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'md5sum' object is changed automatically.

asked 2020-03-31 01:54:23 -0500

Ros_junior gravatar image

updated 2020-03-31 02:09:30 -0500

Hi, I have a trouble with md5sum issue.
I have built two packages in roscpp and rosjave and both are connected with rossrv.
In order to implement, I defined made a new package for defining .srv file for a new message types.

When I added another message file in the same package, the problem comes to .

Suppose my .srv file name is perception.srv,
when I comment like $rossrv md5 perception in console, it shows md5sum as 9d5d0f603573839f746e2437bd9a65b9.

If I added another message file in the same package and compiled it, however, the md5sum of perception.srv is changed and shows c628b5aaf5972bd40247658d5e46eebf.

I want to know why it is changed like this and how to recover its original md5sum.

(p.s) Both packages, rosjava and roscpp, are in the same machine and also the message pacakage either. Even I have tried to remove devel,build files and rebuild catkin_ws, nothing helpful.

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$ rossrv md5 perception

isn't the command line rossrv md5 package/service_type?

gvdhoorn gravatar image gvdhoorn  ( 2020-03-31 02:14:15 -0500 )edit

Hi, rossrv md5 <service_type> also works if the service_type is identity :).

Ros_junior gravatar image Ros_junior  ( 2020-03-31 05:04:02 -0500 )edit

Well, I cannot reproduce this. The md5-sum gets calculated even when making a change to a srv, compiling, reverting, and compiling again. So the same content in the same package creates the same md5sum. Are you sure you haven't changed anything else? Can you share the srv files that cause the problem, or better yet, the full package, as well as the packages where you have problems with?

mgruhler gravatar image mgruhler  ( 2020-03-31 07:34:55 -0500 )edit

What the OP describes could happen if perception.srv actually includes another message, and changes are made to the included message. It would appear the hash of perception.srv changes "without changing perception.srv itself". But that would expected.

I don't read that in the question text though.

gvdhoorn gravatar image gvdhoorn  ( 2020-03-31 07:43:07 -0500 )edit

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answered 2020-04-06 22:51:24 -0500

Ros_junior gravatar image

Thank you all for your interest in my question. I got a hint from you.
So, arranging all advises, if scripts .srv are changed, its md5sum will be changed even it is in the same package directory. I checked this result and put the same .srv file into the opposite devices, rosjava workspace, so as to fix this issue.

Whenever md5sum issue occurred, firstly, I should be sure if I make both workspaces have the same ros message package. I thought it was no problem to change the script if it is in the same package directory. But, was wrong.

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Asked: 2020-03-31 01:54:23 -0500

Seen: 89 times

Last updated: Apr 06 '20