fix(stacks): allow root based compose file paths (#5506)

api/exec/compose_stack_test.go

@@ -64,3 +64,21 @@ func Test_createEnvFile(t *testing.T) {
 		})
 	}
 }
+
+func Test_getStackFiles(t *testing.T) {
+	stack := &portainer.Stack{
+		EntryPoint: "./file", // picks entry point
+		AdditionalFiles: []string{
+			``,                  // ignores empty string
+			`.`,                 // ignores .
+			`..`,                // ignores ..
+			`./dir/`,            // ignrores paths that end with trailing /
+			`/with-root-prefix`, // replaces "root" based paths with relative
+			`./relative`,        // keeps relative paths
+			`../escape`,         // prevents dir escape
+		},
+	}
+
+	filePaths := getStackFiles(stack)
+	assert.ElementsMatch(t, filePaths, []string{`./file`, `./with-root-prefix`, `./relative`})
+}