[web] Return useful error messages when exceptions arise in ajax controllers (closes #3932503) The call to super() in RemoteCallException passes 'reason' all the way to python's Exception.__init__() which is then stored in Exception.args. This way, CubicWebPublisher.ajax_error_handler() gets a useful error message when calling unicode(exc). The change to uilib is just to prepend the exception type name. Just a small improvement.

[test] Fix test breakage uncovered by previous changeset Now that Binary.__eq__ doesn't always return true, this test started failing. CWAttribute.defaultval is zpickled, and the description_format attribute is a String, meaning unicode, so adjust the expected test result.

[etwist] use more specific REQUEST_ENTITY_TOO_LARGE instead of BAD_REQUEST When a request body exceeds the configured limit, return 413 to the client instead of a generic 400.

[entities, view] delete dead code The auto_unwrap_bw_compat metaclass calls unwrap_adapter_compat, which was removed in changeset 697a8181ba30 "remove 3.9 bw compat". So this can't possibly work anymore, meaning we can get rid of it.

[book] stop talking about the hg `forest` extension

[book] update sections about dependencies This is probably incomplete, but it's a start.

[web/component] move unicode() call around Makes Aurélien happier.

[web/js] replace callAddOrDeleteThenReload with more generic callAjaxFuncThenReload That's going to be a more useful replacement for callUserCallbackThenReload. Closes #4178566.

[hooks/syncsession] try to remove cnx vs session confusion

Fix Binary.__eq__ (closes #4172701) Due to a typo we always returned true, which was unhelpful.

[dataimport] stop ignoring errors on flush That can only result in database corruption.

[dataimport] don't commit on flush Changeset 26cdfc6dd6f8 introduced this confusion for no apparent reason, and it doesn't make much sense.