Only convert absolute path to relative, otherwise use relativepath in source bundle parser

internal/configs/source_bundle_parser.go

@@ -68,28 +68,35 @@ func (p *SourceBundleParser) LoadConfigDir(source sourceaddrs.FinalSource) (*Mod
 		return nil, diags
 	}
 
-	// The result of sources.LocalPathForSource is an absolute path, but we
+	// The result of sources.LocalPathForSource can be an absolute path, but we
 	// don't actually want to pass an absolute path for a module's SourceDir;
 	// doing so will cause the value of `path.module` in Terraform configs to
 	// differ across plans and applies, since tfc-agent performs plans and
 	// applies in temporary directories. Instead, we try to resolve a relative
 	// path from Terraform's working directory, which should always be a
 	// reasonable SourceDir value.
-	workDir, err := os.Getwd()
-	if err != nil {
-		diags = diags.Append(&hcl.Diagnostic{
-			Severity: hcl.DiagError,
-			Summary:  "Cannot resolve working directory",
-			Detail:   fmt.Sprintf("Failed to resolve current working directory: %s. This is a bug in Terraform - please report it.", err),
-		})
-	}
-	relativeSourceDir, err := filepath.Rel(workDir, sourceDir)
-	if err != nil {
-		diags = diags.Append(&hcl.Diagnostic{
-			Severity: hcl.DiagError,
-			Summary:  "Cannot resolve relative path",
-			Detail:   fmt.Sprintf("Failed to resolve relative path to module directory: %s. This is a bug in Terraform - please report it.", err),
-		})
+	var relativeSourceDir string
+	if filepath.IsAbs(sourceDir) {
+		workDir, err := os.Getwd()
+		if err != nil {
+			diags = diags.Append(&hcl.Diagnostic{
+				Severity: hcl.DiagError,
+				Summary:  "Cannot resolve working directory",
+				Detail:   fmt.Sprintf("Failed to resolve current working directory: %s. This is a bug in Terraform - please report it.", err),
+			})
+		}
+
+		relativeSourceDir, err = filepath.Rel(workDir, sourceDir)
+		if err != nil {
+			diags = diags.Append(&hcl.Diagnostic{
+				Severity: hcl.DiagError,
+				Summary:  "Cannot resolve relative path",
+				Detail:   fmt.Sprintf("Failed to resolve relative path to module directory: %s. This is a bug in Terraform - please report it.", err),
+			})
+		}
+	} else {
+		// sourceDir is already relative, use it as-is
+		relativeSourceDir = sourceDir
 	}
 	mod.SourceDir = relativeSourceDir