#164: Add POETRY_DYNAMIC_VERSIONING_DEBUG env var

CHANGELOG.md

@@ -4,6 +4,7 @@
   * `pattern-prefix` option to add a prefix to the version tag pattern.
   * `ignore-untracked` option to control the detection of dirty state.
   * `from-file` config section to read a version from a file instead of the VCS.
+  * `POETRY_DYNAMIC_VERSIONING_DEBUG` environment variable for some logging.
 * Changed:
   * Updated Dunamai to 1.21.0+ for the latest features.
 

README.md

@@ -358,6 +358,9 @@ you can apply some global overrides via environment variables.
   Comma-separated list of Poetry commands during which the plugin should **not** directly modify files.
   The plugin will still set the dynamic version in memory so that Poetry itself can write it as needed.
   Default: `version`.
+* `POETRY_DYNAMIC_VERSIONING_DEBUG`:
+  If this is set to `1`, then some debug logs will be printed to stderr.
+  Right now, this logs some cases where substitution doesn't find anything to change.
 
 ## Command line mode
 The plugin also has a command line mode for execution on demand.

poetry_dynamic_versioning/__init__.py

@@ -29,6 +29,7 @@
 
 _BYPASS_ENV = "POETRY_DYNAMIC_VERSIONING_BYPASS"
 _OVERRIDE_ENV = "POETRY_DYNAMIC_VERSIONING_OVERRIDE"
+_DEBUG_ENV = "POETRY_DYNAMIC_VERSIONING_DEBUG"
 
 if sys.version_info >= (3, 8):
     from typing import TypedDict
@@ -239,6 +240,13 @@ def _deep_merge_dicts(base: Mapping, addition: Mapping) -> Mapping:
     return result
 
 
+def _debug(message: str) -> None:
+    enabled = os.environ.get(_DEBUG_ENV) == "1"
+
+    if enabled:
+        print(message, file=sys.stderr)
+
+
 def _find_higher_file(*names: str, start: Optional[Path] = None) -> Optional[Path]:
     # Note: We need to make sure we get a pathlib object. Many tox poetry
     # helpers will pass us a string and not a pathlib object. See issue #40.
@@ -524,19 +532,31 @@ def _substitute_version(name: str, version: str, folders: Sequence[_FolderConfig
     files = {}  # type: MutableMapping[Path, _FolderConfig]
     for folder in folders:
         for file_glob in folder.files:
+            i = 0
+
             # call str() since file_glob here could be a non-internable string
             for match in folder.path.glob(str(file_glob)):
+                i += 1
                 resolved = match.resolve()
                 if resolved in files:
                     continue
                 files[resolved] = folder
 
+            if i == 0:
+                _debug(
+                    "No files found for substitution with glob '{}' in folder '{}'".format(
+                        file_glob, folder.path
+                    )
+                )
+
     for file, config in files.items():
         original_content = file.read_bytes().decode("utf-8")
         new_content = _substitute_version_in_text(version, original_content, config.patterns)
         if original_content != new_content:
             _state.projects[name].substitutions[file] = original_content
             file.write_bytes(new_content.encode("utf-8"))
+        else:
+            _debug("No changes made during substitution in file '{}'".format(file))
 
 
 def _substitute_version_in_text(version: str, content: str, patterns: Sequence[_SubPattern]) -> str: