Reid D McKenzie
37266cdcd9
This commit implements zapp! and rules_zapp, as a proof of concept of lighter-weight easily hacked on self-extracting zipapps. Think Pex or Shiv but with less behavior and more user control. Or at least hackability.
249 lines
7.5 KiB
Python
249 lines
7.5 KiB
Python
"""
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An implementation of driving zappc from Bazel.
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"""
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load("@rules_python//python:defs.bzl", "py_library", "py_binary")
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DEFAULT_COMPILER = "//projects/zapp:zappc"
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DEFAULT_RUNTIME = "//projects/zapp:zapp_support"
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def _store_path(path, ctx, imports):
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"""Given a path, prepend the workspace name as the zappent directory"""
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# It feels like there should be an easier, less fragile way.
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if path.startswith("../"):
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# External workspace, for example
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# '../protobuf/python/google/protobuf/any_pb2.py'
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stored_path = path[len("../"):]
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elif path.startswith("external/"):
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# External workspace, for example
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# 'external/protobuf/python/__init__.py'
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stored_path = path[len("external/"):]
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else:
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# Main workspace, for example 'mypackage/main.py'
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# stored_path = ctx.workspace_name + "/" + path
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stored_path = path
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matching_prefix = None
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for i in imports:
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if stored_path.startswith(i):
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stored_path = stored_path[len(i):]
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matching_prefix = i
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break
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stored_path = stored_path.lstrip("/")
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return stored_path
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def _check_script(point, sources_map):
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"""Check that a given 'script' (eg. module:fn ref.) maps to a file in sources."""
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fname = point.split(":")[0].replace(".", "/") + ".py"
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if fname not in sources_map:
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fail("Point %s (%s) is not a known source!" % (fname, sources_map))
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def _zapp_impl(ctx):
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"""Implementation of zapp() rule"""
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# TODO: Take wheels and generate a .deps/ tree of them, filtering whl/pypi source files from srcs
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whls = []
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for lib in ctx.attr.wheels:
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for f in lib.data_runfiles.files.to_list():
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whls.append(f)
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# TODO: also handle ctx.attr.src.data_runfiles.symlinks
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srcs = [
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f for f in ctx.attr.src.default_runfiles.files.to_list()
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]
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# Find the list of directories to add to sys
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import_roots = [
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r.replace(ctx.workspace_name + "/", "", 1)
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for r in ctx.attr.src[PyInfo].imports.to_list()
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]
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for r0 in import_roots:
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for r1 in import_roots:
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if r0 == r1:
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continue
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elif r0.startswith(r1):
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fail("Import root conflict between %s and %s" % r0, r1)
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# Dealing with main
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main_py_file = ctx.files.main
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main_py_ref = ctx.attr.entry_point
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if main_py_ref and main_py_file:
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fail("Only one of `main` or `entry_point` should be specified")
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elif main_py_ref:
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# Compute a main module
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main_py_file = main_py_ref.split(":")[0].replace(".", "/") + ".py"
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elif main_py_file:
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# Compute a main module reference
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if len(main_py_file) > 1:
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fail("Expected exactly one .py file, found these: %s" % main_py_file)
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main_py_file = main_py_file[0]
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if main_py_file not in ctx.attr.src.data_runfiles.files.to_list():
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fail("Main entry point [%s] not listed in srcs" % main_py_file, "main")
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# Compute the -m <> equivalent for the 'main' module
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main_py_ref = _store_path(main_py_file.path, ctx, import_roots).replace(".py", "").replace("/", ".")
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# Make a manifest of files to store in the .zapp file. The
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# runfiles manifest is not quite right, so we make our own.
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sources_map = {}
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# Now add the regular (source and generated) files
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for input_file in srcs:
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stored_path = _store_path(input_file.short_path, ctx, import_roots)
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if stored_path:
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local_path = input_file.path
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if stored_path in sources_map and sources_map[stored_path] != '':
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fail("File path conflict between %s and %s" % sources_map[stored_path], local_path)
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sources_map[stored_path] = local_path
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_check_script(main_py_ref, sources_map)
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for p in ctx.attr.prelude_points:
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_check_script(p, sources_map)
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if "__main__.py" in sources_map:
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fail("__main__.py conflict:",
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sources_map["__main__.py"],
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"conflicts with required generated __main__.py")
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# Write the list to the manifest file
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manifest_file = ctx.actions.declare_file(ctx.label.name + ".zapp-manifest.json")
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ctx.actions.write(
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output = manifest_file,
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content = json.encode({
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"shebang": ctx.attr.shebang,
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"sources": sources_map,
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"zip_safe": ctx.attr.zip_safe,
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"prelude_points": ctx.attr.prelude_points,
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"entry_point": main_py_ref,
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"wheels": {w.path.split("/")[-1]: {"hashes": [], "source": w.path} for w in whls},
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}),
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is_executable = False,
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)
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# Run compiler
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ctx.actions.run(
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inputs = [
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manifest_file,
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] + srcs + whls,
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tools = [],
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outputs = [ctx.outputs.executable],
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progress_message = "Building zapp file %s" % ctx.label,
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executable = ctx.executable.compiler,
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arguments = [
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"--debug",
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"-o", ctx.outputs.executable.path,
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manifest_file.path
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],
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mnemonic = "PythonCompile",
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use_default_shell_env = True,
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)
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# .zapp file itself has no runfiles and no providers
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return []
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zapp = rule(
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attrs = {
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"src": attr.label(mandatory = True),
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"main": attr.label(allow_single_file = True),
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"wheels": attr.label_list(),
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"entry_point": attr.string(),
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"prelude_points": attr.string_list(),
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"compiler": attr.label(
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default = Label(DEFAULT_COMPILER),
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executable = True,
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cfg = "host",
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),
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"shebang": attr.string(default = "/usr/bin/env python3"),
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"zip_safe": attr.bool(default = True),
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"root_import": attr.bool(default = False),
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},
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executable = True,
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implementation = _zapp_impl,
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)
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def zapp_binary(name,
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main=None,
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entry_point=None,
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prelude_points=[],
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deps=[],
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imports=[],
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test=False,
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compiler=None,
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zip_safe=True,
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**kwargs):
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"""A self-contained, single-file Python program, with a .zapp file extension.
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Args:
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Same as py_binary, but accepts some extra args -
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entry_point:
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The script to run as the main.
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prelude_points:
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Additional scripts (zapp middlware) to run before main.
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compiler:
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Lable identifying the zapp compiler to use. You shouldn't need to change this.
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zip_safe:
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Whether to import Python code and read datafiles directly from the zip
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archive. Otherwise, if False, all files are extracted to a temporary
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directory on disk each time the zapp file executes.
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"""
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srcs = kwargs.pop("srcs", [])
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if main and main not in srcs:
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srcs.append(main)
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whls = []
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src_deps = []
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for d in deps:
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if d.find("//pypi__") != -1:
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whls.append(d + ":whl")
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else:
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src_deps.append(d)
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py_library(
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name = name + ".whls",
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data = whls,
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)
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py_library(
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name = name + ".lib",
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srcs = srcs,
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deps = (src_deps or []) + [DEFAULT_RUNTIME],
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imports = imports,
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**kwargs
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)
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zapp(
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name = name,
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src = name + ".lib",
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compiler = compiler,
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main = main,
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entry_point = entry_point,
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prelude_points = prelude_points,
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zip_safe = zip_safe,
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wheels = [name + ".whls"],
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)
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def zapp_test(name, **kwargs):
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"""Same as zapp_binary, just sets the test=True bit."""
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kwargs.pop("test")
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zapp_binary(name, test=True, **kwargs)
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