Reason

For a better understanding of where the error occurred, it is desirable to have some kind of interface where you could get a nested error. A specific example of use can be found here tarantool/crud#186.

It will be inconvenient to catch errors if there is a high level of nesting. For example (vshard -> crud -> cartridge-java -> client-app) each of these api can throw an error, catch it and generate a new one, so it will be difficult to find out what the original error was.

Examples from other languages

The functionality of nested/chained errors is implemented in other languages:

1. Java

catch(IOException e) {
  throw new ApplicationException("Failed on reading file soandso", e);
  //                              ^ Message                        ^ Cause
}
...
// then when we catch error, we can get cause
catch(ApplicationException e) {
  e.getCause()
  ...
}

2. Python 3

try:
    v = {}['a']
except KeyError as e:
    raise ValueError('failed') from e

# then when we catch error, we can get cause
except ValueError as e:
    e.__cause__

Change homepage in rockspec desc.
..and source

Typically stack size may be ~4 kB or more

It's too expensive when you send error message via network

Now we send stack trace twice (https://github.com/tarantool/errors/blob/master/errors.lua#L94)

Let's concatenate "str" and "stack" only on tostring call

1. Set up open-source-based testing
2. Upload rockspec to rocks.tarantool.org
3. Remove redundant makefile spaghetti

Steps to reproduce:

1. Start cartridge, setup everything
2. Call errors.deprecate() on any instance
3. Voila, the instance is dead!

Responce from cartridge-cli:
⨯ Connection was closed. Probably instance process isn't running anymore

In logs:

cartridge.srv-1 | 2022-11-18 14:29:31.884 [89170] main/151/console/unix/: srv_basic.lua:10 E> DeprecationError: abc (builtin/box/console.lua:412)
cartridge.srv-1 | stack traceback:
cartridge.srv-1 |       builtin/box/console.lua:412: in function <builtin/box/console.lua:385>
cartridge.srv-1 |       [string "local function func(...) return require('cons..."]:1: in main chunk
cartridge.srv-1 |       [C]: in function 'pcall'
cartridge.srv-1 |       builtin/box/console.lua:412: in function 'eval'
cartridge.srv-1 |       builtin/box/console.lua:723: in function 'repl'
cartridge.srv-1 |       builtin/box/console.lua:895: in function <builtin/box/console.lua:881>
cartridge.srv-1 |       [C]: in function 'pcall'
cartridge.srv-1 |       builtin/socket.lua:1084: in function <builtin/socket.lua:1082>

Tarantool 2.10.3-0-g8aca8a1
Target: Darwin-x86_64-Release
Build options: cmake . -DCMAKE_INSTALL_PREFIX=/usr/local/Cellar/tarantool/2.10.3 -DENABLE_BACKTRACE=ON
Compiler: /usr/bin/clang /usr/bin/clang++
C_FLAGS: -fexceptions -funwind-tables -fno-common -fopenmp -msse2 -Wformat -Wformat-security -Werror=format-security -fstack-protector-strong -fPIC -std=c11 -Wall -Wextra -Wno-strict-aliasing -Wno-char-subscripts -Wno-format-truncation -Wno-gnu-alignof-expression -Wno-cast-function-type
CXX_FLAGS: -fexceptions -funwind-tables -fno-common -fopenmp -msse2 -Wformat -Wformat-security -Werror=format-security -fstack-protector-strong -fPIC -std=c++11 -Wall -Wextra -Wno-strict-aliasing -Wno-char-subscripts -Wno-format-truncation -Wno-invalid-offsetof -Wno-gnu-alignof-expression -Wno-cast-function-type

Cartridge master

The module uses duck-typing to tell error objects from other tables. I can't see a reason why this function should remain private.

Error classes should be CamelCase