Ninja: Add policy to require explicit custom command byproducts

Add policy CMP0058 to avoid generating 'phony' ninja rules for unknown
custom command dependencies.  This requires projects to specify their
custom command byproducts explicitly.  With this requirement we no
longer have to assume that unknown custom command dependencies are
generated and can instead simply assume they are source files expected
to exist when the build starts.  This is particularly important in
in-source builds.  It is also helpful for out-of-source builds to allow
Ninja to diagnose missing files before running custom command rules that
depend on them.

18 files changed, 95 insertions, 0 deletions

diff --git a/Tests/RunCMake/CMakeLists.txt b/Tests/RunCMake/CMakeLists.txt
index 7cbc9fe..dc63975 100644
--- a/Tests/RunCMake/CMakeLists.txt
+++ b/Tests/RunCMake/CMakeLists.txt
@@ -64,6 +64,9 @@ add_RunCMake_test(CMP0053)
 add_RunCMake_test(CMP0054)
 add_RunCMake_test(CMP0055)
 add_RunCMake_test(CMP0057)
+if(CMAKE_GENERATOR STREQUAL "Ninja")
+  add_RunCMake_test(Ninja)
+endif()
 add_RunCMake_test(CTest)
 
 if(NOT CMake_TEST_EXTERNAL_CMAKE)
diff --git a/Tests/RunCMake/Ninja/CMP0058-NEW-by-build-stdout.txt b/Tests/RunCMake/Ninja/CMP0058-NEW-by-build-stdout.txt
new file mode 100644
index 0000000..8646a13
--- /dev/null
+++ b/Tests/RunCMake/Ninja/CMP0058-NEW-by-build-stdout.txt
@@ -0,0 +1,4 @@
+^[^
+]* Generating output1
+[^
+]* Generating output2$
diff --git a/Tests/RunCMake/Ninja/CMP0058-NEW-by.cmake b/Tests/RunCMake/Ninja/CMP0058-NEW-by.cmake
new file mode 100644
index 0000000..0f77930
--- /dev/null
+++ b/Tests/RunCMake/Ninja/CMP0058-NEW-by.cmake
@@ -0,0 +1,3 @@
+cmake_policy(SET CMP0058 NEW)
+set(byproducts BYPRODUCTS byproduct1a byproduct1b)
+include(CMP0058-common.cmake)
diff --git a/Tests/RunCMake/Ninja/CMP0058-NEW-no-build-result.txt b/Tests/RunCMake/Ninja/CMP0058-NEW-no-build-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/Ninja/CMP0058-NEW-no-build-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/Ninja/CMP0058-NEW-no-build-stderr.txt b/Tests/RunCMake/Ninja/CMP0058-NEW-no-build-stderr.txt
new file mode 100644
index 0000000..fa10109
--- /dev/null
+++ b/Tests/RunCMake/Ninja/CMP0058-NEW-no-build-stderr.txt
@@ -0,0 +1 @@
+ninja: error: 'byproduct1a', needed by 'output2', missing and no known rule to make it
diff --git a/Tests/RunCMake/Ninja/CMP0058-NEW-no.cmake b/Tests/RunCMake/Ninja/CMP0058-NEW-no.cmake
new file mode 100644
index 0000000..582e3d5
--- /dev/null
+++ b/Tests/RunCMake/Ninja/CMP0058-NEW-no.cmake
@@ -0,0 +1,2 @@
+cmake_policy(SET CMP0058 NEW)
+include(CMP0058-common.cmake)
diff --git a/Tests/RunCMake/Ninja/CMP0058-OLD-by-build-stdout.txt b/Tests/RunCMake/Ninja/CMP0058-OLD-by-build-stdout.txt
new file mode 100644
index 0000000..8646a13
--- /dev/null
+++ b/Tests/RunCMake/Ninja/CMP0058-OLD-by-build-stdout.txt
@@ -0,0 +1,4 @@
+^[^
+]* Generating output1
+[^
+]* Generating output2$
diff --git a/Tests/RunCMake/Ninja/CMP0058-OLD-by.cmake b/Tests/RunCMake/Ninja/CMP0058-OLD-by.cmake
new file mode 100644
index 0000000..92a3a0f
--- /dev/null
+++ b/Tests/RunCMake/Ninja/CMP0058-OLD-by.cmake
@@ -0,0 +1,3 @@
+cmake_policy(SET CMP0058 OLD)
+set(byproducts BYPRODUCTS byproduct1a byproduct1b)
+include(CMP0058-common.cmake)
diff --git a/Tests/RunCMake/Ninja/CMP0058-OLD-no-build-stdout.txt b/Tests/RunCMake/Ninja/CMP0058-OLD-no-build-stdout.txt
new file mode 100644
index 0000000..8646a13
--- /dev/null
+++ b/Tests/RunCMake/Ninja/CMP0058-OLD-no-build-stdout.txt
@@ -0,0 +1,4 @@
+^[^
+]* Generating output1
+[^
+]* Generating output2$
diff --git a/Tests/RunCMake/Ninja/CMP0058-OLD-no.cmake b/Tests/RunCMake/Ninja/CMP0058-OLD-no.cmake
new file mode 100644
index 0000000..0326e07
--- /dev/null
+++ b/Tests/RunCMake/Ninja/CMP0058-OLD-no.cmake
@@ -0,0 +1,2 @@
+cmake_policy(SET CMP0058 OLD)
+include(CMP0058-common.cmake)
diff --git a/Tests/RunCMake/Ninja/CMP0058-WARN-by-build-stdout.txt b/Tests/RunCMake/Ninja/CMP0058-WARN-by-build-stdout.txt
new file mode 100644
index 0000000..8646a13
--- /dev/null
+++ b/Tests/RunCMake/Ninja/CMP0058-WARN-by-build-stdout.txt
@@ -0,0 +1,4 @@
+^[^
+]* Generating output1
+[^
+]* Generating output2$
diff --git a/Tests/RunCMake/Ninja/CMP0058-WARN-by.cmake b/Tests/RunCMake/Ninja/CMP0058-WARN-by.cmake
new file mode 100644
index 0000000..6128167
--- /dev/null
+++ b/Tests/RunCMake/Ninja/CMP0058-WARN-by.cmake
@@ -0,0 +1,2 @@
+set(byproducts BYPRODUCTS byproduct1a byproduct1b)
+include(CMP0058-common.cmake)
diff --git a/Tests/RunCMake/Ninja/CMP0058-WARN-no-build-stdout.txt b/Tests/RunCMake/Ninja/CMP0058-WARN-no-build-stdout.txt
new file mode 100644
index 0000000..8646a13
--- /dev/null
+++ b/Tests/RunCMake/Ninja/CMP0058-WARN-no-build-stdout.txt
@@ -0,0 +1,4 @@
+^[^
+]* Generating output1
+[^
+]* Generating output2$
diff --git a/Tests/RunCMake/Ninja/CMP0058-WARN-no-stderr.txt b/Tests/RunCMake/Ninja/CMP0058-WARN-no-stderr.txt
new file mode 100644
index 0000000..439a2d9
--- /dev/null
+++ b/Tests/RunCMake/Ninja/CMP0058-WARN-no-stderr.txt
@@ -0,0 +1,19 @@
+^CMake Warning \(dev\):
+  Policy CMP0058 is not set: Ninja requires custom command byproducts to be
+  explicit.  Run "cmake --help-policy CMP0058" for policy details.  Use the
+  cmake_policy command to set the policy and suppress this warning.
+
+  This project specifies custom command DEPENDS on files in the build tree
+  that are not specified as the OUTPUT or BYPRODUCTS of any
+  add_custom_command or add_custom_target:
+
+   byproduct1a
+   byproduct1b
+
+  For compatibility with versions of CMake that did not have the BYPRODUCTS
+  option, CMake is generating phony rules for such files to convince 'ninja'
+  to build.
+
+  Project authors should add the missing BYPRODUCTS or OUTPUT options to the
+  custom commands that produce these files.
+This warning is for project developers.  Use -Wno-dev to suppress it.
diff --git a/Tests/RunCMake/Ninja/CMP0058-WARN-no.cmake b/Tests/RunCMake/Ninja/CMP0058-WARN-no.cmake
new file mode 100644
index 0000000..7bc66ef
--- /dev/null
+++ b/Tests/RunCMake/Ninja/CMP0058-WARN-no.cmake
@@ -0,0 +1 @@
+include(CMP0058-common.cmake)
diff --git a/Tests/RunCMake/Ninja/CMP0058-common.cmake b/Tests/RunCMake/Ninja/CMP0058-common.cmake
new file mode 100644
index 0000000..9274d58
--- /dev/null
+++ b/Tests/RunCMake/Ninja/CMP0058-common.cmake
@@ -0,0 +1,17 @@
+add_custom_command(
+  OUTPUT output1
+  ${byproducts}
+  COMMAND ${CMAKE_COMMAND} -E touch output1
+  COMMAND ${CMAKE_COMMAND} -E touch byproduct1a
+  COMMAND ${CMAKE_COMMAND} -E touch byproduct1b
+  )
+add_custom_target(Drive1 ALL DEPENDS output1)
+add_custom_command(
+  OUTPUT output2
+  COMMAND ${CMAKE_COMMAND} -E copy output1 output2
+  DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/output1
+          ${CMAKE_CURRENT_BINARY_DIR}/byproduct1a
+          ${CMAKE_CURRENT_BINARY_DIR}/byproduct1b
+  )
+add_custom_target(Drive2 ALL DEPENDS output2)
+add_dependencies(Drive2 Drive1)
diff --git a/Tests/RunCMake/Ninja/CMakeLists.txt b/Tests/RunCMake/Ninja/CMakeLists.txt
new file mode 100644
index 0000000..2a0591e
--- /dev/null
+++ b/Tests/RunCMake/Ninja/CMakeLists.txt
@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 3.2)
+project(${RunCMake_TEST} NONE)
+include(${RunCMake_TEST}.cmake NO_POLICY_SCOPE)
diff --git a/Tests/RunCMake/Ninja/RunCMakeTest.cmake b/Tests/RunCMake/Ninja/RunCMakeTest.cmake
new file mode 100644
index 0000000..64f97bc
--- /dev/null
+++ b/Tests/RunCMake/Ninja/RunCMakeTest.cmake
@@ -0,0 +1,18 @@
+include(RunCMake)
+
+function(run_CMP0058 case)
+  # Use a single build tree for a few tests without cleaning.
+  set(RunCMake_TEST_BINARY_DIR ${RunCMake_BINARY_DIR}/CMP0058-${case}-build)
+  set(RunCMake_TEST_NO_CLEAN 1)
+  file(REMOVE_RECURSE "${RunCMake_TEST_BINARY_DIR}")
+  file(MAKE_DIRECTORY "${RunCMake_TEST_BINARY_DIR}")
+  run_cmake(CMP0058-${case})
+  run_cmake_command(CMP0058-${case}-build ${CMAKE_COMMAND} --build .)
+endfunction()
+
+run_CMP0058(OLD-no)
+run_CMP0058(OLD-by)
+run_CMP0058(WARN-no)
+run_CMP0058(WARN-by)
+run_CMP0058(NEW-no)
+run_CMP0058(NEW-by)