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// Copyright 2018 The Bazel Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.devtools.build.lib.starlarkbuildapi;
import com.google.devtools.build.docgen.annot.DocumentMethods;
import com.google.devtools.build.docgen.annot.StarlarkConstructor;
import com.google.devtools.build.lib.cmdline.Label;
import com.google.devtools.build.lib.packages.semantics.BuildLanguageOptions;
import com.google.devtools.build.lib.starlarkbuildapi.StarlarkConfigApi.BuildSettingApi;
import net.starlark.java.annot.Param;
import net.starlark.java.annot.ParamType;
import net.starlark.java.annot.StarlarkMethod;
import net.starlark.java.eval.Dict;
import net.starlark.java.eval.EvalException;
import net.starlark.java.eval.NoneType;
import net.starlark.java.eval.Sequence;
import net.starlark.java.eval.StarlarkCallable;
import net.starlark.java.eval.StarlarkFunction;
import net.starlark.java.eval.StarlarkThread;
/**
* Interface for a global Starlark library containing rule-related helper and registration
* functions.
*/
@DocumentMethods
public interface StarlarkRuleFunctionsApi<FileApiT extends FileApi> {
String EXEC_COMPATIBLE_WITH_PARAM = "exec_compatible_with";
String TOOLCHAINS_PARAM = "toolchains";
String PROVIDES_DOC =
"A list of providers that the implementation function must return."
+ ""
+ "<p>It is an error if the implementation function omits any of the types of providers "
+ "listed here from its return value. However, the implementation function may return "
+ "additional providers not listed here."
+ ""
+ "<p>Each element of the list is an <code>*Info</code> object returned by "
+ "<a href='globals.html#provider'><code>provider()</code></a>, except that a legacy "
+ "provider is represented by its string name instead.";
@StarlarkMethod(
name = "provider",
doc =
"Defines a provider symbol. The provider may be instantiated by calling it, or used"
+ " directly as a key for retrieving an instance of that provider from a target."
+ " Example:<br><pre class=\"language-python\">" //
+ "MyInfo = provider()\n"
+ "...\n"
+ "def _my_library_impl(ctx):\n"
+ " ...\n"
+ " my_info = MyInfo(x = 2, y = 3)\n"
+ " # my_info.x == 2\n"
+ " # my_info.y == 3\n"
+ " ..." //
+ "</pre><p>See <a href='https://bazel.build/rules/rules#providers'>Rules"
+ " (Providers)</a> for a comprehensive guide on how to use providers." //
+ "<p>Returns a <a href='Provider.html#Provider'><code>Provider</code></a> callable "
+ "value if <code>init</code> is not specified." //
+ "<p>If <code>init</code> is specified, returns a tuple of 2 elements: a <a"
+ " href='Provider.html#Provider'><code>Provider</code></a> callable value and a"
+ " <em>raw constructor</em> callable value. See <a"
+ " href='https://bazel.build/rules/rules#custom_initialization_of_providers'>Rules"
+ " (Custom initialization of custom providers)</a> and the discussion of the"
+ " <code>init</code> parameter below for details.",
parameters = {
@Param(
name = "doc",
named = true,
defaultValue = "''",
doc =
"A description of the provider that can be extracted by documentation generating"
+ " tools."),
@Param(
name = "fields",
doc =
"If specified, restricts the set of allowed fields. <br>Possible values are:<ul> "
+ " <li> list of fields:<br> <pre"
+ " class=\"language-python\">provider(fields = ['a', 'b'])</pre><p> <li>"
+ " dictionary field name -> documentation:<br> <pre"
+ " class=\"language-python\">provider(\n"
+ " fields = { 'a' : 'Documentation for a', 'b' : 'Documentation for b'"
+ " })</pre></ul>All fields are optional.",
allowedTypes = {
@ParamType(type = Sequence.class, generic1 = String.class),
@ParamType(type = Dict.class),
@ParamType(type = NoneType.class),
},
named = true,
positional = false,
defaultValue = "None"),
@Param(
name = "init",
doc =
"An optional callback for preprocessing and validating the provider's field values"
+ " during instantiation. If <code>init</code> is specified,"
+ " <code>provider()</code> returns a tuple of 2 elements: the normal provider"
+ " symbol and a <em>raw constructor</em>." //
+ "<p>A precise description follows; see <a"
+ " href='https://bazel.build/rules/rules#custom_initialization_of_providers'>"
+ "Rules (Custom initialization of providers)</a>"
+ " for an intuitive discussion and use cases." //
+ "<p>Let <code>P</code> be the provider symbol created by calling"
+ " <code>provider()</code>. Conceptually, an instance of <code>P</code> is"
+ " generated by calling a default constructor function <code>c(*args,"
+ " **kwargs)</code>, which does the following:" //
+ "<ul>" //
+ "<li>If <code>args</code> is non-empty, an error occurs.</li>" //
+ "<li>If the <code>fields</code> parameter was specified when"
+ " <code>provider()</code> was called, and if <code>kwargs</code> contains any"
+ " key that was not listed in <code>fields</code>, an error occurs.</li>" //
+ "<li>Otherwise, <code>c</code> returns a new instance that has, for each"
+ " <code>k: v</code> entry in <code>kwargs</code>, a field named"
+ " <code>k</code> with value <code>v</code>." //
+ "</ul>" //
+ "In the case where an <code>init</code> callback is <em>not</em> given, a"
+ " call to the symbol <code>P</code> itself acts as a call to the default"
+ " constructor function <code>c</code>; in other words, <code>P(*args,"
+ " **kwargs)</code> returns <code>c(*args, **kwargs)</code>. For example," //
+ "<pre class=\"language-python\">" //
+ "MyInfo = provider()\n" //
+ "m = MyInfo(foo = 1)" //
+ "</pre>" //
+ "will straightforwardly make it so that <code>m</code> is a"
+ " <code>MyInfo</code> instance with <code>m.foo == 1</code>." //
+ "<p>But in the case where <code>init</code> is specified, the call"
+ " <code>P(*args, **kwargs)</code> will perform the following steps"
+ " instead:" //
+ "<ol>" //
+ "<li>The callback is invoked as <code>init(*args, **kwargs)</code>, that is,"
+ " with the exact same positional and keyword arguments as were passed to"
+ " <code>P</code>.</li>" //
+ "<li>The return value of <code>init</code> is expected to be a dictionary,"
+ " <code>d</code>, whose keys are field name strings. If it is not, an error"
+ " occurs.</li>" //
+ "<li>A new instance of <code>P</code> is generated as if by calling the"
+ " default constructor with <code>d</code>'s entries as keyword arguments, as"
+ " in <code>c(**d)</code>.</li>" //
+ "</ol>" //
+ "<p>NB: the above steps imply that an error occurs if <code>*args</code> or"
+ " <code>**kwargs</code> does not match <code>init</code>'s signature, or the"
+ " evaluation of <code>init</code>'s body fails (perhaps intentionally via a"
+ " call to <a href=\"#fail\"><code>fail()</code></a>), or if the return value"
+ " of <code>init</code> is not a dictionary with the expected schema." //
+ "<p>In this way, the <code>init</code> callback generalizes normal provider"
+ " construction by allowing positional arguments and arbitrary logic for"
+ " preprocessing and validation. It does <em>not</em> enable circumventing the"
+ " list of allowed <code>fields</code>." //
+ "<p>When <code>init</code> is specified, the return value of"
+ " <code>provider()</code> becomes a tuple <code>(P, r)</code>, where"
+ " <code>r</code> is the <em>raw constructor</em>. In fact, the behavior of"
+ " <code>r</code> is exactly that of the default constructor function"
+ " <code>c</code> discussed above. Typically, <code>r</code> is bound to a"
+ " variable whose name is prefixed with an underscore, so that only the"
+ " current .bzl file has direct access to it:" //
+ "<pre class=\"language-python\">" //
+ "MyInfo, _new_myinfo = provider(init = ...)" //
+ "</pre>",
named = true,
allowedTypes = {
@ParamType(type = StarlarkCallable.class),
@ParamType(type = NoneType.class),
},
positional = false,
defaultValue = "None"),
},
useStarlarkThread = true)
Object provider(String doc, Object fields, Object init, StarlarkThread thread)
throws EvalException;
@StarlarkMethod(
name = "rule",
doc =
"Creates a new rule, which can be called from a BUILD file or a macro to create targets."
+ "<p>Rules must be assigned to global variables in a .bzl file; the name of the "
+ "global variable is the rule's name."
+ "<p>Test rules are required to have a name ending in <code>_test</code>, while all "
+ "other rules must not have this suffix. (This restriction applies only to rules, "
+ "not to their targets.)",
parameters = {
@Param(
name = "implementation",
named = true,
doc =
"the Starlark function implementing this rule, must have exactly one parameter: "
+ "<a href=\"ctx.html\">ctx</a>. The function is called during the analysis "
+ "phase for each instance of the rule. It can access the attributes "
+ "provided by the user. It must create actions to generate all the declared "
+ "outputs."),
@Param(
name = "test",
named = true,
defaultValue = "False",
doc =
"Whether this rule is a test rule, that is, whether it may be the subject of a"
+ " <code>blaze test</code> command. All test rules are automatically"
+ " considered <a href='#rule.executable'>executable</a>; it is unnecessary"
+ " (and discouraged) to explicitly set <code>executable = True</code> for a"
+ " test rule. See the <a"
+ " href='https://bazel.build/rules/rules#executable_rules_and_test_rules'>"
+ " Rules page</a> for more information."),
@Param(
name = "attrs",
allowedTypes = {
@ParamType(type = Dict.class),
@ParamType(type = NoneType.class),
},
named = true,
defaultValue = "None",
doc =
"dictionary to declare all the attributes of the rule. It maps from an attribute "
+ "name to an attribute object (see <a href=\"attr.html\">attr</a> module). "
+ "Attributes starting with <code>_</code> are private, and can be used to "
+ "add an implicit dependency on a label. The attribute <code>name</code> is "
+ "implicitly added and must not be specified. Attributes "
+ "<code>visibility</code>, <code>deprecation</code>, <code>tags</code>, "
+ "<code>testonly</code>, and <code>features</code> are implicitly added and "
+ "cannot be overridden. Most rules need only a handful of attributes. To "
+ "limit memory usage, the rule function imposes a cap on the size of attrs."),
// TODO(bazel-team): need to give the types of these builtin attributes
@Param(
name = "outputs",
allowedTypes = {
@ParamType(type = Dict.class),
@ParamType(type = NoneType.class),
@ParamType(type = StarlarkFunction.class) // a function defined in Starlark
},
named = true,
defaultValue = "None",
valueWhenDisabled = "None",
disableWithFlag = BuildLanguageOptions.INCOMPATIBLE_NO_RULE_OUTPUTS_PARAM,
doc =
"This parameter has been deprecated. Migrate rules to use"
+ " <code>OutputGroupInfo</code> or <code>attr.output</code> instead. <p>A"
+ " schema for defining predeclared outputs. Unlike <a"
+ " href='attr.html#output'><code>output</code></a> and <a"
+ " href='attr.html#output_list'><code>output_list</code></a> attributes, the"
+ " user does not specify the labels for these files. See the <a"
+ " href='https://bazel.build/rules/rules#files'>Rules page</a> for more on"
+ " predeclared outputs.<p>The value of this argument is either a dictionary or"
+ " a callback function that produces a dictionary. The callback works similar"
+ " to computed dependency attributes: The function's parameter names are"
+ " matched against the rule's attributes, so for example if you pass"
+ " <code>outputs = _my_func</code> with the definition <code>def"
+ " _my_func(srcs, deps): ...</code>, the function has access to the attributes"
+ " <code>srcs</code> and <code>deps</code>. Whether the dictionary is"
+ " specified directly or via a function, it is interpreted as follows.<p>Each"
+ " entry in the dictionary creates a predeclared output where the key is an"
+ " identifier and the value is a string template that determines the output's"
+ " label. In the rule's implementation function, the identifier becomes the"
+ " field name used to access the output's <a"
+ " href='File.html'><code>File</code></a> in <a"
+ " href='ctx.html#outputs'><code>ctx.outputs</code></a>. The output's label"
+ " has the same package as the rule, and the part after the package is"
+ " produced by substituting each placeholder of the form"
+ " <code>\"%{ATTR}\"</code> with a string formed from the value of the"
+ " attribute <code>ATTR</code>:<ul><li>String-typed attributes are substituted"
+ " verbatim.<li>Label-typed attributes become the part of the label after the"
+ " package, minus the file extension. For example, the label"
+ " <code>\"//pkg:a/b.c\"</code> becomes <code>\"a/b\"</code>.<li>Output-typed"
+ " attributes become the part of the label after the package, including the"
+ " file extension (for the above example, <code>\"a/b.c\"</code>).<li>All"
+ " list-typed attributes (for example, <code>attr.label_list</code>) used in"
+ " placeholders are required to have <i>exactly one element</i>. Their"
+ " conversion is the same as their non-list version"
+ " (<code>attr.label</code>).<li>Other attribute types may not appear in"
+ " placeholders.<li>The special non-attribute placeholders"
+ " <code>%{dirname}</code> and <code>%{basename}</code> expand to those parts"
+ " of the rule's label, excluding its package. For example, in"
+ " <code>\"//pkg:a/b.c\"</code>, the dirname is <code>a</code> and the"
+ " basename is <code>b.c</code>.</ul><p>In practice, the most common"
+ " substitution placeholder is <code>\"%{name}\"</code>. For example, for a"
+ " target named \"foo\", the outputs dict <code>{\"bin\":"
+ " \"%{name}.exe\"}</code> predeclares an output named <code>foo.exe</code>"
+ " that is accessible in the implementation function as"
+ " <code>ctx.outputs.bin</code>."),
@Param(
name = "executable",
named = true,
defaultValue = "False",
doc =
"Whether this rule is considered executable, that is, whether it may be the subject"
+ " of a <code>blaze run</code> command. See the <a"
+ " href='https://bazel.build/rules/rules#executable_rules_and_test_rules'>"
+ " Rules page</a> for more information."),
@Param(
name = "output_to_genfiles",
named = true,
defaultValue = "False",
doc =
"If true, the files will be generated in the genfiles directory instead of the "
+ "bin directory. Unless you need it for compatibility with existing rules "
+ "(e.g. when generating header files for C++), do not set this flag."),
@Param(
name = "fragments",
allowedTypes = {@ParamType(type = Sequence.class, generic1 = String.class)},
named = true,
defaultValue = "[]",
doc =
"List of names of configuration fragments that the rule requires "
+ "in target configuration."),
@Param(
name = "host_fragments",
allowedTypes = {@ParamType(type = Sequence.class, generic1 = String.class)},
named = true,
defaultValue = "[]",
doc =
"List of names of configuration fragments that the rule requires "
+ "in host configuration."),
@Param(
name = "_skylark_testable",
named = true,
defaultValue = "False",
doc =
"<i>(Experimental)</i><br/><br/>"
+ "If true, this rule will expose its actions for inspection by rules that "
+ "depend on it via an <a href=\"globals.html#Actions\">Actions</a> "
+ "provider. The provider is also available to the rule itself by calling "
+ "<a href=\"ctx.html#created_actions\">ctx.created_actions()</a>."
+ "<br/><br/>"
+ "This should only be used for testing the analysis-time behavior of "
+ "Starlark rules. This flag may be removed in the future."),
@Param(
name = TOOLCHAINS_PARAM,
allowedTypes = {@ParamType(type = Sequence.class, generic1 = Object.class)},
named = true,
defaultValue = "[]",
doc =
"If set, the set of toolchains this rule requires. The list can contain String,"
+ " Label, or StarlarkToolchainTypeApi objects, in any combination. Toolchains"
+ " will be found by checking the current platform, and provided to the rule"
+ " implementation via <code>ctx.toolchain</code>."),
@Param(
name = "incompatible_use_toolchain_transition",
defaultValue = "False",
named = true,
doc = "Deprecated, this is no longer in use and should be removed."),
@Param(
name = "doc",
named = true,
defaultValue = "''",
doc =
"A description of the rule that can be extracted by documentation generating "
+ "tools."),
@Param(
name = "provides",
named = true,
positional = false,
defaultValue = "[]",
doc = PROVIDES_DOC),
@Param(
name = EXEC_COMPATIBLE_WITH_PARAM,
allowedTypes = {@ParamType(type = Sequence.class, generic1 = String.class)},
named = true,
positional = false,
defaultValue = "[]",
doc =
"A list of constraints on the execution platform that apply to all targets of "
+ "this rule type."),
@Param(
name = "analysis_test",
named = true,
positional = false,
defaultValue = "False",
doc =
"If true, then this rule is treated as an analysis test. <p>Note: Analysis test"
+ " rules are primarily defined using infrastructure provided in core Starlark"
+ " libraries. See <a"
+ " href=\"https://bazel.build/rules/testing#testing-rules\">Testing</a> for"
+ " guidance. <p>If a rule is defined as an analysis test rule, it becomes"
+ " allowed to use configuration transitions defined using <a"
+ " href=\"#analysis_test_transition\">analysis_test_transition</a> on its"
+ " attributes, but opts into some restrictions: <ul><li>Targets of this rule"
+ " are limited in the number of transitive dependencies they may have. <li>The"
+ " rule is considered a test rule (as if <code>test=True</code> were set)."
+ " This supersedes the value of <code>test</code></li> <li>The rule"
+ " implementation function may not register actions. Instead, it must register"
+ " a pass/fail result via providing <a"
+ " href='AnalysisTestResultInfo.html'>AnalysisTestResultInfo</a>.</li></ul>"),
@Param(
name = "build_setting",
allowedTypes = {
@ParamType(type = BuildSettingApi.class),
@ParamType(type = NoneType.class),
},
defaultValue = "None",
named = true,
positional = false,
doc =
"If set, describes what kind of "
+ "<a href = '${link config#user-defined-build-settings}'><code>build "
+ "setting</code></a> this rule is. See the "
+ "<a href='config.html'><code>config</code></a> module. If this is "
+ "set, a mandatory attribute named \"build_setting_default\" is automatically "
+ "added to this rule, with a type corresponding to the value passed in here."),
@Param(
name = "cfg",
defaultValue = "None",
named = true,
positional = false,
doc =
"If set, points to the configuration transition the rule will "
+ "apply to its own configuration before analysis."),
@Param(
name = "exec_groups",
allowedTypes = {
@ParamType(type = Dict.class),
@ParamType(type = NoneType.class),
},
named = true,
defaultValue = "None",
positional = false,
doc =
"Dict of execution group name (string) to <a"
+ " href='globals.html#exec_group'><code>exec_group</code>s</a>. If set,"
+ " allows rules to run actions on multiple execution platforms within a"
+ " single target. See <a href='${link exec-groups}'>execution groups"
+ " documentation</a> for more info."),
@Param(
name = "compile_one_filetype",
defaultValue = "None",
allowedTypes = {
@ParamType(type = Sequence.class, generic1 = String.class),
@ParamType(type = NoneType.class),
},
named = true,
positional = false,
doc =
"Used by --compile_one_dependency: if multiple rules consume the specified file, "
+ "should we choose this rule over others."),
@Param(
name = "name",
named = true,
defaultValue = "None",
positional = false,
allowedTypes = {@ParamType(type = String.class), @ParamType(type = NoneType.class)},
disableWithFlag = BuildLanguageOptions.INCOMPATIBLE_REMOVE_RULE_NAME_PARAMETER,
valueWhenDisabled = "None",
doc =
"Deprecated: do not use.<p>The name of this rule, as understood by Bazel and"
+ " reported in contexts such as logging,"
+ " <code>native.existing_rule(...)[kind]</code>, and <code>bazel query</code>."
+ " Usually this is the same as the Starlark identifier that gets bound to this"
+ " rule; for instance a rule called <code>foo_library</code> would typically"
+ " be declared as <code>foo_library = rule(...)</code> and instantiated in a"
+ " BUILD file as <code>foo_library(...)</code>.<p>If this parameter is"
+ " omitted, the rule's name is set to the name of the first Starlark global"
+ " variable to be bound to this rule within its declaring .bzl module. Thus,"
+ " <code>foo_library = rule(...)</code> need not specify this parameter if the"
+ " name is <code>foo_library</code>.<p>Specifying an explicit name for a rule"
+ " does not change where you are allowed to instantiate the rule."),
},
useStarlarkThread = true)
StarlarkCallable rule(
StarlarkFunction implementation,
Boolean test,
Object attrs,
Object implicitOutputs,
Boolean executable,
Boolean outputToGenfiles,
Sequence<?> fragments,
Sequence<?> hostFragments,
Boolean starlarkTestable,
Sequence<?> toolchains,
boolean useToolchainTransition,
String doc,
Sequence<?> providesArg,
Sequence<?> execCompatibleWith,
Object analysisTest,
Object buildSetting,
Object cfg,
Object execGroups,
Object compileOneFiletype,
Object name,
StarlarkThread thread)
throws EvalException;
@StarlarkMethod(
name = "aspect",
doc =
"Creates a new aspect. The result of this function must be stored in a global value."
+ " Please see the <a href=\"https://bazel.build/rules/aspects\">introduction to"
+ " Aspects</a> for more details.",
parameters = {
@Param(
name = "implementation",
named = true,
doc =
"A Starlark function that implements this aspect, with exactly two parameters: "
+ "<a href=\"Target.html\">Target</a> (the target to which the aspect is "
+ "applied) and <a href=\"ctx.html\">ctx</a> (the rule context which the target"
+ "is created from). Attributes of the target are available via the "
+ "<code>ctx.rule</code> field. This function is evaluated during the "
+ "analysis phase for each application of an aspect to a target."),
@Param(
name = "attr_aspects",
allowedTypes = {@ParamType(type = Sequence.class, generic1 = String.class)},
named = true,
defaultValue = "[]",
doc =
"List of attribute names. The aspect propagates along dependencies specified in "
+ " the attributes of a target with these names. Common values here include "
+ "<code>deps</code> and <code>exports</code>. The list can also contain a "
+ "single string <code>\"*\"</code> to propagate along all dependencies of a "
+ "target."),
@Param(
name = "attrs",
allowedTypes = {
@ParamType(type = Dict.class),
@ParamType(type = NoneType.class),
},
named = true,
defaultValue = "None",
doc =
"A dictionary declaring all the attributes of the aspect. It maps from an "
+ "attribute name to an attribute object, like `attr.label` or `attr.string` "
+ "(see <a href=\"attr.html\">attr</a> module). Aspect attributes are "
+ "available to implementation function as fields of <code>ctx</code> "
+ "parameter. "
+ ""
+ "<p>Implicit attributes starting with <code>_</code> must have default "
+ "values, and have type <code>label</code> or <code>label_list</code>. "
+ ""
+ "<p>Explicit attributes must have type <code>string</code>, and must use "
+ "the <code>values</code> restriction. Explicit attributes restrict the "
+ "aspect to only be used with rules that have attributes of the same "
+ "name, type, and valid values according to the restriction."),
@Param(
name = "required_providers",
named = true,
defaultValue = "[]",
doc =
"This attribute allows the aspect to limit its propagation to only the targets "
+ "whose rules advertise its required providers. The value must be a "
+ "list containing either individual providers or lists of providers but not "
+ "both. For example, <code>[[FooInfo], [BarInfo], [BazInfo, QuxInfo]]</code> "
+ "is a valid value while <code>[FooInfo, BarInfo, [BazInfo, QuxInfo]]</code> "
+ "is not valid."
+ ""
+ "<p>An unnested list of providers will automatically be converted to a list "
+ "containing one list of providers. That is, <code>[FooInfo, BarInfo]</code> "
+ "will automatically be converted to <code>[[FooInfo, BarInfo]]</code>."
+ ""
+ "<p>To make some rule (e.g. <code>some_rule</code>) targets visible to an "
+ "aspect, <code>some_rule</code> must advertise all providers from at least "
+ "one of the required providers lists. For example, if the "
+ "<code>required_providers</code> of an aspect are "
+ "<code>[[FooInfo], [BarInfo], [BazInfo, QuxInfo]]</code>, this aspect can "
+ "only see <code>some_rule</code> targets if and only if "
+ "<code>some_rule</code> provides <code>FooInfo</code> *or* "
+ "<code>BarInfo</code> *or* both <code>BazInfo</code> *and* "
+ "<code>QuxInfo</code>."),
@Param(
name = "required_aspect_providers",
named = true,
defaultValue = "[]",
doc =
"This attribute allows this aspect to inspect other aspects. The value must be a "
+ "list containing either individual providers or lists of providers but not "
+ "both. For example, <code>[[FooInfo], [BarInfo], [BazInfo, QuxInfo]]</code> "
+ "is a valid value while <code>[FooInfo, BarInfo, [BazInfo, QuxInfo]]</code> "
+ "is not valid."
+ ""
+ "<p>An unnested list of providers will automatically be converted to a list "
+ "containing one list of providers. That is, "
+ "<code>[FooInfo, BarInfo]</code> will automatically be converted to "
+ "<code>[[FooInfo, BarInfo]]</code>. "
+ ""
+ "<p>To make another aspect (e.g. <code>other_aspect</code>) visible to this "
+ "aspect, <code>other_aspect</code> must provide all providers from at least "
+ "one of the lists. In the example of "
+ "<code>[[FooInfo], [BarInfo], [BazInfo, QuxInfo]]</code>, this aspect can "
+ "only see <code>other_aspect</code> if and only if <code>other_aspect</code> "
+ "provides <code>FooInfo</code> *or* <code>BarInfo</code> *or* both "
+ "<code>BazInfo</code> *and* <code>QuxInfo</code>."),
@Param(name = "provides", named = true, defaultValue = "[]", doc = PROVIDES_DOC),
@Param(
name = "requires",
allowedTypes = {@ParamType(type = Sequence.class, generic1 = StarlarkAspectApi.class)},
named = true,
defaultValue = "[]",
doc = "List of aspects required to be propagated before this aspect."),
@Param(
name = "fragments",
allowedTypes = {@ParamType(type = Sequence.class, generic1 = String.class)},
named = true,
defaultValue = "[]",
doc =
"List of names of configuration fragments that the aspect requires "
+ "in target configuration."),
@Param(
name = "host_fragments",
allowedTypes = {@ParamType(type = Sequence.class, generic1 = String.class)},
named = true,
defaultValue = "[]",
doc =
"List of names of configuration fragments that the aspect requires "
+ "in host configuration."),
@Param(
name = TOOLCHAINS_PARAM,
allowedTypes = {@ParamType(type = Sequence.class, generic1 = Object.class)},
named = true,
defaultValue = "[]",
doc =
"If set, the set of toolchains this rule requires. The list can contain String,"
+ " Label, or StarlarkToolchainTypeApi objects, in any combination. Toolchains"
+ " will be found by checking the current platform, and provided to the rule"
+ " implementation via <code>ctx.toolchain</code>."),
@Param(
name = "incompatible_use_toolchain_transition",
defaultValue = "False",
named = true,
doc = "Deprecated, this is no longer in use and should be removed."),
@Param(
name = "doc",
named = true,
defaultValue = "''",
doc =
"A description of the aspect that can be extracted by documentation generating "
+ "tools."),
@Param(
name = "apply_to_generating_rules",
named = true,
positional = false,
defaultValue = "False",
doc =
"If true, the aspect will, when applied to an output file, instead apply to the "
+ "output file's generating rule. "
+ "<p>For example, suppose an aspect propagates transitively through attribute "
+ "`deps` and it is applied to target `alpha`. Suppose `alpha` has "
+ "`deps = [':beta_output']`, where `beta_output` is a declared output of "
+ "a target `beta`. Suppose `beta` has a target `charlie` as one of its "
+ "`deps`. If `apply_to_generating_rules=True` for the aspect, then the aspect "
+ "will propagate through `alpha`, `beta`, and `charlie`. If False, then the "
+ "aspect will propagate only to `alpha`. </p><p>False by default.</p>"),
@Param(
name = EXEC_COMPATIBLE_WITH_PARAM,
allowedTypes = {@ParamType(type = Sequence.class, generic1 = String.class)},
named = true,
positional = false,
defaultValue = "[]",
doc =
"A list of constraints on the execution platform that apply to all instances of"
+ " this aspect."),
@Param(
name = "exec_groups",
allowedTypes = {
@ParamType(type = Dict.class),
@ParamType(type = NoneType.class),
},
named = true,
defaultValue = "None",
positional = false,
doc =
"Dict of execution group name (string) to <a"
+ " href='globals.html#exec_group'><code>exec_group</code>s</a>. If set,"
+ " allows aspects to run actions on multiple execution platforms within a"
+ " single instance. See <a href='${link exec-groups}'>execution groups"
+ " documentation</a> for more info.")
},
useStarlarkThread = true)
StarlarkAspectApi aspect(
StarlarkFunction implementation,
Sequence<?> attributeAspects,
Object attrs,
Sequence<?> requiredProvidersArg,
Sequence<?> requiredAspectProvidersArg,
Sequence<?> providesArg,
Sequence<?> requiredAspects,
Sequence<?> fragments,
Sequence<?> hostFragments,
Sequence<?> toolchains,
boolean useToolchainTransition,
String doc,
Boolean applyToGeneratingRules,
Sequence<?> execCompatibleWith,
Object execGroups,
StarlarkThread thread)
throws EvalException;
@StarlarkMethod(
name = "Label",
doc =
"Converts a label string into a <code>Label</code> object, in the context of the package"
+ " where the calling <code>.bzl</code> source file lives. If the given value is"
+ " already a <code>Label</code>, it is returned unchanged."
+ "<p>For macros, a related function,"
+ " <code><a"
+ " href='native#package_relative_label'>native.package_relative_label()</a></code>,"
+ " converts the input into a <code>Label</code> in the context of the package"
+ " currently being constructed. Use that function to mimic the string-to-label"
+ " conversion that is automatically done by label-valued rule attributes.",
parameters = {
@Param(
name = "input",
allowedTypes = {@ParamType(type = String.class), @ParamType(type = Label.class)},
doc =
"The input label string or Label object. If a Label object is passed, it's"
+ " returned as is.")
},
useStarlarkThread = true)
@StarlarkConstructor
Label label(Object input, StarlarkThread thread) throws EvalException;
@StarlarkMethod(
name = "exec_group",
doc =
"Creates an <a href='${link exec-groups}'>execution group</a> which can be used to"
+ " create actions for a specific execution platform during rule implementation.",
parameters = {
@Param(
name = TOOLCHAINS_PARAM,
allowedTypes = {@ParamType(type = Sequence.class, generic1 = Object.class)},
named = true,
positional = false,
defaultValue = "[]",
doc =
"The set of toolchains this execution group requires. The list can contain String,"
+ " Label, or StarlarkToolchainTypeApi objects, in any combination."),
@Param(
name = EXEC_COMPATIBLE_WITH_PARAM,
allowedTypes = {@ParamType(type = Sequence.class, generic1 = String.class)},
named = true,
positional = false,
defaultValue = "[]",
doc = "A list of constraints on the execution platform."),
@Param(
name = "copy_from_rule",
defaultValue = "False",
named = true,
positional = false,
doc =
"If set to true, this exec group inherits the toolchains and constraints of the"
+ " rule to which this group is attached. If set to any other string this will"
+ " throw an error.")
},
useStarlarkThread = true)
ExecGroupApi execGroup(
Sequence<?> execCompatibleWith,
Sequence<?> toolchains,
Boolean copyFromRule,
StarlarkThread thread)
throws EvalException;
}