> Is it considered contract violation because the IP was publicly visible?
Not because of that, no. It's a contract violation because there is a contract of sorts (the license agreement). If the code was obtained through hacking, breaking and entering, etc., then we would be talking about theft.
> Or because there was a license that could be used without signing?
It is not necessary to sign something in order to enter into a contractual relationship. There is some gray area in terms of whether or not specific sorts of licensing is legally effective (click-wrap agreements, etc.), but the principle holds generally.
A license is type of contract. If you are using something under the terms of a license, violating the terms of that license is a kind of contract violation.
> If neither of those were true (let's say it was company secret source code, which was never licensed, but a copy was obtained and used anyway), would it still be a contract violation?
No, there is no license there. It's hard to say what, if any, violation there is in that case without knowing the specifics of the case. It could be a copyright violation. If the code was actually stolen, then it could be theft or receiving stolen property. Or it could simply not be a violation.
IANAL, by the way. I'm just relating my understanding of things. I could be wrong.
Not because of that, no. It's a contract violation because there is a contract of sorts (the license agreement). If the code was obtained through hacking, breaking and entering, etc., then we would be talking about theft.
> Or because there was a license that could be used without signing?
It is not necessary to sign something in order to enter into a contractual relationship. There is some gray area in terms of whether or not specific sorts of licensing is legally effective (click-wrap agreements, etc.), but the principle holds generally.
A license is type of contract. If you are using something under the terms of a license, violating the terms of that license is a kind of contract violation.
> If neither of those were true (let's say it was company secret source code, which was never licensed, but a copy was obtained and used anyway), would it still be a contract violation?
No, there is no license there. It's hard to say what, if any, violation there is in that case without knowing the specifics of the case. It could be a copyright violation. If the code was actually stolen, then it could be theft or receiving stolen property. Or it could simply not be a violation.
IANAL, by the way. I'm just relating my understanding of things. I could be wrong.