Upstream: fixed proxy_no_cache when caching errors. Caching errors, notably intercepted errors and internally generated 502/504 errors, as well as handling of cache revalidation with 304, did not take into account u->conf->no_cache predicates configured. As a result, an error might be cached even if configuration explicitly says not to. Fix is to check u->conf->no_cache in these cases. To simplify usage in multiple places, checking u->conf->no_cache is now done in a separate function. As a minor optimization, u->conf->no_cache is only checked if u->cacheable is set. As a side effect, this change also fixes caching errors after proxy_cache_bypass. Also, during cache revalidation u->cacheable is now tested, so 304 responses which disable caching won't extend cacheability of stored responses. Additionally, when caching internally generated 502/504 errors u->cacheable is now explicitly updated from u->headers_in.no_cache and u->headers_in.expired, restoring the behaviour before 8041:0784ab86ad08 (1.23.0) when an error happens while reading the response headers. Reported by Kirill A. Korinsky, https://freenginx.org/pipermail/nginx/2024-April/000082.html

VER=	$(shell grep 'define NGINX_VERSION' src/core/nginx.h		\
		| sed -e 's/^.*"\(.*\)".*/\1/')
NGINX=	freenginx-$(VER)
TEMP=	tmp
XSLS?=	xslscript.pl


all:		changes

changes:	$(TEMP)/$(NGINX)/CHANGES.ru				\
		$(TEMP)/$(NGINX)/CHANGES


$(TEMP)/$(NGINX)/CHANGES.ru:	docs/dtd/changes.dtd			\
				docs/xml/nginx/changes.xml		\
				docs/xml/change_log_conf.xml		\
				docs/xslt/changes.xslt

	mkdir -p $(TEMP)/$(NGINX)

	xmllint --noout --valid docs/xml/nginx/changes.xml
	xsltproc --stringparam lang ru					\
		-o $@ docs/xslt/changes.xslt docs/xml/nginx/changes.xml


$(TEMP)/$(NGINX)/CHANGES:	docs/dtd/changes.dtd			\
				docs/xml/nginx/changes.xml		\
				docs/xml/change_log_conf.xml		\
				docs/xslt/changes.xslt

	mkdir -p $(TEMP)/$(NGINX)

	xmllint --noout --valid docs/xml/nginx/changes.xml
	xsltproc --stringparam lang en					\
		-o $@ docs/xslt/changes.xslt docs/xml/nginx/changes.xml


docs/xslt/changes.xslt:		docs/xsls/changes.xsls

	$(XSLS) -o $@ $<