build: Ensure the installed pre-push git hook matches its source.

* Makefile.am ($(GIT_HOOKS_DIR)/pre-push): Make a phony target, and copy file
when the target differs from its prerequisite.

Fixes: #7645
Reported-by: Gábor Udvari <mail@gaborudvari.com>
Change-Id: I6b5f677afe59c25a4d8905da814af4bbd91fb401

1 files changed, 8 insertions, 0 deletions

diff --git a/Makefile.am b/Makefile.am
index 79575c7dfdb..d349fcaa383 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1281,6 +1281,14 @@ $(GIT_HOOKS_DIR):
 $(GIT_HOOKS_DIR)/%: etc/git/% | $(GIT_HOOKS_DIR)/
         if [ -n "$(GIT_HOOKS_DIR)" ]; then cp "$<" "$@"; fi
 
+# Special-case the pre-push hook installation, to ensure it is always
+# up-to-date with its source.
+.PHONY: $(GIT_HOOKS_DIR)/pre-push
+$(GIT_HOOKS_DIR)/pre-push: etc/git/pre-push | $(GIT_HOOKS_DIR)
+        @if [ -n "$(GIT_HOOKS_DIR)" ]; then \
+          cmp "--silent" "$<" "$@" || cp "$<" "$@"; \
+        fi
+
 $(GIT_CONFIG_FILE): etc/git/gitconfig
         if [ -n "$(GIT_CONFIG_FILE)" ]; then \
           git config --fixed-value --replace-all include.path \