facebook/relay · error

Failed to run locate command: {}

Error message

Failed to run locate command: {}

What it means

resolve_field_definition spawns the configured locate_command with project_name and entity_name as arguments. If the process cannot be spawned or awaited (binary missing, not executable, IO error), the error is wrapped with this 'Failed to run locate command: {}' message and returned as a string error.

Source

Thrown at compiler/crates/relay-bin/src/main.rs:625

    }

    fn resolve_field_definition(
        &self,
        project_name: String,
        parent_type: String,
        field_info: Option<FieldSchemaInfo>,
    ) -> Result<Option<FieldDefinitionSourceInfo>, String> {
        let entity_name = match field_info {
            Some(field_info) => format!("{}.{}", parent_type, field_info.name),
            None => parent_type,
        };
        let result = Command::new(&self.locate_command)
            .arg(project_name)
            .arg(entity_name)
            .output()
            .map_err(|e| format!("Failed to run locate command: {}", e))?;

        let result = String::from_utf8(result.stdout).expect("Failed to parse output");

        // Parse file_path:line_number:column_number
        let result_trimmed = result.trim();
        let result = result_trimmed.split(':').collect::<Vec<_>>();
        if result.len() != 3 {
            return Err(format!(
                "Result '{}' did not match expected format. Please return 'file_path:line_number:column_number'",
                result_trimmed
            ));
        }
        let file_path = result[0];
        let line_number = result[1].parse::<u64>().unwrap() - 1;
        let column_number = result[2].parse::<u64>().unwrap_or(1_u64) - 1;

        Ok(Some(FieldDefinitionSourceInfo {
            file_path: file_path.to_string(),
            line_number,
            column_number,

View on GitHub (pinned to 668b1b85e0)

Solutions

1. Verify the locate command exists and runs: run it manually with the same two arguments
2. Make the script executable (chmod +x) and give it a proper shebang
3. Use an absolute path for the command in the relay config
4. Check PATH in the environment that launches relay (IDE-integrated terminals often differ)

Example fix

// before (relay config)
"locateCommand": "scripts/find-field"
// after (absolute, executable)
"locateCommand": "/absolute/path/to/scripts/find-field"  # + chmod +x

const { execFileSync } = require('child_process');
function assertLocateRunnable(cmd, ...args) {
  try { execFileSync(cmd, args, { stdio: 'ignore' }); }
  catch (e) {
    if (e.code === 'ENOENT') throw new Error(`Locate command not found: ${cmd}`);
  }
}

try {
  resolveFieldDefinition(project, entity);
} catch (e) {
  if (/Failed to run locate command/.test(e.message)) {
    console.error('Ensure the locate binary exists, is executable, and is on PATH.');
  } else throw e;
}

When it happens

Trigger: Calling the field-resolution feature when locate_command points to a non-existent binary, lacks execute permission, or the OS refuses to fork/exec.

Common situations: Configured locate tool not installed on the machine; script path relative to a different working directory; missing shebang or +x bit; PATH differences in editors/IDEs launching relay.

Related errors

• failed to execute process. Make sure you have Node installed
• Result '{}' did not match expected format. Please return 'fi
• Platform "${process.platform} (${process.arch})" not support
• Relay Environment Configuration Error (dev only): `@required
• No Relay config found from current directory. Pass --config

AI-assisted analysis of facebook/relay@668b1b85e0 (2026-09-02). Data as JSON: /api/errors/145f879aa72bc146. Report an issue: GitHub.