[PATCH] bitbake: Correct broken symlink behaviour

[PATCH] bitbake: Correct broken symlink behaviour

[Roman Savchenko]

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

Unlink broken symlink.

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..a752c6c 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.
+    """
+    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

Re: [PATCH] bitbake: Correct broken symlink behaviour

[Richard Purdie]

Hi,

On Tue, 2016-09-20 at 19:23 +0300, Roman Savchenko wrote:
> From: Roman Savchenko <roman.savchenko@attocapital.com>
> 
> Unlink broken symlink.

This really needs a few more details about the problem and how an issue
occurs. I can understand from reading the patch but not from the commit
message.


> 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..a752c6c 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.
> +    """
> +    if not os.path.exists(link_name):
> +        if os.path.islink(link_name):
> +            os.unlink(link_name)
> +
> +        os.symlink(source, link_name)
> +

I don't think the function name is right. "try" implies its fine if it
doesn't work out. In reality its more like "symlink if its invalid".
"create_valid_symlink" whilst long is probably more reflective of what
it does but I'm sure we could still do better :/. 

You could add "or the symlink is invalid" to the function description
too.

Cheers,

Richard

[PATCH] bitbake: Correct broken symlink behaviour

[Roman Savchenko]

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

Re: [PATCH] bitbake: Correct broken symlink behaviour

[Roman Savchenko]

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Hi Richard,

I adjusted commit message and function description. but I do not agree with
proposed
function name `create_valid_symlink`, becasue link creation could fail - so
I left `try_symlink`
to point this behaviour.

Regards,
Roman

2016-09-23 10:45 GMT+03:00 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
>
>

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Re: [PATCH] bitbake: Correct broken symlink behaviour

[Richard Purdie]

Hi Roman,

On Fri, 2016-09-23 at 10:55 +0300, Roman Savchenko wrote:
> I adjusted commit message and function description. but I do not
> agree with proposed
> function name `create_valid_symlink`, becasue link creation could
> fail - so I left `try_symlink`
> to point this behaviour.

I don't agree with "try_symlink" though, sorry.

Link creation can fail but that is like any other function which can
also fail. We don't prefix all function names with try_ because they
can fail.

We need a better name.

Cheers,

Richard

[PATCH] bitbake: Correct broken symlink behaviour

[Roman Savchenko]

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..6638b34 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 create_symlink_if_not_exist(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)
+            create_symlink_if_not_exist(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)
+        create_symlink_if_not_exist(ud.localpath, origud.localpath)
         update_stamp(origud, ld)
         return ud.localpath
 
-- 
2.7.4

Re: [PATCH] bitbake: Correct broken symlink behaviour

[Roman Savchenko]

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Hi Richard,

I renamed function, probably name is a little bit long, but it fully
displays what it does.

Regards,
Roman.

2016-09-27 13:22 GMT+03:00 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..6638b34 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 create_symlink_if_not_exist(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)
> +            create_symlink_if_not_exist(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)
> +        create_symlink_if_not_exist(ud.localpath, origud.localpath)
>          update_stamp(origud, ld)
>          return ud.localpath
>
> --
> 2.7.4
>
>

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