nogo is a tool that analyzes the source code of Go programs. (bazel-c…

…ontrib#1759)

It runs alongside the Go compiler in the Bazel Go rules and rejects
programs that contain disallowed coding patterns.

nogo is a powerful tool for preventing bugs and code anti-patterns
early in the development process.

BUILD.bazel

@@ -1,5 +1,6 @@
 load("@io_bazel_rules_go//go:def.bzl", "go_path", "go_vet_test")
 load("@io_bazel_rules_go//go/private:tools/lines_sorted_test.bzl", "lines_sorted_test")
+load("@io_bazel_rules_go//go/private:rules/nogo.bzl", "nogo")
 load("@io_bazel_rules_go//go/private:rules/info.bzl", "go_info")
 load("@io_bazel_rules_go//go/private:context.bzl", "go_context_data")
 load("@io_bazel_rules_go//go/private:rules/stdlib.bzl", "stdlib")
@@ -15,6 +16,11 @@ builders(
     visibility = ["//visibility:public"],
 )
 
+nogo(
+    name = "default_nogo",
+    visibility = ["//visibility:public"],
+)
+
 go_context_data(
     name = "go_context_data",
     strip = select({
@@ -52,6 +58,7 @@ go_path(
         "//go/tools/builders:cgo",
         "//go/tools/builders:compile",
         "//go/tools/builders:embed",
+        "//go/tools/builders:generate_nogo_main",
         "//go/tools/builders:generate_test_main",
         "//go/tools/builders:link",
         "//go/tools/builders:md5sum",

README.rst

@@ -34,6 +34,7 @@ Go rules for Bazel_
 .. _Deprecation schedule: deprecation.rst
 .. _Avoiding conflicts: proto/core.rst#avoiding-conflicts
 .. _Overriding dependencies: go/workspace.rst#overriding-dependencies
+.. _nogo: go/nogo.rst
 
 .. ;; And now we continue with the actual content
 
@@ -76,7 +77,7 @@ Documentation
 ~~~~~~~~~~~~~
 
 * `Core API <go/core.rst>`_
-  
+
   * `go_binary`_
   * `go_library`_
   * `go_test`_
@@ -89,6 +90,7 @@ Documentation
 
 * `Toolchains <go/toolchains.rst>`_
 * `Extra rules <go/extras.rst>`_
+* `nogo build-time code analysis <go/nogo.rst>`_
 * `Build modes <go/modes.rst>`_
 
 Quick links
@@ -109,6 +111,7 @@ The rules are in the alpha stage of development. They support:
 * cgo
 * cross compilation
 * auto generating BUILD files via gazelle_
+* build-time code analysis via nogo_
 * `protocol buffers`_
 
 They currently do not support (in order of importance):
@@ -397,7 +400,7 @@ work in some cases.
 
 In some cases, you may want to set the ``goos`` and ``goarch`` attributes of
 ``go_binary``. This will cross-compile a binary for a specific platform.
-This is necessary when you need to produce multiple binaries for different 
+This is necessary when you need to produce multiple binaries for different
 platforms in a single build. However, note that ``select`` expressions will
 not work correctly when using these attributes.
 
@@ -526,7 +529,7 @@ must be named ``go_sdk``, and it must come *before* the call to
 
   go_register_toolchains()
 
-  
+
 How do I get information about the Go SDK used by rules_go?
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

go/core.rst

@@ -23,6 +23,7 @@ Core go rules
 .. _build constraints: https://golang.org/pkg/go/build/#hdr-Build_Constraints
 .. _select: https://docs.bazel.build/versions/master/be/functions.html#select
 .. _config_setting: https://docs.bazel.build/versions/master/be/general.html#config_setting
+.. _nogo: nogo.rst#nogo
 
 .. role:: param(kbd)
 .. role:: type(emphasis)
@@ -272,6 +273,75 @@ Example
       visibility = ["//visibility:public"],
   )
 
+go_tool_library
+~~~~~~~~~~~~~~~
+
+This builds a Go library from a set of source files that are all part of
+the same package.
+
+This rule is a limited variant of ``go_library`` which may be used to
+bootstrap tools used by rules_go. This avoids a circular dependency.
+If you are building analyzers to be linked into a `nogo`_ binary, you'll
+need to use ``go_tool_library`` since ``go_library`` depends on `nogo`_
+implicitly.
+
+Providers
+^^^^^^^^^
+
+* GoLibrary_
+* GoSource_
+* GoArchive_
+
+Attributes
+^^^^^^^^^^
+
++----------------------------+-----------------------------+---------------------------------------+
+| **Name**                   | **Type**                    | **Default value**                     |
++----------------------------+-----------------------------+---------------------------------------+
+| :param:`name`              | :type:`string`              | |mandatory|                           |
++----------------------------+-----------------------------+---------------------------------------+
+| A unique name for this rule.                                                                     |
++----------------------------+-----------------------------+---------------------------------------+
+| :param:`srcs`              | :type:`label_list`          | :value:`None`                         |
++----------------------------+-----------------------------+---------------------------------------+
+| The list of Go source files that are compiled to create the package.                             |
+| Only :value:`.go` files are permitted. Cgo, assembly, and build constraints                      |
+| are not supported.                                                                               |
++----------------------------+-----------------------------+---------------------------------------+
+| :param:`deps`              | :type:`label_list`          | :value:`None`                         |
++----------------------------+-----------------------------+---------------------------------------+
+| List of Go libraries this library imports directly.                                              |
+| These must be ``go_tool_library`` targets to avoid circular dependencies.                        |
++----------------------------+-----------------------------+---------------------------------------+
+| :param:`embed`             | :type:`label_list`          | :value:`None`                         |
++----------------------------+-----------------------------+---------------------------------------+
+| List of Go libraries this library embeds. Embedded sources will be compiled                      |
+| together with this library's sources, and the combined list of dependencies                      |
+| will be available for import. These libraries must be ``go_tool_library``                        |
+| targets to avoid circular dependencies. See Embedding_ for more information                      |
+| about how and when to use this.                                                                  |
++----------------------------+-----------------------------+---------------------------------------+
+| :param:`data`              | :type:`label_list`          | :value:`None`                         |
++----------------------------+-----------------------------+---------------------------------------+
+| The list of files needed by this rule at runtime. Targets named in the data attribute will       |
+| appear in the *.runfiles area of this rule, if it has one. This may include data files needed    |
+| by the binary, or other programs needed by it. See `data dependencies`_ for more information     |
+| about how to depend on and use data files.                                                       |
++----------------------------+-----------------------------+---------------------------------------+
+
+Example
+^^^^^^^
+
+.. code:: bzl
+
+    go_tool_library(
+        name = "importunsafe",
+        srcs = ["importunsafe.go"],
+        importpath = "importunsafe",
+        deps = ["@org_golang_x_tools//go/analysis:go_tool_library"],
+        visibility = ["//visibility:public"],
+    )
+
 go_binary
 ~~~~~~~~~
 

go/def.bzl

@@ -27,9 +27,12 @@ load(
 )
 load(
     "@io_bazel_rules_go//go/private:repositories.bzl",
-    "go_register_toolchains",
     "go_rules_dependencies",
 )
+load(
+    "@io_bazel_rules_go//go/toolchain:toolchains.bzl",
+    "go_register_toolchains",
+)
 load(
     "@io_bazel_rules_go//go/private:sdk.bzl",
     "go_download_sdk",
@@ -71,6 +74,14 @@ load(
     "@io_bazel_rules_go//go/private:rules/rule.bzl",
     _go_rule = "go_rule",
 )
+load(
+    "@io_bazel_rules_go//go/private:rules/library.bzl",
+    "go_tool_library",
+)
+load(
+    "@io_bazel_rules_go//go/private:rules/nogo.bzl",
+    "nogo",
+)
 
 # Current version or next version to be tagged. Gazelle and other tools may
 # check this to determine compatibility.