[bug] AutotoolsToolchain does not respect extra_cflags or extra_cxxflags when used with environment vars.

[planetmarshall]

AutotoolsToolchain does not respect the extra_cflags attribute when used with the environment.

Environment Details (include every applicable attribute)

• Operating System+version: Ubuntu 22.04
• Compiler+version: clang 14
• Conan version: 1.52
• Python version: 3.10

Steps to reproduce

conan new at/1.0.0 -t -m autotools_lib

Edit the conanfile generate method to add

def generate(self):
  ...  
  env = at_toolchain.environment()
  at_toolchain.extra_cxxflags.append("-march=native")
  at_toolchain.generate(env)
  ...

Run

$ conan create . > log.txt
$ grep march log.txt

Expected result

The -march=native flag should be present in the compiler command line:

/bin/bash ../libtool  --tag=CXX   --mode=link clang++  -stdlib=libc++ -m64 -fPIC -O3 -march=native  -m64 -o libat.la -rpath //lib at.lo

Actual result

The additional flag is not preset

/bin/bash ../libtool  --tag=CXX   --mode=link clang++  -stdlib=libc++ -m64 -fPIC -O3  -m64 -o libat.la -rpath //lib at.lo

Workaround

Use

def generate(self):
  at_toolchain = AutotoolsToolchain(self)
  env = at_toolchain.environment()
  env.define("CXXFLAGS", at_toolchain.cxxflags + ["-march=native"])
  at_toolchain.generate(env)

The flag is present in the output as expected.

[memsharded]

Hi @planetmarshall

I was checking the unit tests and they seem to cover this functionality.
I also tried manually, and seems to be working fine, I added a random flag and got:

cl : Command line warning D9002 : ignoring unknown option '-someflags'

Apparently it is working fine, could you please re-check?

[planetmarshall]

Hi @planetmarshall

Apparently it is working fine, could you please re-check?

If you only use the extra_cflags functionality, it works. If you also use the environment, it doesn't. For example:

def generate(self):
  tc = AutotoolsToolchain(self)
  tc.cflags.append("-someflags")
  tc.generate()

Adds the flag - whereas:

def generate(self):
  tc = AutotoolsToolchain(self)
  env = tc.environment()
  tc.cflags.append("-someflags")
  tc.generate(env)

Does not.

See conan-io/conan-center-index#13263 for a full example

[jcar87]

Hi @planetmarshall - thank you for reporting this.

I believe this is caused by "capturing" the state of the environment (env = tc.environment()) before manipulating the extra flags, and then passing that variable to tc.generate() - which will in essence override with the values in env instead.

Does it work if you swap the order around?, e.g.:

def generate(self):
  tc = AutotoolsToolchain(self)
  tc.extra_cxxflags.append("-march=native")
  env = tc.environment()
  tc.generate(env)

[planetmarshall]

Hi @planetmarshall - thank you for reporting this.

Does it work if you swap the order around?, e.g.:

Yes this works, thanks.