linera-io/linera-protocol · error

GITHUB_BASE_BRANCH is not set! This must be run from within

Error message

GITHUB_BASE_BRANCH is not set! This must be run from within CI

What it means

In CI mode, from_env reads GITHUB_BASE_BRANCH — the target branch of the pull request (usually main) — and fails when it is unset. The summary compares PR results against this base, so an unknown base branch makes the run ambiguous and the constructor refuses to continue.

Source

Thrown at linera-summary/src/github.rs:130

            (
                commit_hash,
                branch_name,
                base,
                pr_number.ok_or_else(|| anyhow!("pr_number is None"))?,
            )
        } else {
            let pr_string = env_pr_number.map_err(|_| {
                anyhow!("GITHUB_PR_NUMBER is not set! This must be run from within CI")
            })?;
            (
                env_pr_commit_hash.map_err(|_| {
                    anyhow!("GITHUB_PR_COMMIT_HASH is not set! This must be run from within CI")
                })?,
                env_pr_branch.map_err(|_| {
                    anyhow!("GITHUB_PR_BRANCH is not set! This must be run from within CI")
                })?,
                env_base_branch.map_err(|_| {
                    anyhow!("GITHUB_BASE_BRANCH is not set! This must be run from within CI")
                })?,
                pr_string
                    .parse()
                    .map_err(|_| anyhow!("GITHUB_PR_NUMBER is not a valid number: {pr_string}"))?,
            )
        };

        Ok(Self {
            repository: GithubRepository::from_env(is_local)?,
            pr_commit_hash,
            pr_branch,
            base_branch,
            pr_number,
        })
    }
}

/// A GitHub client bound to a PR context, used to query workflow runs/jobs and post comments.

View on GitHub (pinned to 6c226ddcb3)

Solutions

  1. Export the base branch in the workflow: GITHUB_BASE_BRANCH: ${{ github.base_ref }}
  2. Or set it manually with the other three GITHUB_PR_*/BASE variables when running outside Actions
  3. Grep the workflow env block for typos — the other three sibling variables fail with their own messages, so fix all that appear

Example fix

# before
env:
  GITHUB_BASE: ${{ github.base_ref }}
# after
env:
  GITHUB_BASE_BRANCH: ${{ github.base_ref }}
Defensive patterns

Strategy: validation

Validate before calling

#!/usr/bin/env bash
: "${GITHUB_BASE_BRANCH:?GITHUB_BASE_BRANCH is required (PR target branch)}"

Try / catch

if let Err(e) = Github::new(false, None) {
    if e.to_string().contains("GITHUB_BASE_BRANCH") {
        eprintln!("export GITHUB_BASE_BRANCH=${{ github.base_ref }} in the workflow env");
    }
    return Err(e.into());
}

Prevention

When it happens

Trigger: Running the tool in CI mode without GITHUB_BASE_BRANCH exported; workflows that map github.base_ref to a differently-named variable; local emulation missing one of the four required variables.

Common situations: Incomplete hand-maintained workflow env blocks; running the summary step in a reusable workflow that did not forward the variables; CI environments that strip GITHUB_-prefixed vars for security.

Understand the failure class

Background: "environment variable is not set" and "Missing keys in environment" errors: what missing required env var messages mean and how to fix them — this error's family across 28 libraries.

Related errors

AI-assisted analysis of linera-io/linera-protocol@6c226ddcb3 (2026-08-22). Data as JSON: /api/errors/70d31864c106ebda. Report an issue: GitHub.