Re: [Tarantool-patches] [PATCH 1/2] box: allow schema upgrades within a release

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

Thanks for the patch!

On 19/03/2020 10:14, Chris Sosnin wrote:
> To avoid cases when a user has an incorrectly upgraded schema, we
> introduce new versioning, which can be used to perform upgrades
> within a single release.
> 
> Closes #4804
> Needed for #4666
> ---
>  src/box/lua/upgrade.lua | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/src/box/lua/upgrade.lua b/src/box/lua/upgrade.lua
> index 075cc236e..92c3b460e 100644
> --- a/src/box/lua/upgrade.lua
> +++ b/src/box/lua/upgrade.lua
> @@ -27,12 +27,14 @@ local mkversion = {}
>  mkversion.__index = mkversion
>  setmetatable(mkversion, {__call = function(c, ...) return c.new(...) end})
>  
> -function mkversion.new(major, minor, patch)
> +function mkversion.new(major, minor, patch, build)
>      local self = setmetatable({}, mkversion)
>      self.major = major
>      self.minor = minor
>      self.patch = patch
> +    self.build = build or 0
>      self.id = bit.bor(bit.lshift(bit.bor(bit.lshift(major, 8), minor), 8), patch)
> +    self.id = bit.bor(bit.lshift(self.id, 8), self.build)
>      return self
>  end

Since we don't update mkversion.__tostring(), user during upgrade
will see his logs as

    > set schema version to 2.3.1
    > set schema version to 2.3.1
    > set schema version to 2.3.1
    ... depending on how many schema versions we have within
    release.

Perhaps, it is worth adding the build version to __tostring()
method. So as not to confuse the user, and simplify debug so
as user could tell between which builds the upgrade failed.

It does not affect version visibility - box.info.version() is
reported differently.