Implement -hide-all-plugin-packages and -plugin-package(-id), fixing #11244

Summary:
The basic idea is that we have a new set of "exposed modules"
which are /only/ used for plugins, i.e. -fplugin Foo and
--frontend Foo.  You can interact with this namespace
using the flags -plugin-package-id and -plugin-package.
By default, this namespace contains all modules in the
user namespace (as before), but you can toggle that using
-hide-all-plugin-packages.

There is one nasty hack: GhcMake respects -fplugin in
GHC_OPTIONS to make local plugins work correctly.  It also
bails out of you have an import of a module which doesn't
exist locally or in the package database.  The upshot is
that we need to be sure to check in the plugin modules
too, so we don't give a spurious failure when a plugin
is in the plugin namespace but not the main namespace.
A better way to fix this would be to distinguish between
plugin and normal dependencies in ModSummary.

I cheated a little and tweaked a few existing plugins
tests to exercise the new code paths.

TODO: Documentation

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: bgamari, austin, simonpj, duncan

Subscribers: thomie

Differential Revision: https://phabricator.haskell.org/D1661

GHC Trac Issues: #11244

1 files changed, 13 insertions, 3 deletions

diff --git a/testsuite/tests/plugins/Makefile b/testsuite/tests/plugins/Makefile
index c12c33c9c7..28d3ae8aa7 100644
--- a/testsuite/tests/plugins/Makefile
+++ b/testsuite/tests/plugins/Makefile
@@ -2,19 +2,24 @@ TOP=../..
 include $(TOP)/mk/boilerplate.mk
 include $(TOP)/mk/test.mk
 
+# Each of the tests also exercise the various ways to bring plugins into scope
+
+# -hide-all-plugin-packages + -plugin-package
 .PHONY: plugins01
 plugins01:
-	"$(TEST_HC)" $(TEST_HC_OPTS) $(ghcPluginWayFlags) --make -v0 plugins01.hs -package-db simple-plugin/pkg.plugins01/local.package.conf -fplugin Simple.Plugin -fplugin-opt Simple.Plugin:Irrelevant_Option -package simple-plugin
+	"$(TEST_HC)" $(TEST_HC_OPTS) $(ghcPluginWayFlags) --make -v0 plugins01.hs -package-db simple-plugin/pkg.plugins01/local.package.conf -fplugin Simple.Plugin -fplugin-opt Simple.Plugin:Irrelevant_Option -hide-all-plugin-packages -plugin-package simple-plugin
 	./plugins01
 
+# -hide-all-packages + -plugin-package
 .PHONY: plugins07
 plugins07:
-	"$(TEST_HC)" $(TEST_HC_OPTS) $(ghcPluginWayFlags) --make -v0 -O plugins07.hs -package-db rule-defining-plugin/pkg.plugins07/local.package.conf -package rule-defining-plugin -fplugin=RuleDefiningPlugin
+	"$(TEST_HC)" $(TEST_HC_OPTS) $(ghcPluginWayFlags) --make -v0 -O plugins07.hs -package-db rule-defining-plugin/pkg.plugins07/local.package.conf -hide-all-packages -package base -plugin-package rule-defining-plugin -fplugin=RuleDefiningPlugin
 	./plugins07
 
+# -package (should work for backwards compatibility)
 .PHONY: T10420
 T10420:
-	"$(TEST_HC)" $(TEST_HC_OPTS) $(ghcPluginWayFlags) --make -v0 -O T10420.hs -package-db rule-defining-plugin/pkg.T10420/local.package.conf -package rule-defining-plugin
+	"$(TEST_HC)" $(TEST_HC_OPTS) $(ghcPluginWayFlags) --make -v0 -O T10420.hs -package-db rule-defining-plugin/pkg.T10420/local.package.conf -hide-all-packages -package base -package rule-defining-plugin
 	./T10420
 
 .PHONY: T10294
@@ -31,3 +36,8 @@ frontend01:
 	"$(TEST_HC)" $(TEST_HC_OPTS) $(ghcPluginWayFlags) -Wall -package ghc -c FrontendPlugin.hs
 	"$(TEST_HC)" $(TEST_HC_OPTS) $(ghcPluginWayFlags) --frontend FrontendPlugin -ffrontend-opt foobar frontend01
 	./frontend01
+
+# -hide-all-plugin-packages + -package (this should not work!)
+.PHONY: T11244
+T11244:
+	! "$(TEST_HC)" $(TEST_HC_OPTS) $(ghcPluginWayFlags) --make -v0 -O T11244.hs -package-db rule-defining-plugin/pkg.T11244/local.package.conf -hide-all-plugin-packages -package rule-defining-plugin -fplugin=RuleDefiningPlugin