Windows people: please help check idea for a new Mercurial repository layout

[Adrian Buehlmann]

On 15.06.2008 17:42, Matt Mackall wrote:
> On Sun, 2008-06-15 at 10:48 +0200, Adrian Buehlmann wrote:
> [deleted mostly unread]
> 
> Adrian, chill. I haven't made any sort of decision on what the solution
> is. I've merely suggested that \\?\ is worth considering. In particular
> it might be a good quick hack for people who need something that works
> today.

It's not even that. A simple good quick hack would be to prepend a dot
to every path component and use an additional requires entry.
So Windows folks could get along with Issue793.

Maybe something like this (just a quick hack, very lightly tested):

diff --git a/mercurial/localrepo.py b/mercurial/localrepo.py
--- a/mercurial/localrepo.py
+++ b/mercurial/localrepo.py
@@ -15,7 +15,7 @@

 class localrepository(repo.repository):
     capabilities = util.set(('lookup', 'changegroupsubset'))
-    supported = ('revlogv1', 'store')
+    supported = ('revlogv1', 'store', 'dotpath')

     def __init__(self, parentui, path=None, create=0):
         repo.repository.__init__(self)
@@ -30,7 +30,7 @@
                 if not os.path.exists(path):
                     os.mkdir(path)
                 os.mkdir(self.path)
-                requirements = ["revlogv1"]
+                requirements = ["revlogv1", "dotpath"]
                 if parentui.configbool('format', 'usestore', True):
                     os.mkdir(os.path.join(self.path, "store"))
                     requirements.append("store")
@@ -78,6 +78,11 @@
                 mode = None
         except OSError:
             mode = None
+
+        if "dotpath" in requirements:
+            self.dotpath = util.dotpath
+        else:
+            self.dotpath = lambda p: p

         self._createmode = mode
         self.opener.createmode = mode
@@ -486,7 +491,7 @@
     def file(self, f):
         if f[0] == '/':
             f = f[1:]
-        return filelog.filelog(self.sopener, f)
+        return filelog.filelog(self.sopener, self.dotpath(f))

     def changectx(self, changeid=None):
         return context.changectx(self, changeid)
diff --git a/mercurial/util.py b/mercurial/util.py
--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -905,6 +905,12 @@
         dir = os.path.join(dir, lpart)

     return ''.join(result)
+
+def dotpath(path):
+    '''Encode path to allow storing Windows reserved filenames
+    (e.g. 'nul', 'aux', 'prn', etc.)
+    path must be relative and using '/' as path separator'''
+    return '.' + path.replace('/', '/.')

 def checkexec(path):
     """

"Offcial" Mercurials on such a repo would give:

> hg verify
abort: requirement 'dotpath' not supported!

> What I have decided is that I'm not going to change the repo layout
> twice to fix two different stupid Windows annoyances. Any proposed
> solution must fix both.

If you don't want hashing, then there won't be a repo layout change for
the long paths anyway.

If you don't want to encode reserved filenames, then the shell
will even be unable to delete repos with reserved filenames.

I have just done a short quick scan for explorer alternatives which
might be able to deal with \\?\.. paths. I found none. I suspect
this is because Windows people want to use the recycle bin for deleting
stuff anyway, and that is a shell component again.

So, at least, if you wan't \\?\.. paths, you would have to provide
a command that can delete a repo. Users would then still have to
use hg for copying and backup (clone and bundle).

And you would have to tell them not to drag repos around with
explorer.