Documentation: wire up sanity checks for Meson

Wire up sanity checks for Meson to verify that no man pages are missing.
This check is similar to the same check we already have for our tests.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/.gitignore

@@ -12,6 +12,7 @@ cmds-*.txt
 mergetools-*.txt
 SubmittingPatches.txt
 tmp-doc-diff/
+tmp-meson-diff/
 GIT-ASCIIDOCFLAGS
 /.build/
 /GIT-EXCLUDED-PROGRAMS

Documentation/Makefile

@@ -339,6 +339,7 @@ clean:
 	$(RM) $(cmds_txt) $(mergetools_txt) *.made
 	$(RM) GIT-ASCIIDOCFLAGS
 	$(RM) asciidoc.conf asciidoctor-extensions.rb
+	$(RM) -rf tmp-meson-diff
 
 docinfo.html: docinfo-html.in
 	$(QUIET_GEN)$(RM) $@ && cat $< >$@
@@ -494,6 +495,20 @@ lint-docs-fsck-msgids: $(LINT_DOCS_FSCK_MSGIDS)
 lint-docs-manpages:
 	$(QUIET_GEN)./lint-manpages.sh
 
+.PHONY: lint-docs-meson
+lint-docs-meson:
+	@# awk acts up when trying to match single quotes, so we use \047 instead.
+	@mkdir -p tmp-meson-diff && \
+	awk "/^manpages = {$$/ {flag=1 ; next } /^}$$/ { flag=0 } flag { gsub(/^  \047/, \"\"); gsub(/\047 : [157],\$$/, \"\"); print }" meson.build | \
+		grep -v -e '#' -e '^$$' | \
+		sort >tmp-meson-diff/meson.txt && \
+	ls git*.txt scalar.txt | grep -v -e git-bisect-lk2009.txt -e git-tools.txt >tmp-meson-diff/actual.txt && \
+	if ! cmp tmp-meson-diff/meson.txt tmp-meson-diff/actual.txt; then \
+		echo "Meson man pages differ from actual man pages:"; \
+		diff -u tmp-meson-diff/meson.txt tmp-meson-diff/actual.txt; \
+		exit 1; \
+	fi
+
 ## Lint: list of targets above
 .PHONY: lint-docs
 lint-docs: lint-docs-fsck-msgids
@@ -501,6 +516,7 @@ lint-docs: lint-docs-gitlink
 lint-docs: lint-docs-man-end-blurb
 lint-docs: lint-docs-man-section-order
 lint-docs: lint-docs-manpages
+lint-docs: lint-docs-meson
 
 ifeq ($(wildcard po/Makefile),po/Makefile)
 doc-l10n install-l10n::

Documentation/meson.build

@@ -471,3 +471,34 @@ if get_option('docs').contains('html')
   subdir('howto')
   subdir('technical')
 endif
+
+# Sanity check that we are not missing any tests present in 't/'. This check
+# only runs once at configure time and is thus best-effort, only. Furthermore,
+# it only verifies man pages for the sake of simplicity.
+configured_manpages = manpages.keys() + [ 'git-bisect-lk2009.txt', 'git-tools.txt' ]
+actual_manpages = run_command(shell, '-c', 'ls git*.txt scalar.txt',
+  check: true,
+  env: script_environment,
+).stdout().strip().split('\n')
+
+if configured_manpages != actual_manpages
+  missing_manpage = [ ]
+  foreach actual_manpage : actual_manpages
+    if actual_manpage not in configured_manpages
+      missing_manpage += actual_manpage
+    endif
+  endforeach
+  if missing_manpage.length() > 0
+    error('Man page found, but not configured:\n\n - ' + '\n - '.join(missing_manpage))
+  endif
+
+  superfluous_manpage = [ ]
+  foreach configured_manpage : configured_manpages
+    if configured_manpage not in actual_manpages
+      superfluous_manpage += configured_manpage
+    endif
+  endforeach
+  if superfluous_manpage.length() > 0
+    error('Man page configured, but not found:\n\n - ' + '\n - '.join(superfluous_manpage))
+  endif
+endif