[python-win32] COM server registering, but getting "The specified module could not be found" on dispatch

[Russell Warren]

On Mon, Dec 17, 2012 at 10:25 PM, Mark Hammond <mhammond at skippinet.com.au>wrote:

> The VS2008 redistributables should probably be in the same directory (ie,
> msvc*90*.dll in system32) or else they might not be loaded.  If you use the
> "depends" tool from MS/sysinternals, you will see both Python itself and
> pythoncom depend on this.
>

I ran the depends tool [1] and sure enough, pythoncom27.dll has 3 missing
dependencies: MSVCR90.DLL; IESHIMS.DLL; and WER.DLL

Screencap with additional errors here:
http://static.inky.ws/image/3530/Selection_249.png

Strangely, you can see in the screencap that MSVCR90.DLL is picked up with
no issues at all by python27.dll (version issues, maybe?!).  Separate
depends analysis of python27.dll does show the other 2 missing.

Actually, assuming you are using a recent pywin32, pycomloader27.dll should
> also exist in that dir and should actually be used internally to load the
> COM object - this was done primarily as a work-around for exactly this
> problem.


Nope - no pycomloader27.dll.  Possibly this has not made it into the latest
ActiveState release?  I'll try a full install from pip.  The only other
python dll was pywintypes27.dll.

What matters is the complexity in how dependent DLLs are loaded - as the
> DLL COM object is loaded by some other app, the rules as applied to that
> app gets used for resolving DLL references.  The COM object as a .exe is
> its own app.


Thanks - I think I get it.  To paraphrase: You're saying that the
dependency issues still exist in the internals of the localserver.py
LocalServer32 implementation, but dependency loading is deferred and there
are no pre-checks.  ie: it may fall flat during runtime at some point when
a dependency is truly needed.  For the inproc version, the windows
internals that are loading the pythoncom27.dll are pre-loading (or
pre-checking) dependencies and crashing before it even gets started.
 Correct?

Thanks very much for the tips.  I'll try and chase down these weird DLL
issues now.

Russ

[1] For anyone else landing here, 'depends' is available here (not
sysinternals): www.dependencywalker.com
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