[PATCH] bitbake: Correct broken symlink behaviour

[Roman Savchenko <gmstima@gmail.com>]

From: Roman Savchenko <roman.savchenko@attocapital.com>

When making new symlink in case when link name does not exist
possible broken symlink behaviour should be taken into account.

Signed-off-by: Roman Savchenko <gmstima@gmail.com>
---
 bitbake/lib/bb/fetch2/__init__.py | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/bitbake/lib/bb/fetch2/__init__.py b/bitbake/lib/bb/fetch2/__init__.py
index 6ef0c6f..d8a3b96 100644
--- a/bitbake/lib/bb/fetch2/__init__.py
+++ b/bitbake/lib/bb/fetch2/__init__.py
@@ -925,6 +925,17 @@ def rename_bad_checksum(ud, suffix):
     bb.utils.movefile(ud.localpath, new_localpath)
 
 
+def try_symlink(source, link_name):
+    """
+    Tries to make link to passed source if link name does not
+    exist or it is the invalid symlink.
+    """
+    if not os.path.exists(link_name):
+        if os.path.islink(link_name):
+            os.unlink(link_name)
+
+        os.symlink(source, link_name)
+
 def try_mirror_url(fetch, origud, ud, ld, check = False):
     # Return of None or a value means we're finished
     # False means try another url
@@ -962,20 +973,14 @@ def try_mirror_url(fetch, origud, ud, ld, check = False):
                 bb.utils.mkdirhier(os.path.dirname(ud.donestamp))
                 open(ud.donestamp, 'w').close()
             dest = os.path.join(dldir, os.path.basename(ud.localpath))
-            if not os.path.exists(dest):
-                os.symlink(ud.localpath, dest)
+            try_symlink(ud.localpath, dest)
             if not verify_donestamp(origud, ld) or origud.method.need_update(origud, ld):
                 origud.method.download(origud, ld)
                 if hasattr(origud.method,"build_mirror_data"):
                     origud.method.build_mirror_data(origud, ld)
             return origud.localpath
         # Otherwise the result is a local file:// and we symlink to it
-        if not os.path.exists(origud.localpath):
-            if os.path.islink(origud.localpath):
-                # Broken symbolic link
-                os.unlink(origud.localpath)
-
-            os.symlink(ud.localpath, origud.localpath)
+        try_symlink(ud.localpath, origud.localpath)
         update_stamp(origud, ld)
         return ud.localpath
 
-- 
2.7.4