Don't rebuild dependencies by default

Unless it's a symbolic link, it's built directly, FULL=1 is set
or the file ebin/dep_built in the dependency is removed.

See the documentation changes for more details.

This provides immense build speed gains, for example on a
RabbitMQ project it went from 10s to 1s for the 2nd+ builds.

1 files changed, 103 insertions, 0 deletions

diff --git a/test/core_deps.mk b/test/core_deps.mk
index 3b44a13..78180f3 100644
--- a/test/core_deps.mk
+++ b/test/core_deps.mk
@@ -106,6 +106,109 @@ core-deps-build-js: build clean
 		false = lists:member(jquery, Deps), \
 		halt()"
 
+core-deps-dep-built: build clean
+
+	$i "Bootstrap a new OTP library named $(APP)"
+	$t mkdir $(APP)/
+	$t cp ../erlang.mk $(APP)/
+	$t $(MAKE) -C $(APP) -f erlang.mk bootstrap-lib $v
+
+	$i "Add cowlib to the list of dependencies"
+	$t perl -ni.bak -e 'print;if ($$.==1) {print "DEPS = cowlib\n"}' $(APP)/Makefile
+
+	$i "Build the application"
+	$t $(MAKE) -C $(APP) $v
+
+	$i "Touch one cowlib file to mark it for recompilation"
+	$t $(SLEEP)
+	$t touch $(APP)/deps/cowlib/src/cow_http.erl
+
+	$i "Check that cowlib is not rebuilt"
+	$t touch $(APP)/EXPECT
+	$t $(SLEEP)
+	$t $(MAKE) -C $(APP) $v
+	$t find $(APP)/deps/cowlib -type f -newer $(APP)/EXPECT | sort | diff $(APP)/EXPECT -
+	$t rm $(APP)/EXPECT
+
+	$i "Delete the dep_built file"
+	$t rm $(APP)/deps/cowlib/ebin/dep_built
+
+	$i "Check that cowlib was rebuilt"
+	$t printf "%s\n" \
+		$(APP)/deps/cowlib/cowlib.d \
+		$(APP)/deps/cowlib/ebin/cowlib.app \
+		$(APP)/deps/cowlib/ebin/cow_http.beam \
+		$(APP)/deps/cowlib/ebin/dep_built | sort > $(APP)/EXPECT
+	$t $(SLEEP)
+	$t $(MAKE) -C $(APP) $v
+# Files in .git might end up modified due to the id generation in the .app file.
+	$t find $(APP)/deps/cowlib -type f -newer $(APP)/EXPECT | grep -v ".git" | sort | diff $(APP)/EXPECT -
+	$t rm $(APP)/EXPECT
+
+core-deps-dep-built-full: build clean
+
+	$i "Bootstrap a new OTP library named $(APP)"
+	$t mkdir $(APP)/
+	$t cp ../erlang.mk $(APP)/
+	$t $(MAKE) -C $(APP) -f erlang.mk bootstrap-lib $v
+
+	$i "Add cowlib to the list of dependencies"
+	$t perl -ni.bak -e 'print;if ($$.==1) {print "DEPS = cowlib\n"}' $(APP)/Makefile
+
+	$i "Build the application"
+	$t $(MAKE) -C $(APP) $v
+
+	$i "Touch one cowlib file to mark it for recompilation"
+	$t $(SLEEP)
+	$t touch $(APP)/deps/cowlib/src/cow_http.erl
+
+	$i "Check that cowlib is rebuilt with FULL=1"
+	$t printf "%s\n" \
+		$(APP)/deps/cowlib/cowlib.d \
+		$(APP)/deps/cowlib/ebin/cowlib.app \
+		$(APP)/deps/cowlib/ebin/cow_http.beam \
+		$(APP)/deps/cowlib/ebin/dep_built | sort > $(APP)/EXPECT
+	$t $(SLEEP)
+	$t $(MAKE) -C $(APP) FULL=1 $v
+# Files in .git might end up modified due to the id generation in the .app file.
+	$t find $(APP)/deps/cowlib -type f -newer $(APP)/EXPECT | grep -v ".git" | sort | diff $(APP)/EXPECT -
+	$t rm $(APP)/EXPECT
+
+core-deps-dep-built-ln: build clean
+
+	$i "Bootstrap a new OTP library named $(APP)"
+	$t mkdir $(APP)/
+	$t cp ../erlang.mk $(APP)/
+	$t $(MAKE) -C $(APP) -f erlang.mk bootstrap-lib $v
+
+	$i "Add cowlib to the list of dependencies"
+	$t perl -ni.bak -e 'print;if ($$.==1) {print "DEPS = cowlib\n"}' $(APP)/Makefile
+
+	$i "Clone cowlib manually inside $(APP)"
+	$t git clone -q https://github.com/ninenines/cowlib $(APP)/cowlib
+
+	$i "Link to cowlib instead of fetching the dependency"
+	$t mkdir -p $(APP)/deps
+	$t ln -s ../cowlib $(APP)/deps/cowlib
+
+	$i "Build the application"
+	$t $(MAKE) -C $(APP) $v
+
+	$i "Touch one cowlib file to mark it for recompilation"
+	$t $(SLEEP)
+	$t touch $(APP)/deps/cowlib/src/cow_http.erl
+
+	$i "Check that cowlib is rebuilt; symlinked deps don't create dep_built"
+	$t printf "%s\n" \
+		$(APP)/cowlib/cowlib.d \
+		$(APP)/cowlib/ebin/cowlib.app \
+		$(APP)/cowlib/ebin/cow_http.beam | sort > $(APP)/EXPECT
+	$t $(SLEEP)
+	$t $(MAKE) -C $(APP) $v
+# Files in .git might end up modified due to the id generation in the .app file.
+	$t find $(APP)/cowlib -type f -newer $(APP)/EXPECT | grep -v ".git" | sort | diff $(APP)/EXPECT -
+	$t rm $(APP)/EXPECT
+
 core-deps-dep-commit: build clean
 
 	$i "Bootstrap a new OTP library named $(APP)"