handle file URIs correctly, according to RFC 2396 (issue1153)

The new code aims to implement the RFC correctly for file URIs.
Previously they were handled incorrectly in several ways, which
could cause problem on Windows in particular.

mercurial/util.py

@@ -1197,7 +1197,19 b' def drop_scheme(scheme, path):'
     if path.startswith(sc):
         path = path[len(sc):]
         if path.startswith('//'):
-            path = path[2:]
+            if scheme == 'file':
+                i = path.find('/', 2)
+                if i == -1:
+                    return ''
+                # On Windows, absolute paths are rooted at the current drive
+                # root. On POSIX they are rooted at the file system root.
+                if os.name == 'nt':
+                    droot = os.path.splitdrive(os.getcwd())[0] + '/'
+                    path = os.path.join(droot, path[i+1:])
+                else:
+                    path = path[i:]
+            else:
+                path = path[2:]
     return path
 
 def uirepr(s):

tests/test-clone

@@ -44,10 +44,10 b' cd a'
 hg cat a
 
 echo
-echo % "check that we drop the file:// from the path before"
+echo % "check that we drop the file: from the path before"
 echo % "writing the .hgrc"
 cd ../..
-hg clone file://a e
+hg clone file:a e
 grep 'file:' e/.hg/hgrc
 
 echo

tests/test-clone.out

@@ -29,7 +29,7 b' updating to branch default'
 2 files updated, 0 files merged, 0 files removed, 0 files unresolved
 a
 
-% check that we drop the file:// from the path before
+% check that we drop the file: from the path before
 % writing the .hgrc
 updating to branch default
 2 files updated, 0 files merged, 0 files removed, 0 files unresolved

tests/test-pull

@@ -24,3 +24,8 b' cd ..'
 hg init empty
 cd empty
 hg pull -u ../test
+
+echo % test file: uri handling
+hg pull -q file://../test-doesnt-exist
+hg pull -q file:../test
+hg pull -q file://foobar`pwd`/../test

tests/test-pull.out

@@ -30,3 +30,5 b' adding manifests'
 adding file changes
 added 1 changesets with 1 changes to 1 files
 1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+% test file: uri handling
+abort: repository /test-doesnt-exist not found!