From: Martin Ågren <martin.agren@gmail.com>
Date: Sun, 17 Mar 2019 18:36:00 +0000 (+0100)
Subject: Doc: auto-detect changed build flags
X-Git-Tag: v2.22.0-rc0~101^2~3
X-Git-Url: http://git.ipfire.org/?p=thirdparty%2Fgit.git;a=commitdiff_plain;h=9a71722b4df993475553ea499fdf44dab5fed544

Doc: auto-detect changed build flags

If you build the documentation switching between different options,
e.g., to build with both Asciidoc and Asciidoctor, you'll probably find
yourself running `make -C Documentation clean` either too often (wasting
time) or too rarely (getting mixed builds).

Track the flags we're using in the documentation build, similar to how
the main Makefile tracks CFLAGS and prefix flags. Track ASCIIDOC_COMMON
directly rather than its individual components -- that should make it
harder to forget to update the tracking if/when we modify the build
commands.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---

diff --git a/Documentation/.gitignore b/Documentation/.gitignore
index 3ef54e0adb..bf2bf271b5 100644
--- a/Documentation/.gitignore
+++ b/Documentation/.gitignore
@@ -13,3 +13,4 @@ mergetools-*.txt
 manpage-base-url.xsl
 SubmittingPatches.txt
 tmp-doc-diff/
+GIT-ASCIIDOCFLAGS
diff --git a/Documentation/Makefile b/Documentation/Makefile
index 26a2342bea..b534623012 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -331,6 +331,15 @@ mergetools-list.made: ../git-mergetool--lib.sh $(wildcard ../mergetools/*)
 		show_tool_names can_merge "* " || :' >mergetools-merge.txt && \
 	date >$@
 
+TRACK_ASCIIDOCFLAGS = $(subst ','\'',$(ASCIIDOC_COMMON):$(ASCIIDOC_HTML):$(ASCIIDOC_DOCBOOK))
+
+GIT-ASCIIDOCFLAGS: FORCE
+	@FLAGS='$(TRACK_ASCIIDOCFLAGS)'; \
+	    if test x"$$FLAGS" != x"`cat GIT-ASCIIDOCFLAGS 2>/dev/null`" ; then \
+		echo >&2 "    * new asciidoc flags"; \
+		echo "$$FLAGS" >GIT-ASCIIDOCFLAGS; \
+            fi
+
 clean:
 	$(RM) *.xml *.xml+ *.html *.html+ *.1 *.5 *.7
 	$(RM) *.texi *.texi+ *.texi++ git.info gitman.info
@@ -340,13 +349,14 @@ clean:
 	$(RM) SubmittingPatches.txt
 	$(RM) $(cmds_txt) $(mergetools_txt) *.made
 	$(RM) manpage-base-url.xsl
+	$(RM) GIT-ASCIIDOCFLAGS
 
-$(MAN_HTML): %.html : %.txt asciidoc.conf
+$(MAN_HTML): %.html : %.txt asciidoc.conf GIT-ASCIIDOCFLAGS
 	$(QUIET_ASCIIDOC)$(RM) $@+ $@ && \
 	$(TXT_TO_HTML) -d manpage -o $@+ $< && \
 	mv $@+ $@
 
-$(OBSOLETE_HTML): %.html : %.txto asciidoc.conf
+$(OBSOLETE_HTML): %.html : %.txto asciidoc.conf GIT-ASCIIDOCFLAGS
 	$(QUIET_ASCIIDOC)$(RM) $@+ $@ && \
 	$(TXT_TO_HTML) -o $@+ $< && \
 	mv $@+ $@
@@ -358,12 +368,12 @@ manpage-base-url.xsl: manpage-base-url.xsl.in
 	$(QUIET_XMLTO)$(RM) $@ && \
 	$(XMLTO) -m $(MANPAGE_XSL) $(XMLTO_EXTRA) man $<
 
-%.xml : %.txt asciidoc.conf
+%.xml : %.txt asciidoc.conf GIT-ASCIIDOCFLAGS
 	$(QUIET_ASCIIDOC)$(RM) $@+ $@ && \
 	$(TXT_TO_XML) -d manpage -o $@+ $< && \
 	mv $@+ $@
 
-user-manual.xml: user-manual.txt user-manual.conf
+user-manual.xml: user-manual.txt user-manual.conf GIT-ASCIIDOCFLAGS
 	$(QUIET_ASCIIDOC)$(RM) $@+ $@ && \
 	$(TXT_TO_XML) -d book -o $@+ $< && \
 	mv $@+ $@
@@ -373,7 +383,8 @@ technical/api-index.txt: technical/api-index-skel.txt \
 	$(QUIET_GEN)cd technical && '$(SHELL_PATH_SQ)' ./api-index.sh
 
 technical/%.html: ASCIIDOC_EXTRA += -a git-relative-html-prefix=../
-$(patsubst %,%.html,$(API_DOCS) technical/api-index $(TECH_DOCS)): %.html : %.txt asciidoc.conf
+$(patsubst %,%.html,$(API_DOCS) technical/api-index $(TECH_DOCS)): %.html : %.txt \
+	asciidoc.conf GIT-ASCIIDOCFLAGS
 	$(QUIET_ASCIIDOC)$(TXT_TO_HTML) $*.txt
 
 SubmittingPatches.txt: SubmittingPatches
@@ -430,7 +441,7 @@ $(patsubst %,%.html,$(ARTICLES)) : %.html : %.txt
 WEBDOC_DEST = /pub/software/scm/git/docs
 
 howto/%.html: ASCIIDOC_EXTRA += -a git-relative-html-prefix=../
-$(patsubst %.txt,%.html,$(wildcard howto/*.txt)): %.html : %.txt
+$(patsubst %.txt,%.html,$(wildcard howto/*.txt)): %.html : %.txt GIT-ASCIIDOCFLAGS
 	$(QUIET_ASCIIDOC)$(RM) $@+ $@ && \
 	sed -e '1,/^$$/d' $< | \
 	$(TXT_TO_HTML) - >$@+ && \