Previous interface of ngx_open_dir() assumed that passed directory name has a room for NGX_DIR_MASK at the end (NGX_DIR_MASK_LEN bytes). While all direct users of ngx_dir_open() followed this interface, this also implied similar requirements for indirect uses - in particular, via ngx_walk_tree(). Currently none of ngx_walk_tree() uses provides appropriate space, and fixing this does not look like a right way to go. Instead, ngx_dir_open() interface was changed to not require any additional space and use appropriate allocations instead.
Previously, AF_UNIX addresses misbehaved as AF_INET, which typically resulted in $uid_set composed from the middle of sun_path.
If SSL_write_early_data() returned SSL_ERROR_WANT_WRITE, stop further reading using a newly introduced c->ssl->write_blocked flag, as otherwise this would result in SSL error "ssl3_write_bytes:bad length". Eventually, normal reading will be restored by read event posted from successful SSL_write_early_data(). While here, place "SSL_write_early_data: want write" debug on the path.
Previously, AF_UNIX client addresses were handled as AF_INET, leading to unexpected results.
Previously, if an SRV record was successfully resolved, but all of its A records failed to resolve, NXDOMAIN was returned to the caller, which is considered a successful resolve rather than an error. This could result in losing the result of a previous successful resolve by the caller. Now NXDOMAIN is only returned if at least one A resolve completed with this code. Otherwise the error state of the first A resolve is returned.
Previously, unnamed regex captures matched in the parent request, were not available in a cloned subrequest. Now 3 fields related to unnamed captures are copied to a cloned subrequest: r->ncaptures, r->captures and r->captures_data. Since r->captures cannot be changed by either request after creating a clone, a new flag r->realloc_captures is introduced to force reallocation of r->captures. The issue was reported as a proxy_cache_background_update misbehavior in http://mailman.nginx.org/pipermail/nginx/2018-December/057251.html.