## The problem
In a typical debugger, `repr()` is used to display variables and not `str()`.
Several classes in Dynamo have a `__str__()` method that returns useful information and a `__repr__()` that does not. Having to call `str(x)` or `[str(i) for i in x]` in the debugger all the time is a chore.
`str()` should be ["informal, nicely printable"](https://docs.python.org/3/library/stdtypes.html#str) and `repr()` should ["attempt to return a string that would yield an object with the same value when passed to eval()](https://docs.python.org/3/library/functions.html#repr)".
## The solution
In the Python object model, if there is no `__str__` method, `__repr__` is used instead (but not the other way around).
So renaming `__str__` to `__repr__` in a few cases where no `__repr__` method exists now should not change observable behavior, and should make debugging easier.
The specific classes changed were all in `torch._dynamo.variables`:
* `builtin.BuiltinVariable`
* `constant.ConstantVariable`
* `constant.EnumVariable`
* `functions.UserMethodVariable`
* `lazy.LazyVariableTracker`
* `lazy.LazySymNodeFormatString`
* `misc.GetAttrVariable`
* `misc.NullVariable`
* `user_defined.UserDefinedObjectVariable`
Pull Request resolved: https://github.com/pytorch/pytorch/pull/136316
Approved by: https://github.com/XuehaiPan, https://github.com/jansel
## `VariableTracker::build()` hides the Builders
### The problem
In the current code, creating a `VariableTracker` involves choosing one of two `Builder` classes and either calling a method, or calling a constructor that creates an object that you immediately call, [like this](083c9149b7/torch/_dynamo/variables/functions.py (L761-L768)).
Variations on this code are repeated in many places.
More, the `Builder` classes have a lot of dependencies, so they have to be loaded late in the whole import process to avoid circular imports, so they end up being repeatedly imported at local scope.
### The solution
In this commit, the import from `builder` and the logic of choosing and calling the Builder class are hidden in a single static factory method, `VariableTracker.build()`, easier to reason about and to import.
This commit net lowers the total lines of code by over 150 lines by removing repetitive logic and unnecessary local imports.
**CHANGES:** Originally the name of the static method was `VariableTracker.create()` but a static method on a derived class, `LazyVariableTracker.create()` now exists with a different signature that's irreconcilable, so the new static method was renamed to `VariableTracker.build()`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/135714
Approved by: https://github.com/jansel
Fixes https://github.com/pytorch/pytorch/issues/103602.
This PR implements the idea of "if someone creates a string and then ends up not using it, we would prefer to NOT have specialized." mentioned in above issue. Specifically, we create a lazy variable tracker instead of ConstantVariable when we're in FORMAT_VALUE, and when the lazy variable tracker is realized (i.e. it's going to be used), we create a ConstantVariable and the specialization/guarding happens at the time of realization.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/131529
Approved by: https://github.com/ezyang
Fix https://github.com/pytorch/pytorch/issues/124900.
When we reconstruct `ContextWrappingVariables`s, we only reconstruct the context class, not the object. Normally, contexts are active (via `with ctx:`) and we initialize the context object in the resume function. But for the case of inactive contexts (contexts declared ahead of time before the `with` block), we do not reconstruct them properly in the optimized bytecode or resume function. So this PR adds initialization for inactive contexts in the resume function.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/125203
Approved by: https://github.com/jansel
The original motivation for MYPYINDUCTOR was a faster type checking configuration that only checked a subset of files. With the removal of `follow_imports = ignore`, we are now able to use dmypy to do fast incremental typechecking, eliminating the need for this.
Perhaps erroneously, when I tee'ed up this PR I elected to delete the `follow_imports = skip` designations in the mypy-inductor.ini. This lead to a number of extra type error suppressions that I manually edited. You will need to review.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/118432
Approved by: https://github.com/Skylion007
ghstack dependencies: #118414, #118418
