[Bug 1882497] Re: Missing 'cmp' utility makes build take 10 times as long

[Laurent Vivier]

cmp is used in the makefiles.

And there is some kind of warning during build if it is missing:

/bin/sh: cmp: command not found

But perhaps it should abort the build in this case.

Something like that helps:

diff --git a/Makefile b/Makefile
index 40e4f7677bde..05e029bd99db 100644
--- a/Makefile
+++ b/Makefile
@@ -482,6 +482,7 @@ include $(SRC_PATH)/tests/Makefile.include
 all: $(DOCS) $(if $(BUILD_DOCS),sphinxdocs) $(TOOLS) $(HELPERS-y) recurse-all 
modules $(vhost-user-json-y)
 
 qemu-version.h: FORCE
+       @type cmp
        $(call quiet-command, \
                 (printf '#define QEMU_PKGVERSION "$(QEMU_PKGVERSION)"\n'; \
                printf '#define QEMU_FULL_VERSION "$(FULL_VERSION)"\n'; \

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https://bugs.launchpad.net/bugs/1882497

Title:
  Missing 'cmp' utility makes build take 10 times as long

Status in QEMU:
  New

Bug description:
  I have been doing some work cross compiling qemu for Windows using a
  minimal Fedora container. Recently I started hitting some timeouts on
  the CI service and noticed a build of all targets was going over 1
  hour.

  It seems like the 'cmp' utility from diffutils is used somewhere in
  the process and if it's missing, either a configure or a make gets run
  way too many times - I'll try to pull logs from the CI system at some
  stage soon.

  Could a warning or error be added if cmp is missing?

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