fix: only use on-disk file extension for config-matching

internal/core/file.go

@@ -67,28 +67,9 @@ func NewFile(src string, config *Config) (*File, error) {
 		src = "stdin" + config.Flags.InExt
 		lookup = true
 	}
-	filepaths := []string{src}
 
+	filepaths := []string{src}
 	normed := system.ReplaceFileExt(src, config.Formats)
-	if normed != src {
-		// NOTE: In retrospect, this was a mistake: we should NOT normalize
-		// the extension with respect to the `.vale.ini` file.
-		//
-		// The `.vale.ini` file should reflect the actual file extensions (as
-		// they appear on disk). Unfortunately, changing this behavior entirely
-		// would break backwards compatibility with many configurations.
-		//
-		// So, as a workaround, we check both cases. This means that there are
-		// two cases:
-		//
-		// - No assigned format: No change (no normed path).
-		//
-		// - Assigned format: We can reference the file using the normed path
-		// (old behavior) or the actual path (desired behavior).
-		//
-		// See also `Linter.skip`.
-		filepaths = append(filepaths, normed)
-	}
 
 	baseStyles := config.GBaseStyles
 	checks := make(map[string]bool)

testdata/fixtures/formats/subdir3/.vale.ini

@@ -4,5 +4,5 @@ MinAlertLevel = suggestion
 [formats]
 mdx = md
 
-[*.md]
+[*.mdx]
 vale.Annotations = YES

testdata/fixtures/patterns/_vale

@@ -10,8 +10,8 @@ mdx = md
 [*]
 BasedOnStyles = Vale
 
-[*.{md,rst,adoc,org}]
+[*.{md,rst,adoc,org,mdx}]
 TokenIgnores = (\$+?[^\d][^\n$]+\$+?), (<http[^\n]+>+?)
 IgnorePatterns = (?s) *({{< ?file(?:-excerpt)? [^>]* ?>}}.*?{{< ?/file(?:-excerpt)? ?>}})
 
-vale.Redundancy = warning
+vale.Redundancy = warning