GitHub Actions "Unexpected symbol" in a ${{ }} expression
The expression parser hit a character it does not understand inside a ${{ }} block, usually a bad operator or an unquoted literal.
What this error means
The workflow is rejected with "Unexpected symbol" and the position within the expression.
The workflow is not valid. .github/workflows/ci.yml (Line: 9): Unexpected symbol: '"prod'. Located at position 12 within expression: github.ref == "prodDiagnose it: print the context before you change anything
Most workflow-expression bugs are not syntax errors, they are an expression reading something that is empty. GitHub resolves a missing property to an empty string instead of failing the run, so a wrong reference looks like a logic bug rather than a mistake. Dump the contexts first and you will usually see the answer immediately.
- name: Dump contexts
run: |
echo '--- github ---' ; echo '${{ toJSON(github) }}'
echo '--- needs ---' ; echo '${{ toJSON(needs) }}'
echo '--- steps ---' ; echo '${{ toJSON(steps) }}'
echo '--- matrix ---' ; echo '${{ toJSON(matrix) }}'
echo '--- inputs ---' ; echo '${{ toJSON(inputs) }}'Check the context is allowed where you used it
Contexts are not available everywhere. The same expression can be valid in a step if and invalid in a job if, which is why an expression that works in one workflow fails when moved.
| Where you wrote it | Contexts available there |
|---|---|
run-name | github, inputs, vars |
concurrency | github, inputs, vars |
Top-level env | github, secrets, inputs, vars |
jobs.<id>.if | github, needs, vars, inputs |
jobs.<id>.steps.if | github, needs, strategy, matrix, job, runner, env, vars, steps, inputs |
jobs.<id>.outputs | Full access, including secrets |
Reusable workflow outputs | github, jobs, vars, inputs |
Common causes
Unterminated or unquoted string
String literals inside expressions use single quotes; a missing closing quote or double quotes inside YAML can break parsing.
Unsupported operator
Operators like += or & are not valid; expressions support ==, !=, &&, ||, !, and comparisons.
How to fix it
Use single-quoted literals and valid operators
- Wrap string literals in single quotes inside expressions.
- Use && and || for logic, not & or |.
if: ${{ github.ref == 'refs/heads/main' && github.event_name == 'push' }}Catch it before it reaches CI
Every failure in this cluster is statically detectable. actionlint parses workflow expressions, checks context availability against the same rules above, and validates needs references, so these bugs never need to cost you a run.
# one-off
docker run --rm -v "$(pwd):/repo" --workdir /repo rhysd/actionlint:latest -color
# as a job, before anything expensive runs
- uses: actions/checkout@v4
- run: |
bash <(curl -s https://raw.githubusercontent.com/rhysd/actionlint/main/scripts/download-actionlint.bash)
./actionlint -colorHow to prevent it
- Keep expressions simple; move complex logic to a run step.
- Run actionlint to validate expression syntax.