt
+++ b/mercurial/help/config.txt
@@ -1080,6 +1080,17 @@
 ``style``
     Name of style to use for command output.
 
+``subpaths-remaping``
+    Controls remapping of relative subrepository paths as per the
+    ``[subpaths]`` section. Relative paths are turned into absolute
+    paths, this setting controls if the rewrite rules are applied
+    before or after this expansion.
+
+    Set to ``use-intermediate-path`` to apply the remapping rules
+    before the expansion with the parent path occurs. This is the
+    default. Set it to ``use-final-path`` to rewrite the final expaned
+    path.
+
 ``timeout``
     The timeout used when a lock is held (in seconds), a negative value
     means no timeout. Default is 600.
diff --git a/mercurial/subrepo.py b/mercurial/subrepo.py
--- a/mercurial/subrepo.py
+++ b/mercurial/subrepo.py
@@ -59,6 +59,12 @@
             kind, src = src.split(']', 1)
             kind = kind[1:]
 
+        if ui.config('ui', 'subpaths-remapping') == 'use-final-path':
+            if not util.url(src).isabs():
+                parent = _abssource(ctx._repo, abort=False)
+                if parent:
+                    src = posixpath.join(parent, src)
+
         for pattern, repl in p.items('subpaths'):
             # Turn r'C:\foo\bar' into r'C:\\foo\\bar' since re.sub
             # does a string decode.
diff --git a/tests/test-subrepo-paths.t b/tests/test-subrepo-paths.t
--- a/tests/test-subrepo-paths.t
+++ b/tests/test-subrepo-paths.t
@@ -1,23 +1,28 @@
   $ hg init outer
   $ cd outer
 
+  $ echo '[paths]' >> .hg/hgrc
+  $ echo 'default = http://example.net/' >> .hg/hgrc
+  $ echo '[ui]' >> .hg/hgrc
+  $ echo 'subpaths-remapping = use-final-path' >> .hg/hgrc
+
 hg debugsub with no remapping
 
-  $ echo 'sub = http://example.net/libfoo' > .hgsub
+  $ echo 'libfoo = libfoo' > .hgsub
   $ hg add .hgsub
 
   $ hg debugsub
-  path sub
+  path libfoo
    source   http://example.net/libfoo
    revision 
 
 hg debugsub with remapping
 
-  $ echo '[subpaths]' > .hg/hgrc
+  $ echo '[subpaths]' >> .hg/hgrc
   $ printf 'http://example.net/lib(.*) = C:\\libs\\\\1-lib\\\n' >> .hg/hgrc
 
   $ hg debugsub
-  path sub
+  path libfoo
    source   C:\libs\foo-lib\
    revision 
 
@@ -26,10 +31,25 @@
   $ echo '[subpaths]' >> $HGRCPATH
   $ echo 'libfoo = libbar' >> $HGRCPATH
   $ hg debugsub
-  path sub
+  path libfoo
    source   C:\libs\bar-lib\
    revision 
 
+test absolute source path -- testing with a URL is important since
+standard os.path.join wont treat that as an absolute path
+
+  $ echo 'abs = http://example.net/abs' > .hgsub
+  $ hg debugsub
+  path abs
+   source   http://example.net/abs
+   revision 
+
+  $ echo 'abs = /abs' > .hgsub
+  $ hg debugsub
+  path abs
+   source   /abs
+   revision 
+
 test bad subpaths pattern
 
   $ cat > .hg/hgrc <<EOF