test suite: enotify extension: Add tests for interaction between ":encodeurl" and variable size limits.

lib-sieve: enotify extension: Improve handling of variable size limit for ":encodeurl" variable modifier.

lib-sieve: variables extension: Improve handling of variable size limit for ":quotewildcard" modifier.

lib-sieve: variables extension: Respect UTF-8 character sequence boundaries when truncating variables.

Makes it easier to run with valgrind.

plugins: imap_filter_sieve: Put more effort in reconstructing a valid rcpt address for the envelope.

The sieve_user_email setting provides a fallback for when there is no Delivered-To header.

Although it was documented and implemented in essence, it was not actually
available.

Fixes e.g. FILTER+LOGOUT pipelining crash:
Panic: file imap-sync.c: line 832 (cmd_sync_delayed_real): assertion failed: (client->mailbox != NULL)

Before, the whole address list (header value) was returned as an invalid
address, ignoring any valid addresses it may still have contained.

It adds the ability to manually invoke Sieve filtering in IMAP.

Use the new SIEVE_EXECUTE_FLAG_SKIP_RESPONSES flag to prevent any unforseen
mishaps.

This causes the reject and vacation response actions to be skipped without
error.

Signed-off-by: Phil Carmody <phil@dovecot.fi>

The tests blow through these limits all of the time, which
makes the logs very noisy. These three cases are about 4/5ths
of the test logs. Presumably they're the ones that are also
most often needing expansion in real world use too.

Signed-off-by: Phil Carmody <phil@dovecot.fi>

Signed-off-by: Phil Carmody <phil@dovecot.fi>

It is the initial working directory and that may change during testing, so it is
not a good idea to determine this per test.

The problem mainly arose because the stream buffer position was used to
determine how much was written, while the stream buffer position is potentially
decreased by i_stream_try_alloc().

Panic was:

Panic: file istream.c: line 197 (i_stream_read): assertion failed: ((size_t)ret+old_size == _stream->pos - _stream->skip)

The str_append_n() function is now deprecated. At no occasion, the occurence of
NUL in the data is possible or relevant, so each instance is replaced with
str_append_data() rather than str_append_max().

Always return SIEVE_EXEC_KEEP_FAILED instead.

Always return SIEVE_EXEC_KEEP_FAILED instead.

lib-sieve: vacation extension: Enforce subject header limit in Unicode codepoints rather than bytes.