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makefilegnu-make

GNU make conditional function $(if ...) inside a user-defined function always evaluates to true

I am trying to write a make function to touch/create an empty file and/or set the permissions, user and group, where possible, or warn if not. However, every conditional check within my function seems to evaluate to true.

The essentials of my Makefile are

INSTALL_USER  := fileUser
INSTALL_GROUP := fileGroup

.PHONY: test
test:
    $(call touchFile,~/test.ini)

define touchFile
$(eval fileName := $(strip $(1)))
-touch $(fileName)
-chmod -c 664 $(fileName)

$(info filename info $(fileName))
$(info $(shell stat -c "%a %U:%G" $(fileName)))

$(if ifeq  "foo" "bar", @echo match is broken, @echo match works)
$(if ifneq "foo" "bar", @echo match works, @echo match is broken)

$(if ifneq ($(shell stat -c %a $(fileName)),664), $(warning Error - $(fileName) does not have expected permissions of 664))
-chgrp -c $(INSTALL_GROUP) $(fileName)
$(if ifneq ($(shell stat -c %G $(fileName)),$(INSTALL_GROUP)), $(warning Error - $(fileName) does not belong to $(INSTALL_GROUP) group))
-chown -c $(INSTALL_USER) $(fileName)
$(if ifneq ($(shell stat -c %U $(fileName)),$(INSTALL_USER)), $(warning Error - $(fileName) does not belong to $(INSTALL_USER) user))
endef

Running make test outputs

filename info ~/test.ini
664 myUserName:myGroup
Makefile:7: Error - ~/test.ini does not have expected permissions of 664
Makefile:7: Error - ~/test.ini does not belong to common group
Makefile:7: Error - ~/test.ini does not belong to netserve user
touch ~/test.ini
chmod -c 664 ~/test.ini
match is broken
match works
chgrp -c fileGroup ~/test.ini
changed group of `/home/myUserName/test.ini' to fileGroup
chown -c fileUser ~/test.ini
chown: changing ownership of `/home/myUserName/test.ini': Operation not permitted
make: [test] Error 1 (ignored)

I've considered/tried the following:

  • $(if ...) is evaluated at "compile-time", before the function is called with a parameter. But, the hard-coded ifeq "foo" "bar" also gives an invalid result. Additionally, $(info ...) correctly evaluates $(fileName) at "compile-time".
  • The documentation doesn't actually give examples, so in addition to $(if ifeq...), I also tried $(ifeq ...), which seemed to be ignored.
  • "Non-functional" if (i.e., the ifeq without the $(if...)) inside a function gives /bin/sh: ifeq: command not found.

Can someone help identify why my conditionals aren't behaving as I expect (or why I'm expecting the wrong thing)?

Caveat: I know there are still bugs to be worked out if the file doesn't exist, but that should be trivial compared to this hurdle.

Solution

  • $(if ...) conditional function evaluates to true when the first argument passed to it is non-empty. In you case the condition is literal text: ifeq "foo" "bar", which is, obviously, non-empty.

    ifeq/ifneq conditionals are in fact directives, not functions. They can't be used inside variable definition and in functions.

    Back to your example, to test string for equality inside the condition use functions like filter and findstring:

    $(if $(filter foo,bar),@echo match is broken,@echo match works)
$(if $(filter-out foo,bar),@echo match works,@echo match is broken)

    BTW this could be also turned into an inline form for better readability:

    @echo match $(if $(filter foo,bar),is broken,works)
@echo match $(if $(filter-out foo,bar),works,is broken)