feat(gas-oracle): make L1 base/blob fee caps configurable via env

[curryxbo]

What

The upper caps applied to the fetched L1 base fee and blob base fee in gas-oracle were hardcoded:

const MAX_BASE_FEE: u128 = 1000 * 10i32.pow(9) as u128;      // 1000 Gwei
const MAX_BLOB_BASE_FEE: u128 = 100 * 10i32.pow(9) as u128;  // 100 Gwei

During sustained L1 fee spikes these caps silently clamp the value pushed on-chain, and there is no way to tune them without a rebuild/redeploy.

Change

• Move both caps into Config, read from env GAS_ORACLE_MAX_L1_BASE_FEE / GAS_ORACLE_MAX_L1_BLOB_BASE_FEE.
• Defaults equal the previous constants (1000 Gwei / 100 Gwei), so behavior is unchanged unless explicitly overridden.
• Thread the two values through BaseFeeUpdater::new, mirroring the existing gas_threshold / *_buffer config pattern.

Two files, no public API change beyond the internal constructor (its only caller is updated).

Context

Surfaced by morph-l2/morph-ideas idea #5 (hardcoded fee-cap tech debt): https://github.com/morph-l2/morph-ideas/blob/main/idea-005.html

🤖 Generated with Claude Code

Summary by CodeRabbit

• New Features

  • Added configurable maximum limits for L1 base fees and L1 blob fees.
  • Operators can set these limits through environment variables, with safe defaults when values are not provided.

• Bug Fixes

  • L1 fee calculations are now capped according to the configured limits, helping prevent unexpectedly high fee values.

[claude]

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ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 58a66e3c-d1ad-4828-868c-db5a7bdf345e

📥 Commits

Reviewing files that changed from the base of the PR and between 21d05b9 and 276c676.

📒 Files selected for processing (2)

• gas-oracle/app/src/gas_price_oracle.rs
• gas-oracle/app/src/l1_base_fee.rs

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📝 Walkthrough

Walkthrough

The gas price oracle now reads configurable L1 base fee and blob base fee caps from environment variables, passes them to BaseFeeUpdater, and uses them when clamping computed fees.

Changes

Configurable L1 fee caps

Layer / File(s)	Summary
Configurable updater clamping gas-oracle/app/src/l1_base_fee.rs	BaseFeeUpdater stores configurable fee maxima and uses them instead of fixed constants during fee clamping.
Oracle configuration wiring gas-oracle/app/src/gas_price_oracle.rs	Configuration loads the two fee caps from environment variables with defaults and passes them to BaseFeeUpdater.

Estimated code review effort: 2 (Simple) | ~10 minutes

Sequence Diagram(s)

sequenceDiagram
  participant Environment
  participant Config
  participant prepare_updater
  participant BaseFeeUpdater
  Environment->>Config: Provide L1 fee cap values
  Config->>prepare_updater: Expose configured caps
  prepare_updater->>BaseFeeUpdater: Pass cap parameters
  BaseFeeUpdater->>BaseFeeUpdater: Clamp computed fees

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Suggested reviewers: securitylife

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: making L1 base and blob fee caps configurable through environment variables.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/gas-oracle-configurable-fee-caps

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