In commit b0fcc6fc7fc1 ("build: rebuild build.ninja using
"meson setup --reconfigure"", 2023-05-19) I changed the build.ninja
rule in the Makefile to use "meson setup" so that the Makefile would
pick up a changed path to the meson binary.
However, there was a reason why build.ninja was rebuilt using $(NINJA)
itself. Namely, ninja has its own cache of file modification times,
and if it does not know about the modification that was done outside
its control, it will *also* try to regenerate build.ninja. This can be
simply by running "make" on a fresh tree immediately after "configure";
that will trigger an unnecessary meson run.
So, apply a refinement to the rule in order to cover both cases:
- track the meson binary that was used (and that is embedded in
build.ninja's reconfigure rules); to do this, write build.ninja.stamp
right after executing meson successfully
- if it changed, force usage of "$(MESON) setup --reconfigure" to
update the path in the reconfigure rule
- if it didn't change, use "$(NINJA) build.ninja" just like before
commit b0fcc6fc7fc1.
Reported-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
Makefile | 17 +++++++++++++----
configure | 1 +
2 files changed, 14 insertions(+), 4 deletions(-)
diff --git a/Makefile b/Makefile
index b22bf6fba12..804a5681e0a 100644
--- a/Makefile
+++ b/Makefile
@@ -83,16 +83,17 @@ config-host.mak: $(SRC_PATH)/configure
$(SRC_PATH)/scripts/meson-buildoptions.sh
@if test -f meson-private/coredata.dat; then \
./config.status --skip-meson; \
else \
- ./config.status && touch build.ninja.stamp; \
+ ./config.status; \
fi
# 2. meson.stamp exists if meson has run at least once (so ninja reconfigure
# works), but otherwise never needs to be updated
+
meson-private/coredata.dat: meson.stamp
meson.stamp: config-host.mak
@touch meson.stamp
-# 3. ensure generated build files are up-to-date
+# 3. ensure meson-generated build files are up-to-date
ifneq ($(NINJA),)
Makefile.ninja: build.ninja
@@ -106,11 +107,19 @@ Makefile.ninja: build.ninja
endif
ifneq ($(MESON),)
-# A separate rule is needed for Makefile dependencies to avoid -n
+# The path to meson always points to pyvenv/bin/meson, but the absolute
+# paths could change. In that case, force a regeneration of build.ninja.
+# Note that this invocation of $(NINJA), just like when Make rebuilds
+# Makefiles, does not include -n.
build.ninja: build.ninja.stamp
$(build-files):
build.ninja.stamp: meson.stamp $(build-files)
- $(MESON) setup --reconfigure $(SRC_PATH) && touch $@
+ @if test "$$(cat build.ninja.stamp)" = "$(MESON)" && test -n
"$(NINJA)"; then \
+ $(NINJA) build.ninja; \
+ else \
+ echo "$(MESON) setup --reconfigure $(SRC_PATH)"; \
+ $(MESON) setup --reconfigure $(SRC_PATH); \
+ fi && echo "$(MESON)" > $@
Makefile.mtest: build.ninja scripts/mtest2make.py
$(MESON) introspect --targets --tests --benchmarks | $(PYTHON)
scripts/mtest2make.py > $@
diff --git a/configure b/configure
index 8a638dd82ae..cbdb389dc95 100755
--- a/configure
+++ b/configure
@@ -1894,6 +1894,7 @@ if test "$skip_meson" = no; then
if test "$?" -ne 0 ; then
error_exit "meson setup failed"
fi
+ echo "$meson" > build.ninja.stamp
else
if test -f meson-private/cmd_line.txt; then
# Adjust old command line options that were removed