From ab9732b9af5f8dad4ee9c0be47d7f51b1a90e37d Mon Sep 17 00:00:00 2001
From: Jeremy Nimmer <jeremy.nimmer@tri.global>
Date: Mon, 16 Apr 2018 23:46:11 -0400
Subject: [PATCH] Only run library_lint tests when snopt is enabled

---
 .../multibody_plant/BUILD.bazel               |  5 +--
 tools/lint/library_lint.bzl                   | 36 ++++++++++++++++---
 2 files changed, 35 insertions(+), 6 deletions(-)

diff --git a/multibody/multibody_tree/multibody_plant/BUILD.bazel b/multibody/multibody_tree/multibody_plant/BUILD.bazel
index b27cf5677d22..af68dbd2e042 100644
--- a/multibody/multibody_tree/multibody_plant/BUILD.bazel
+++ b/multibody/multibody_tree/multibody_plant/BUILD.bazel
@@ -16,12 +16,13 @@ package(
 drake_cc_package_library(
     name = "multibody_plant",
     deps = [
-        ":everything",
+        ":coulomb_friction",
+        ":multibody_plant_core",
     ],
 )
 
 drake_cc_library(
-    name = "everything",
+    name = "multibody_plant_core",
     srcs = [
         "multibody_plant.cc",
     ],
diff --git a/tools/lint/library_lint.bzl b/tools/lint/library_lint.bzl
index 5b3d276ceca4..7056c78613af 100644
--- a/tools/lint/library_lint.bzl
+++ b/tools/lint/library_lint.bzl
@@ -95,17 +95,45 @@ def library_lint(
 
     # If there was a package_library rule, ensure its deps are comprehensive.
     if package_library_rule:
+        # If snopt is disabled, we have to use a dummy scope and expression.
+        #
+        # Details: When snopt is enabled, we obtain the @snopt source code via
+        # git.  When snopt is disabled, there is no guarantee that git is still
+        # going to work (e.g., the repository is authenticated).  Normally this
+        # is not a problem.  However, during a `bazel query` or `genquery()`
+        # computation, Bazel still builds a graph where the conditional
+        # dependency on snopt is reified, and so its repository_rule gets run
+        # (and fails).  Thus, we shouldn't do any genquery() operations unless
+        # snopt is enabled.  Instead, we'll scope the genquery to a dummy
+        # label, and nerf the expression to be definitionally empty.
+        #
+        # TODO(jwnimmer-tri) Figure out how make linting work even when snopt
+        # is disabled.
+        dummy = "@bazel_tools//tools/cpp:empty"
+        dummy_expression = "{} except {}".format(dummy, dummy)
         native.genquery(
             name = "library_lint_missing_deps",
-            expression = missing_deps_expression,
-            scope = scope,
+            expression = select({
+                "//tools:with_snopt": missing_deps_expression,
+                "//conditions:default": dummy_expression,
+            }),
+            scope = select({
+                "//tools:with_snopt": scope,
+                "//conditions:default": [dummy],
+            }),
             testonly = 1,
             visibility = ["//visibility:private"],
         )
         native.genquery(
             name = "library_lint_extra_deps",
-            expression = extra_deps_expression,
-            scope = scope,
+            expression = select({
+                "//tools:with_snopt": extra_deps_expression,
+                "//conditions:default": dummy_expression,
+            }),
+            scope = select({
+                "//tools:with_snopt": scope,
+                "//conditions:default": [dummy],
+            }),
             testonly = 1,
             visibility = ["//visibility:private"],
         )