[eitsupi]

Summary

Follow-up to #1949. The socket session's hover and completion handlers now use the shared inspection parser and resolver instead of eval(parse(text = expr)). The request text is no longer evaluated, so hovering counter in repeat counter <- counter + 1 no longer hangs the R session, and the same applies to completion after repeat x$.

Behavior

• Requests that are a name, a constant, or a chain of $ and @ accesses on a name give the same hover text and completion items as before. This covers data frames, lists, environments, S3 classes with $ and .DollarNames() methods, S4 slots, R6 objects, data.table, a $ b with spaces, and constants such as 1, TRUE, NULL and 0x10.
• Other requests (function calls, assignments, multiple expressions, invalid syntax) give no result. Previously, the first of several expressions was evaluated.
• Errors give no result, as hover did before. Completion previously let errors from listing items, such as a failing .DollarNames() method, reach the dispatcher, which replied with an error and printed a warning in the console. Both handlers now give no result, because hover and completion run without an explicit user action.
• Interrupts are not caught, so the dispatcher still replies that the request was interrupted.

Other changes

• The Interactive test for interrupting a slow inspection used local({ ...; Sys.sleep(30) }) as the hover request, which is now rejected. It now hovers an active binding that sleeps when read.