Refactor parsers and support pyproject-only projects (#8)

Refactor the parsers functions into classes, simplify the logic of parsers and
add support for projects that only have a pyproject.toml file.

dependente/cli.py

@@ -8,16 +8,12 @@
 """
 import sys
 import traceback
+from pathlib import Path
 
 import click
 
 from .converters import pin_to_oldest
-from .parsers import (
- parse_requirements,
- parse_sources,
- read_pyproject_toml,
- read_setup_cfg,
-)
+from .parsers import get_parser, validate_sources
 
 
 @click.command(context_settings={"help_option_names": ["-h", "--help"]})
@@ -54,28 +50,30 @@ def main(source, oldest, verbose):
 
  Supported formats:
 
- * pyproject.toml (only build-system > requires)
+ * pyproject.toml (build-system > requires, project > dependencies and
+ project.optional-dependencies)
 
  * setup.cfg (install_requires and options.extras_require)
 
  """
  reporter = Reporter(verbose)
- readers = {"setup.cfg": read_setup_cfg, "pyproject.toml": read_pyproject_toml}
- reporter.echo(f"Extracting dependencies: {source}")
+ sources = source.split(",")
+ validate_sources(sources)
  try:
- sources = parse_sources(source)
+ config_files = get_sources_and_config_files(sources)
+ # Parse dependencies
  dependencies = []
- for config_file in sources:
- if not sources[config_file]:
- continue
+ for config_file, sources in config_files.items():
  reporter.echo(f"Parsing {config_file}")
- config = readers[config_file]()
- dependencies_found = parse_requirements(config, sources[config_file])
+ parser = get_parser(config_file)
+ dependencies_found = parser.parse_requirements(sources)
  reporter.echo(f" - {count(dependencies_found)} dependencies found")
  dependencies.extend(dependencies_found)
+ # Pin to oldest versions
  if oldest:
  reporter.echo("Pinning dependencies to their oldest versions")
  dependencies = pin_to_oldest(dependencies)
+ # Print gathered dependencies to stdout
  reporter.echo(
  f"Printing {count(dependencies)} dependencies to standard output",
  )
@@ -89,6 +87,55 @@ def main(source, oldest, verbose):
  sys.exit(1)
 
 
+def get_sources_and_config_files(sources):
+ """
+ Get configuration files in working directory and corresponding sources
+
+ Find configuration files in current directory and sort out which sources
+ should be parsed from which config file.
+
+ Parameters
+ ----------
+ sources : list of str
+ List containing a subset of valid sources ("build", "install",
+ "extras").
+
+ Returns
+ -------
+ config_files : dict
+ Dictionary with config files as keys. Their values are a list of
+ sources that should be parsed from each one of them.
+
+ Raises
+ ------
+ FileNotFoundError
+ If both ``setup.cfg`` and ``pyproject.toml`` are missing in the current
+ directory.
+ If "build" is in ``sources``, but ``pyproject.toml`` is not present in
+ the current directory.
+ """
+ # Get configuration files in working directory
+ fnames = ("pyproject.toml", "setup.cfg")
+ config_fnames = [fname for fname in fnames if Path(fname).is_file()]
+ if not config_fnames:
+ raise FileNotFoundError("Missing 'pyproject.toml' and 'setup.cfg' files.")
+ # Sort out sources
+ if "build" in sources and "pyproject.toml" not in config_fnames:
+ raise FileNotFoundError(
+ "Missing 'pyproject.toml' file while asking for 'build' sources. "
+ "The 'build' sources can only be parsed from a 'pyproject.toml' file."
+ )
+ if "setup.cfg" in config_fnames:
+ config_files = {
+ "pyproject.toml": ["build"] if "build" in sources else [],
+ "setup.cfg": [s for s in sources if s != "build"],
+ }
+ else:
+ config_files = {"pyproject.toml": sources}
+ config_files = {key: value for key, value in config_files.items() if value}
+ return config_files
+
+
 def count(dependencies):
  """
  Count the number of dependencies in a list.