Hi Peff, On Sat, 4 Apr 2020, Jeff King wrote: > On Sat, Apr 04, 2020 at 03:38:00PM +0200, Johannes Schindelin wrote: > > > > [1/2]: Makefile: avoid running curl-config multiple times > > > [2/2]: Makefile: use curl-config --cflags > > > > I _suspect_ that this is responsible for the build failure > > > > make: curl-config: Command not found > > > > at https://github.com/git/git/runs/556459415#step:4:674 > > > > Do we need this to fix this? > > Hmm, yeah. It's an unfortunate side effect of the ":=" assignment to > stop repeatedly invoking curl-config. Now it's only invoked once, but > it's _always_ once, even if we're not building anything that needs it. > > I wonder if there's a way to expand a Makefile variable lazily, but only > once...aha, with some help from the Internet, I came up with the patch > below. Thanks, that would work. > > -- snip -- > > diff --git a/ci/test-documentation.sh b/ci/test-documentation.sh > > index de41888430a..325b4cc6185 100755 > > --- a/ci/test-documentation.sh > > +++ b/ci/test-documentation.sh > > @@ -11,6 +11,7 @@ filter_log () { > > -e '/^ \* new asciidoc flags$/d' \ > > -e '/stripped namespace before processing/d' \ > > -e '/Attributed.*IDs for element/d' \ > > + -e '/curl-config: Command not found/d' \ > > "$1" > > } > > Yes, this works, but it's rather unfortunate that we're invoking > curl-config when it's not needed. Perhaps using NO_CURL in the > documentation job would be better. But if the patch below isn't too > disgusting, I think I prefer that approach (because it helps _any_ > top-level make invocation that isn't actually building http binaries). I believe that we do need to avoid `NO_CURL` lest we miss out on documentation mismatches in the `check-docs` target. Ciao, Dscho > Junio, you may want to hold off on moving jk/build-with-right-curl to > next until we resolve this one way or the other. > > -- >8 -- > Subject: [PATCH] Makefile: avoid running curl-config unnecessarily > > Commit 94a88e2524 (Makefile: avoid running curl-config multiple times, > 2020-03-26) put the call to $(CURL_CONFIG) into a "simple" variable > which is expanded immediately, rather than expanding it each time it's > needed. However, that also means that we expand it whenever the Makefile > is parsed, whether we need it or not. > > This is wasteful, but also breaks the ci/test-documentation.sh job, as > it does not have curl at all and complains about the extra messages to > stderr. An easy way to see it is just: > > $ make CURL_CONFIG=does-not-work check-builtins > make: does-not-work: Command not found > make: does-not-work: Command not found > GIT_VERSION = 2.26.0.108.gb3f3f45f29 > make: does-not-work: Command not found > make: does-not-work: Command not found > ./check-builtins.sh > > We can get the best of both worlds if we're willing to accept a little > Makefile hackery. Courtesy of the article at: > > http://make.mad-scientist.net/deferred-simple-variable-expansion/ > > this patch uses a lazily-evaluated recursive variable which replaces its > contents with an immediately assigned simple one on first use. > > Reported-by: Johannes Schindelin <Johannes.Schindelin@xxxxxx> > Signed-off-by: Jeff King <peff@xxxxxxxx> > --- > This is our first use of eval in the Makefile, but that goes back to GNU > make v3.80, which is from 2002. I think that should be OK. > > If this inlining is too gross, we could probably contain it in a > function where callers would do something like: > > $(eval lazy-shell-var, CURL_LDFLAGS, $(CURL_CONFIG) --libs) > > That's better in the sense that there's less gobbledygook at each > callsite, but worse in that it obscures the fact that it's a variable > assignment. I'd probably consider going that direction if we started > growing more use-cases than these two. > > We could probably also stuff this into a sh > Makefile | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/Makefile b/Makefile > index 5099f6a8f8..97dbdcd201 100644 > --- a/Makefile > +++ b/Makefile > @@ -1366,12 +1366,12 @@ else > endif > > ifndef CURL_LDFLAGS > - CURL_LDFLAGS := $(shell $(CURL_CONFIG) --libs) > + CURL_LDFLAGS = $(eval CURL_LDFLAGS := $$(shell $$(CURL_CONFIG) --libs))$(CURL_LDFLAGS) > endif > CURL_LIBCURL += $(CURL_LDFLAGS) > > ifndef CURL_CFLAGS > - CURL_CFLAGS := $(shell $(CURL_CONFIG) --cflags) > + CURL_CFLAGS = $(eval CURL_CFLAGS := $$(shell $$(CURL_CONFIG) --cflags))$(CURL_CFLAGS) > endif > BASIC_CFLAGS += $(CURL_CFLAGS) > > -- > 2.26.0.410.gc279fb3cbd > >
