[PATCH v3 13/49] perf build: Make mypy build test opt-out (NO_MYPY=1)

[Ian Rogers <irogers@google.com>]

Commit 168910d0f937 ("perf build: Add mypy build tests") added a
compile-time mypy type check for Python files in tools/perf, but left it
opt-in via MYPY=1.

Now that mypy issues across tools/perf/python, tools/perf/pmu-events,
and tools/perf/tests/shell/lib have been cleaned up, enable the mypy
check by default when mypy is installed on the system, with an opt-out
via NO_MYPY=1 (matching NO_SHELLCHECK=1 and other perf build feature
flags). Also configure MYPYPATH in Makefile.perf so scripts can resolve
perf.pyi type stubs and local modules, pass --ignore-missing-imports so
optional third-party packages do not fail default builds, and remove
*.mypy_log files during `make clean`.

Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/Build            |  2 +-
 tools/perf/Makefile.perf    | 26 ++++++++++++++++++++++----
 tools/perf/pmu-events/Build |  2 +-
 tools/perf/tests/Build      |  2 +-
 tools/perf/util/Build       |  2 +-
 5 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/tools/perf/Build b/tools/perf/Build
index e18c80a5c1bc..37d603faea6d 100644
--- a/tools/perf/Build
+++ b/tools/perf/Build
@@ -88,7 +88,7 @@ endif
 
 $(OUTPUT)%.mypy_log: %
 	$(call rule_mkdir)
-	$(Q)$(call echo-cmd,test)mypy "$<" > $@ || (cat $@ && rm $@ && false)
+	$(Q)$(call echo-cmd,test)$(MYPY) "$<" > $@ || (cat $@ && rm $@ && false)
 
 perf-y += $(MYPY_TEST_LOGS)
 
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 2438b40eaaec..c7cade270b23 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -129,6 +129,8 @@ include ../scripts/utilities.mak
 # Define GEN_VMLINUX_H to generate vmlinux.h from the BTF.
 #
 # Define NO_SHELLCHECK if you do not want to run shellcheck during build
+#
+# Define NO_MYPY if you do not want to run mypy during build
 
 # As per kernel Makefile, avoid funny character set dependencies
 unexport LC_ALL
@@ -262,9 +264,24 @@ ifneq ($(SHELLCHECK),)
   endif
 endif
 
-# Runs mypy on perf python files
-ifeq ($(MYPY),1)
-  MYPY := $(shell which mypy 2> /dev/null)
+# Runs mypy on perf python files.
+# Wait until after the fixdep bootstrap sub-make (force_fixdep != 1) so
+# command-line overrides (MYPY=1, MYPY=/custom/path, NO_MYPY=1) reach the
+# main Makefile.perf pass intact, then strip MYPY=% from MAKEOVERRIDES
+# (substituting escaped spaces so multi-word overrides like MYPY="mypy --strict"
+# are removed as a single token) so child Makefile.build sub-makes inherit the
+# MYPYPATH-wrapped export MYPY environment variable.
+ifneq ($(force_fixdep),1)
+  MAKEOVERRIDES := $(subst __SPACE__,\ ,$(filter-out MYPY=%,$(subst \ ,__SPACE__,$(MAKEOVERRIDES))))
+  ifeq ($(NO_MYPY),1)
+    override MYPY :=
+  else ifeq ($(filter-out 1,$(MYPY)),)
+    override MYPY := $(shell which mypy 2> /dev/null)
+  endif
+
+  ifneq ($(MYPY),)
+    override MYPY := MYPYPATH=$(srctree)/tools/perf/python $(MYPY) --ignore-missing-imports
+  endif
 endif
 
 # Runs pylint on perf python files
@@ -948,7 +965,8 @@ clean:: $(LIBAPI)-clean $(LIBBPF)-clean $(LIBSUBCMD)-clean $(LIBSYMBOL)-clean $(
 	$(call QUIET_CLEAN, core-objs)  $(RM) $(LIBPERF_A) $(OUTPUT)perf-archive \
 		$(OUTPUT)perf-iostat $(LANG_BINDINGS)
 	$(Q)find $(or $(OUTPUT),.) -name '*.o' -delete -o -name '*.a' -delete -o \
-		-name '\.*.cmd' -delete -o -name '\.*.d' -delete -o -name '*.shellcheck_log' -delete
+		-name '\.*.cmd' -delete -o -name '\.*.d' -delete -o -name '*.shellcheck_log' -delete -o \
+		-name '*.mypy_log' -delete
 	$(Q)$(RM) $(OUTPUT).config-detected
 	$(call QUIET_CLEAN, core-progs) $(RM) $(ALL_PROGRAMS) perf perf-read-vdso32 \
 		perf-read-vdsox32 $(OUTPUT)$(LIBJVMTI).so
diff --git a/tools/perf/pmu-events/Build b/tools/perf/pmu-events/Build
index 372773b998e4..c3542e5ae46f 100644
--- a/tools/perf/pmu-events/Build
+++ b/tools/perf/pmu-events/Build
@@ -187,7 +187,7 @@ JEVENTS_DEPS := $(OUT_JSON) $(GEN_JSON) $(JEVENTS_PY) $(METRIC_PY) $(EMPTY_PMU_E
 ifdef MYPY
 define MYPY_RULE
 $(2): $(1)
-	$$(Q)$$(call echo-cmd,test)mypy $(1) > $(2) || (cat $(2) && rm $(2) && false)
+	$$(Q)$$(call echo-cmd,test)$$(MYPY) $(1) > $(2) || (cat $(2) && rm $(2) && false)
 endef
 $(foreach src,$(wildcard pmu-events/*.py), \
     $(eval dest := $(patsubst pmu-events/%,$(OUTPUT)pmu-events/%.mypy_log,$(src))) \
diff --git a/tools/perf/tests/Build b/tools/perf/tests/Build
index 406e48eed1c8..98b05b68fc14 100644
--- a/tools/perf/tests/Build
+++ b/tools/perf/tests/Build
@@ -104,7 +104,7 @@ endif
 
 $(OUTPUT)%.mypy_log: %
 	$(call rule_mkdir)
-	$(Q)$(call echo-cmd,test)mypy "$<" > $@ || (cat $@ && rm $@ && false)
+	$(Q)$(call echo-cmd,test)$(MYPY) "$<" > $@ || (cat $@ && rm $@ && false)
 
 perf-test-y += $(MYPY_TEST_LOGS)
 
diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index d08f2af7d970..71d1f7289d03 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -426,7 +426,7 @@ endif
 
 $(OUTPUT)%.mypy_log: %
 	$(call rule_mkdir)
-	$(Q)$(call echo-cmd,test)mypy "$<" > $@ || (cat $@ && rm $@ && false)
+	$(Q)$(call echo-cmd,test)$(MYPY) "$<" > $@ || (cat $@ && rm $@ && false)
 
 perf-util-y += $(MYPY_TEST_LOGS)
 
-- 
2.56.0.rc1.310.g51773c2048-goog