(Aside: it doesn’t matter whether B calls A; linking with it is sufficient. In your example, B’s source became GPL licensed because it was linked with a publicly released A)
My logic was incorrect. I assumed that the exact same source code for now GPL licensed B from earlier revision revisions would have to be GPL licensed, too (and because of it, anything linked with that, linked with code linked with that, etc.).
However, licensing (unlike copyright) doesn’t work that way. Copyright owners can even release the exact same set of source code 7nder multiple licenses.
My conclusion still stands, though. Companies are right to worry about using GPL-licensed software.
My logic was incorrect. I assumed that the exact same source code for now GPL licensed B from earlier revision revisions would have to be GPL licensed, too (and because of it, anything linked with that, linked with code linked with that, etc.).
However, licensing (unlike copyright) doesn’t work that way. Copyright owners can even release the exact same set of source code 7nder multiple licenses.
My conclusion still stands, though. Companies are right to worry about using GPL-licensed software.