Prior to this commit, connections from 'sync_db_pools' assumed that they
were being dropped in an async context. This is overwhelmingly the
common case as connections are typically dropped immediately after
request processing. Nothing requires this, however, so holding a
connection beyond the scope of the async context was possible (i.e. by
storing a connection in managed state). Given the connection's `Drop`
impl calls `spawn_blocking`, this resulted in a panic on drop.
This commit resolves the issue by modifying `Drop` so that it calls
`spawn_blocking` only when it is executing inside an async context. If
not, the connection is dropped normally, without `spawn_blocking`.
Generates a new method on attributed types, `pool()`, which returns an
opaque reference to a type that can be used to get pooled connections.
Also adds a code-generated example to the crate docs which includes
real, proper function signatures and fully checked examples.
Resolves#1884.
Closes#1972.
This follows the completed graduation of stable contrib features into
core, removing 'rocket_contrib' in its entirety in favor of two new
crates. These crates are versioned independently of Rocket's core
libraries, allowing upgrades to dependencies without consideration for
versions in core libraries.
'rocket_dyn_templates' replaces the contrib 'templates' features. While
largely a 1-to-1 copy, it makes the following changes:
* the 'tera_templates' feature is now 'tera'
* the 'handlebars_templates' feature is now 'handlebars'
* fails to compile if neither 'tera' nor 'handlebars' is enabled
'rocket_sync_db_pools' replaces the contrib 'database' features. It
makes no changes to the replaced features except that the `database`
attribute is properly documented at the crate root.