cuDF error handling document (#7917)

This document aims to give instruction the following two things:
- What to throw given invalid user inputs
- How should cuDF handle exceptions from libcudf

Authors:
  - Michael Wang (https://github.com/isVoid)

Approvers:
  - Bradley Dice (https://github.com/bdice)
  - Vyas Ramasubramani (https://github.com/vyasr)

URL: #7917

docs/cudf/source/developer_guide/contributing_guide.md

@@ -108,4 +108,31 @@ Any attempt to write pure Cython code for this purpose should be justified with
 
 ## Exception handling
 
-This section is under development, see https://github.com/rapidsai/cudf/pull/7917.
+In alignment with [maintaining compatibility with pandas](#pandas-compatibility),
+any API that cuDF shares with pandas should throw all the same exceptions as the
+corresponding pandas API given the same inputs.
+However, it is not required to match the corresponding pandas API's exception message.
+
+When writing error messages,
+sufficient information should be included to help users locate the source of the error,
+such as including the expected argument type versus the actual argument provided.
+
+For parameters that are not yet supported,
+raise `NotImplementedError`.
+There is no need to mention when the argument will be supported in the future.
+
+### Handling libcudf Exceptions
+
+Currently libcudf raises `cudf::logic_error` and `cudf::cuda_error`.
+These error types are mapped to `RuntimeError` in python.
+Several APIs use the exception payload `what()` message to determine the exception type raised by libcudf.
+
+Determining error type based on exception payload is brittle since libcudf does not maintain API stability on exception messages.
+This is a compromise due to libcudf only raising a limited number of error types.
+Only adopt this strategy when necessary.
+
+The projected roadmap is to diversify the exception types raised by libcudf.
+Standard C++ natively supports various [exception types](https://en.cppreference.com/w/cpp/error/exception),
+which Cython maps to [these Python exception types](https://docs.cython.org/en/latest/src/userguide/wrapping_CPlusPlus.html#exceptions).
+In the future, libcudf may employ custom C++ exception types.
+If that occurs, this section will be updated to reflect how these may be mapped to desired Python exception types.

docs/cudf/source/developer_guide/index.md

@@ -21,6 +21,7 @@ Additionally, it includes longer sections on more specific topics like testing a
 :maxdepth: 2
 
 library_design
+contributing_guide
 documentation
 benchmarking
 options