Implemented the type tracer for Awkward-Dask. (#1110)

* Starting to implement the type tracer for Awkward-Dask.

* Actually testing it.

* It predicts Forms and Types.

* Convenience methods for making typetracers.

* TypeTracer.instance().

* TypeTracerArray.__getitem__(slice).

* Black.

* Through RecordArray.

* Through BitMaskedArray.

* Added checks throughout 0896.

* Rename test-data.yml to kernel-test-data.yml.

* Instrumented tests from #959.

* Instrumented tests from #1031.

* numpy.broadcast_shapes is too new.

* Through 0011_v2-listarray in the v2 tests.

* Python 2.7 needs Ellipsis to be spelled out.

* Through 0020_v2-support-unsigned-indexes in the v2 tests.

* Through 0023_v2-regular-array in the v2 tests.

* Through all slicing in the v2 tests; next is 0070_v2-argmin-and-argmax.

* Through test_0070_v2-argmin-and-argmax.py in the v2 tests; ak.to_list was wrong, and subsequently the reducer implementation.

* First use of 'fill' (had to split into 'fill_zero', 'fill_other').

* Through 0111_v2-jagged-and-masked-getitem in the v2 tests; added nplike.known_shape.

* Through 0115_v2-generic-reducer-operation in the v2 tests.

* Through 1059_v2-localindex in the v2 tests.

* Added typetracer to all v2 tests (where possible).

* Fixed pre-commit.

* Fixed merge.

dev/generate-tests.py

@@ -185,7 +185,7 @@ def readspec():
         loadfile = yaml.safe_load(specfile)
         indspec = loadfile["kernels"]
         data = yaml.safe_load(
-            open(os.path.join(CURRENT_DIR, "..", "test-data.yml"), "r")
+            open(os.path.join(CURRENT_DIR, "..", "kernel-test-data.yml"), "r")
         )["tests"]
         for spec in indspec:
             if "def " in spec["definition"]:
@@ -704,7 +704,7 @@ class Error(ctypes.Structure):
 
 def genunittests():
     print("Generating Unit Tests")
-    datayml = open(os.path.join(CURRENT_DIR, "..", "test-data.yml"), "r")
+    datayml = open(os.path.join(CURRENT_DIR, "..", "kernel-test-data.yml"), "r")
     data = yaml.safe_load(datayml)["unit-tests"]
     for function in data:
         num = 0

src/awkward/_util.py

@@ -54,9 +54,9 @@ def isint(x):
     Returns True if and only if ``x`` is an integer (including NumPy, not
     including bool).
     """
-    return isinstance(x, (int, numbers.Integral, np.integer)) and not isinstance(
-        x, (bool, np.bool_)
-    )
+    return isinstance(
+        x, (int, numbers.Integral, np.integer, ak._v2._typetracer.Interval)
+    ) and not isinstance(x, (bool, np.bool_))
 
 
 def isnum(x):
@@ -348,6 +348,21 @@ def typestrs(behavior):
     return out
 
 
+def gettypestr(parameters, typestrs):
+    if parameters is not None:
+        record = parameters.get("__record__")
+        if record is not None:
+            typestr = typestrs.get(record)
+            if typestr is not None:
+                return typestr
+        array = parameters.get("__array__")
+        if array is not None:
+            typestr = typestrs.get(array)
+            if typestr is not None:
+                return typestr
+    return None
+
+
 def numba_record_typer(layouttype, behavior):
     behavior = Behavior(ak.behavior, behavior)
     rec = layouttype.parameters.get("__record__")

src/awkward/_v2/__init__.py

@@ -9,3 +9,4 @@
 import awkward._v2.types  # noqa: F401
 import awkward._v2.forms  # noqa: F401
 import awkward._v2._slicing  # noqa: F401
+import awkward._v2._typetracer  # noqa: F401