Move commit distance computation into a separate bash script. (dotnet#16712)

The script does the same thing, except:

* It doesn't use 'bc', but instead bash's intrinsic math support: '$((1+2))' -
  because when we execute in bash on Windows, 'bc' might not be available.
* It's easier to debug.

This fixes a problem when we need to compute these values on Windows in CI.

Author: rolfbjarne

Make.config

@@ -20,19 +20,7 @@ NUGET_VERSION_STABLE_COMMIT_DISTANCE_START=0
 
 -include $(TOP)/Make.config.inc
 $(TOP)/Make.config.inc: $(TOP)/Make.config $(TOP)/mk/mono.mk
-	@rm -f $@
-	@printf "IOS_COMMIT_DISTANCE:=$(shell LANG=C; export LANG && git --git-dir $(TOP)/.git log `git --git-dir $(TOP)/.git blame -- ./Make.versions HEAD | grep IOS_PACKAGE_VERSION= | sed 's/ .*//' `..HEAD --oneline | wc -l | sed 's/ //g')\n" >> $@
-	@printf "MAC_COMMIT_DISTANCE:=$(shell LANG=C; export LANG && git --git-dir $(TOP)/.git log `git --git-dir $(TOP)/.git blame -- ./Make.versions HEAD | grep MAC_PACKAGE_VERSION= | sed 's/ .*//' `..HEAD --oneline | wc -l | sed 's/ //g')\n" >> $@
-	@#
-	@printf "IOS_NUGET_COMMIT_DISTANCE:=$(shell LANG=C; export LANG; git --git-dir $(TOP)/.git log `git --git-dir $(TOP)/.git blame -- ./Make.versions HEAD | grep IOS_NUGET_OS_VERSION= | sed 's/ .*//' `..HEAD --oneline | wc -l | sed -e 's/ //g' -e "s/^/$(NUGET_VERSION_COMMIT_DISTANCE_START)+/" | bc)\\n" >> $@
-	@printf "TVOS_NUGET_COMMIT_DISTANCE:=$(shell LANG=C; export LANG; git --git-dir $(TOP)/.git log `git --git-dir $(TOP)/.git blame -- ./Make.versions HEAD | grep TVOS_NUGET_OS_VERSION= | sed 's/ .*//' `..HEAD --oneline | wc -l | sed -e 's/ //g' -e "s/^/$(NUGET_VERSION_COMMIT_DISTANCE_START)+/" | bc)\\n" >> $@
-	@printf "WATCHOS_NUGET_COMMIT_DISTANCE:=$(shell LANG=C; export LANG; git --git-dir $(TOP)/.git log `git --git-dir $(TOP)/.git blame -- ./Make.versions HEAD | grep WATCHOS_NUGET_OS_VERSION= | sed 's/ .*//' `..HEAD --oneline | wc -l | sed -e 's/ //g' -e "s/^/$(NUGET_VERSION_COMMIT_DISTANCE_START)+/" | bc)\\n" >> $@
-	@printf "MACOS_NUGET_COMMIT_DISTANCE:=$(shell LANG=C; export LANG; git --git-dir $(TOP)/.git log `git --git-dir $(TOP)/.git blame -- ./Make.versions HEAD | grep MACOS_NUGET_OS_VERSION= | sed 's/ .*//' `..HEAD --oneline | wc -l | sed -e 's/ //g' -e "s/^/$(NUGET_VERSION_COMMIT_DISTANCE_START)+/" | bc)\\n" >> $@
-	@printf "MACCATALYST_NUGET_COMMIT_DISTANCE:=$(shell LANG=C; export LANG; git --git-dir $(TOP)/.git log `git --git-dir $(TOP)/.git blame -- ./Make.versions HEAD | grep MACCATALYST_NUGET_OS_VERSION= | sed 's/ .*//' `..HEAD --oneline | wc -l | sed -e 's/ //g' -e "s/^/$(NUGET_VERSION_COMMIT_DISTANCE_START)+/" | bc)\\n" >> $@
-	@printf "NUGET_STABLE_COMMIT_DISTANCE:=$(shell LANG=C; export LANG; git --git-dir $(TOP)/.git log `git --git-dir $(TOP)/.git blame -L '/^[#[:blank:]]*NUGET_RELEASE_BRANCH=/,+1' -- ./Make.config HEAD | sed 's/ .*//' `..HEAD --oneline | wc -l | sed -e 's/ //g' -e "s/^/$(NUGET_VERSION_STABLE_COMMIT_DISTANCE_START)+/" | bc)\\n" >> $@
-	@#
-	@if which ccache > /dev/null 2>&1; then printf "ENABLE_CCACHE=1\nexport CCACHE_BASEDIR=$(abspath $(TOP)/..)\n" >> $@; echo "Found ccache on the system, enabling it"; fi
-	@if test -d $(TOP)/../maccore; then printf "ENABLE_XAMARIN=1\n" >> $@; echo "Detected the maccore repository, automatically enabled the Xamarin build"; fi
+	$(Q) cd $(TOP) && ALL_DOTNET_PLATFORMS="$(ALL_DOTNET_PLATFORMS)" ./create-make-config.sh
 
 include $(TOP)/Make.versions
 

create-make-config.sh

@@ -0,0 +1,49 @@
+#!/bin/bash -eu
+
+set -o pipefail
+IFS=$'\n\t '
+
+OUTPUT=Make.config.inc
+OUTPUT_FILE=Make.config.inc.tmp
+
+rm -f "$OUTPUT_FILE" "$OUTPUT"
+
+LANG=C
+export LANG
+
+# Support for hardcoding a commit distance start offset.
+NUGET_VERSION_COMMIT_DISTANCE_START=0
+NUGET_VERSION_STABLE_COMMIT_DISTANCE_START=0
+
+# Compute commit distances
+printf "IOS_COMMIT_DISTANCE:=$(git log $(git blame -- ./Make.versions HEAD | grep IOS_PACKAGE_VERSION= | sed 's/ .*//' )..HEAD --oneline | wc -l | sed 's/ //g')\n" >> "$OUTPUT_FILE"
+printf "MAC_COMMIT_DISTANCE:=$(git log $(git blame -- ./Make.versions HEAD | grep MAC_PACKAGE_VERSION= | sed 's/ .*//' )..HEAD --oneline | wc -l | sed 's/ //g')\n" >> "$OUTPUT_FILE"
+
+for platform in $ALL_DOTNET_PLATFORMS; do
+	PLATFORM=$(echo "$platform" | tr '[:lower:]' '[:upper:]')
+	COMMIT=$(git blame -- ./Make.versions HEAD | grep "${PLATFORM}_NUGET_OS_VERSION=" | sed 's/ .*//')
+	COMMIT_DISTANCE=$(git log "$COMMIT..HEAD" --oneline | wc -l | sed -e 's/ //g')
+	TOTAL_DISTANCE=$((NUGET_VERSION_COMMIT_DISTANCE_START+COMMIT_DISTANCE))
+	printf "${PLATFORM}_NUGET_COMMIT_DISTANCE:=$TOTAL_DISTANCE\\n" >> "$OUTPUT_FILE"
+done
+
+STABLE_COMMIT=$(git blame -L '/^[#[:blank:]]*NUGET_RELEASE_BRANCH=/,+1' -- ./Make.config HEAD | sed 's/ .*//')
+STABLE_COMMIT_DISTANCE=$(git log "$STABLE_COMMIT..HEAD" --oneline | wc -l | sed -e 's/ //g')
+STABLE_TOTAL_DISTANCE=$((STABLE_COMMIT_DISTANCE+NUGET_VERSION_STABLE_COMMIT_DISTANCE_START))
+
+printf "NUGET_STABLE_COMMIT_DISTANCE:=$STABLE_TOTAL_DISTANCE\\n" >> "$OUTPUT_FILE"
+
+# Detect ccache
+if which ccache > /dev/null 2>&1; then
+	printf "ENABLE_CCACHE=1\n" >> "$OUTPUT_FILE"
+	printf "export CCACHE_BASEDIR=$(cd .. && pwd)\n" >> "$OUTPUT_FILE"
+	echo "Found ccache on the system, enabling it"
+fi
+
+# Detect maccore / xamarin
+if test -d ../maccore; then
+	printf "ENABLE_XAMARIN=1\n" >> "$OUTPUT_FILE"
+	echo "Detected the maccore repository, automatically enabled the Xamarin build"
+fi
+
+mv "$OUTPUT_FILE" "$OUTPUT"