[bug] Conan build command does not support conanfile.txt as described

[uilianries]

Description

The documentation about build command says:

usage: conan build [-h] [-v [V]] [--logger] [--name NAME] [--version VERSION] [--user USER] [--channel CHANNEL] [-of OUTPUT_FOLDER] [-b BUILD] [-r REMOTE | -nr] [-u] [-o OPTIONS_HOST] [-o:b OPTIONS_BUILD] [-o:h OPTIONS_HOST] [-pr PROFILE_HOST] [-pr:b PROFILE_BUILD]
                   [-pr:h PROFILE_HOST] [-s SETTINGS_HOST] [-s:b SETTINGS_BUILD] [-s:h SETTINGS_HOST] [-c CONF_HOST] [-c:b CONF_BUILD] [-c:h CONF_HOST] [-l LOCKFILE] [--lockfile-partial] [--lockfile-out LOCKFILE_OUT] [--lockfile-packages] [--lockfile-clean]
                   [path]

Install dependencies and call the build() method.

positional arguments:
  path                  Path to a folder containing a recipe (conanfile.py or conanfile.txt) or to a recipe file. e.g., ./my_project/conanfile.txt.

However, conanfile.txt is not acceptable by build command.

As the documentation is extracted from the command output, it should be fixed on Conan client first.

Environment details

• Operating System+version: OSX 13
• Compiler+version: Apple-Clang 14
• Conan version: 2.0.0
• Python version: 3.10

Steps to reproduce

1. mkdir /tmp/foo && cd /tmp/foo
2. echo "[requires]\nzlib/1.2.13" > conanfile.txt
3. conan build .
4. Or, conan build ./conanfile.txt

Logs

% conan build .
ERROR: Conanfile not found at /private/tmp/foo/conanfile.py

% conan build ./conanfile.txt   
ERROR: A conanfile.py is needed, /private/tmp/conantxt/conanfile.txt is not acceptable

[AbrilRBS]

Anyone wanting to take a stab at this, I'll give some pointers:

• Conan commands live under conan/cli/commands
• Conan uses argparse for its CLI interaction
• The solution for this one is easy: we do require it to be a .py file, so the help text suggesting that .txt files in the command are valid is wrong, and should be changed, but as I'm not an enligh native speaker, I'll let you choose the best wording :)
• If the PR you open has failing tests, do not worry! Some tests might rely on CLI output, we can fix those after the fact

[kammce]

I can take a stab at it 😄

[memsharded]

Amazing! thanks for the offer @kammce !