Add input.json to inputs.json fallback when file is missing

Author: mmaelicke

internal/io/read.go

@@ -3,6 +3,7 @@ package io
 import (
 	"fmt"
 	"os"
+	"path/filepath"
 
 	"github.com/alexander-lindner/go-cff"
 	toolspec "github.com/hydrocode-de/tool-spec-go"
@@ -25,6 +26,18 @@ func ReadSpecFile(path string) (toolspec.SpecFile, error) {
 func ReadInputFile(path string) (toolspec.InputFile, error) {
 	inputBuffer, err := os.ReadFile(path)
 	if err != nil {
+		// Backward-compatible fallback for tools that still mount /in/inputs.json.
+		if os.IsNotExist(err) && filepath.Base(path) == "input.json" {
+			fallbackPath := filepath.Join(filepath.Dir(path), "inputs.json")
+			fallbackBuffer, fallbackErr := os.ReadFile(fallbackPath)
+			if fallbackErr == nil {
+				input, parseErr := toolspec.LoadInputs(fallbackBuffer)
+				if parseErr != nil {
+					return toolspec.InputFile{}, fmt.Errorf("failed to load input file: %w", parseErr)
+				}
+				return input, nil
+			}
+		}
 		return toolspec.InputFile{}, fmt.Errorf("failed to read input file: %w", err)
 	}
 

internal/io/read_test.go

@@ -0,0 +1,46 @@
+package io
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+const testInputJSON = `{
+  "demo": {
+    "parameters": {},
+    "data": {}
+  }
+}`
+
+func TestReadInputFileFallsBackToInputsJSON(t *testing.T) {
+	dir := t.TempDir()
+	fallbackPath := filepath.Join(dir, "inputs.json")
+
+	if err := os.WriteFile(fallbackPath, []byte(testInputJSON), 0o644); err != nil {
+		t.Fatalf("failed to write fallback inputs.json: %v", err)
+	}
+
+	_, err := ReadInputFile(filepath.Join(dir, "input.json"))
+	if err != nil {
+		t.Fatalf("expected fallback from input.json to inputs.json, got error: %v", err)
+	}
+}
+
+func TestReadInputFilePrefersInputJSONWhenPresent(t *testing.T) {
+	dir := t.TempDir()
+	inputPath := filepath.Join(dir, "input.json")
+	fallbackPath := filepath.Join(dir, "inputs.json")
+
+	if err := os.WriteFile(inputPath, []byte(testInputJSON), 0o644); err != nil {
+		t.Fatalf("failed to write input.json: %v", err)
+	}
+	if err := os.WriteFile(fallbackPath, []byte("not-json"), 0o644); err != nil {
+		t.Fatalf("failed to write inputs.json: %v", err)
+	}
+
+	_, err := ReadInputFile(inputPath)
+	if err != nil {
+		t.Fatalf("expected input.json to be used first, got error: %v", err)
+	}
+}