From b5b2a4b87b6f0c11831766cad8384d2f47a93e6d Mon Sep 17 00:00:00 2001
From: Alex Boten <aboten@lightstep.com>
Date: Mon, 25 Sep 2023 12:02:30 -0700
Subject: [PATCH] [chore] use multimod diff (#8513)

This is revert-ing the revert of
https://github.com/open-telemetry/opentelemetry-collector/pull/8024.
This also inverses the return of `check-changes` to match the original
behaviour.

Fixes #8149

---------

Signed-off-by: Alex Boten <aboten@lightstep.com>
---
 Makefile | 42 +++++-------------------------------------
 1 file changed, 5 insertions(+), 37 deletions(-)

diff --git a/Makefile b/Makefile
index de19ea41afc..df15bd39f3a 100644
--- a/Makefile
+++ b/Makefile
@@ -433,43 +433,11 @@ push-tags: $(MULTIMOD)
 
 .PHONY: check-changes
 check-changes: $(YQ)
-ifndef MODSET
-	@echo "MODSET not defined"
-	@echo "usage: make check-changes PREVIOUS_VERSION=<version eg 0.52.0> MODSET=beta"
-	exit 1
-endif
-ifndef PREVIOUS_VERSION
-	@echo "PREVIOUS_VERSION not defined"
-	@echo "usage: make check-changes PREVIOUS_VERSION=<version eg 0.52.0> MODSET=beta"
-	exit 1
-else
-ifeq (, $(findstring v,$(PREVIOUS_VERSION)))
-NORMALIZED_PREVIOUS_VERSION="v$(PREVIOUS_VERSION)"
-else
-NORMALIZED_PREVIOUS_VERSION="$(PREVIOUS_VERSION)"
-endif
-endif
-	@all_submods=$$($(YQ) e '.module-sets.*.modules[] | select(. != "go.opentelemetry.io/collector")' versions.yaml | sed 's/^go\.opentelemetry\.io\/collector\///'); \
-	mods=$$($(YQ) e '.module-sets.$(MODSET).modules[]' versions.yaml | sed 's/^go\.opentelemetry\.io\/collector\///'); \
-	changed_files=""; \
-	for mod in $${mods}; do \
-		if [ "$${mod}" == "go.opentelemetry.io/collector" ]; then \
-			changed_files+=$$(git diff --name-only $(NORMALIZED_PREVIOUS_VERSION) -- $$(printf '%s\n' $${all_submods[@]} | sed 's/^/:!/' | paste -sd' ' -) | grep -E '.+\.go$$'); \
-		elif ! git rev-parse --quiet --verify $${mod}/$(NORMALIZED_PREVIOUS_VERSION) >/dev/null; then \
-			echo "Module $${mod} does not have a $(NORMALIZED_PREVIOUS_VERSION) tag"; \
-			echo "$(MODSET) release is required."; \
-			exit 0; \
-		else \
-			changed_files+=$$(git diff --name-only $${mod}/$(NORMALIZED_PREVIOUS_VERSION) -- $${mod} | grep -E '.+\.go$$'); \
-		fi; \
-	done; \
-	if [ -n "$${changed_files}" ]; then \
-		echo "The following files changed in $(MODSET) modules since $(NORMALIZED_PREVIOUS_VERSION): $${changed_files}"; \
-	else \
-		echo "No $(MODSET) modules have changed since $(NORMALIZED_PREVIOUS_VERSION)"; \
-		echo "No need to release $(MODSET)."; \
-		exit 1; \
-	fi
+	# NOTE: ! inverses the return code of multimod diff. This is
+	# because prepare-release expects a 0 if there are diffs and
+	# non-0 if there are no diffs, which is the inverse of most
+	# diff tools
+	! $(MULTIMOD) diff -p $(PREVIOUS_VERSION) -m $(MODSET)
 
 .PHONY: prepare-release
 prepare-release: