godefererr - Analyser that reports incorrectly returned errors from defer closures

Age	Commit message (Collapse)	Author
2023-05-23	Add tests with multiple return values	Teddy Wing
	Don't pass yet as we currently only suggest `(errorVar error)` as the return signature.
2023-05-22	Clean up `checkErrorAssignedInDefer()` function	Teddy Wing
	* Remove debug prints. * Reorganise the code so that similar things are together. * Add comments describing the logic.
2023-05-21	Report function signature declaration using variable name other than err	Teddy Wing
	I had previously hard-coded the variable name "err" as the recommended name declaration in the function signature for simplicity. Now, use the name assigned in the `defer` instead, which is more correct.
2023-05-21	Add 'godefererr' executable	Teddy Wing
	Based on the code from 'gocapturedrefrace'.
2023-05-21	Check whether `return` uses error variable set in `defer`	Teddy Wing
	This reports diagnostics when using `return nil` instead of `return err` when `err` is an error variable assigned in the first `defer` closure.
2023-05-21	Clarify name of `returnsOtherVariable` test	Teddy Wing

2023-05-21	Check whether returned name matches defer error name	Teddy Wing
	Ensure the name of the returned error variable matches the name of the error variable assigned in the `defer` statement.
2023-05-21	Inspect return value looking at type and name	Teddy Wing
	Want to check that the `return` statement uses the same variable used in the `defer` closure. Start inspecting the values to figure out how we can narrow that down. Add a test case for a "good" assignment of a returned error in `defer`.
2023-05-21	Get type information from `return` statement values	Teddy Wing

2023-05-21	Explore inspecting `return` statements for error values	Teddy Wing

2023-05-21	Add skeleton for checking `return` statements after `defer` closures	Teddy Wing

2023-05-21	Correctly `setFirstErrorDeferEndPos` for `doesDeclareErrInSignature`	Teddy Wing
	Since `ident.Obj.Decl` is a `ast.ValueSpec` in `shouldDeclareErrInSignature` but a `ast.Field` in `doesDeclareErrInSignature`, we need to handle both declaration types. Turn the value into an `ast.Node`, which covers both, and use that to determine whether the variable is declared in the closure.
2023-05-21	Working out why doesDeclareErrInSignature doesn't get far in assign loop	Teddy Wing
	We were looking for a `ast.ValueSpec`, but it looks like when `err` is declared in the function signature, the type is `ast.Field`.
2023-05-21	Print the current function for easier debugging	Teddy Wing
	Show me which function the debug print statements belong to.
2023-05-21	Try to store the end position of the first defer closure with error	Teddy Wing
	The idea is to store the end position of the first defer closure that assigns an error variable from the outer scope. Then, we can check the `return` statements in the rest of the function after that position to ensure they use the error variable.
2023-05-21	Update `firstDeferEndPos` name	Teddy Wing
	Clarify intended contents.
2023-05-21	Add ideas for checking `return`s	Teddy Wing

2023-05-21	Idea for checking `return`s	Teddy Wing

2023-05-21	Next step to check usage of error variable in return	Teddy Wing

2023-05-21	Move error variable GenDecl check to function	Teddy Wing
	Give the check a name.
2023-05-21	Ignore errors declared using GenDecl inside defer closure	Teddy Wing
	We don't want to report error variables that were declared inside the closure, as those don't depend on the outside scope.
2023-05-21	Idea to move defer func check to a separate function	Teddy Wing

2023-05-21	Move function `ast.Inspect` to new function	Teddy Wing
	Give it a name.
2023-05-21	Move defer closure `ast.Inspect` to a separate function	Teddy Wing
	Trying to make this easier to read.
2023-05-21	Add test to ensure error vars declared in defer closure are not reported	Teddy Wing

2023-05-20	Report when error declaration in signature is needed	Teddy Wing
	While looking at the assignments in the `defer`, if we encounter an `error`-type assignment, emit a diagnostic if the error named in the lhs of the assignment is not present in the return signature's names. Not sure if this makes sense to me yet. I probably only want to report a problem for a non-declare assignment of an error value when the error type in the return signature is _not_ named at all.
2023-05-20	Get error variable names from type loop	Teddy Wing
	Store the index where we find the `error` type in the function signature's return list so we can use it later to get the corresponding variable names, if any.
2023-05-20	Find function signature return value names	Teddy Wing
	And add a test function that does have named returned values.
2023-05-19	Check for error types in assignments in `defer`	Teddy Wing

2023-05-19	Work out how to get type name of assignments in `defer`	Teddy Wing

2023-05-18	Find assignments in defer closure	Teddy Wing

2023-05-18	Use `FuncDecl` instead of `FuncType`	Teddy Wing
	I didn't read the docs carefully, it turns out `FuncType` only gives us the signature. If we want access to the function body as well to be able to walk its AST, we need a `FuncDecl`.
2023-05-18	Ideas for walking functions first instead of `defer`s first	Teddy Wing
	I was having a hard time figuring out how to get the function where a `defer` occurs from the defer, so I decided to look at all functions first instead, and find out if they contain `defer`s.
2023-05-18	Ideas for an analyser for returning errors from defer	Teddy Wing
	Still working out how to traverse the AST to be able to see the objects I need.
2023-05-16	Add Idea.txt	Teddy Wing
	Idea for a new linter for ensuring errors are returned from `defer` closures.