fix: check if pyproject has poetry earlier

During the evaluation in the package phase, we determine whether a
`requirements.txt` file exists, or whether we need to generate one.

Since the `pyproject.toml` file is used by poetry, but only if a stanza
is contained inside the file, use the function `isPoetryProject()` along
with the configuration value, thereby reducing the need for a project to
have to declare a configuration override.

Refs serverless#324
Refs serverless#344
Fixes serverless#400

Signed-off-by: Mike Fiedler <[email protected]>

Author: miketheman

lib/pip.js

@@ -63,8 +63,9 @@ function generateRequirementsFile(
 ) {
   if (
     options.usePoetry &&
-    fse.existsSync(path.join(servicePath, 'pyproject.toml')) &&
-    isPoetryProject(servicePath)
+    fse.existsSync(
+      path.join(servicePath, 'pyproject.toml') && isPoetryProject(servicePath)
+    )
   ) {
     filterRequirementsFile(
       path.join(servicePath, '.serverless/requirements.txt'),