Add disallowLegacyRuntimeConfig property to skip Runtime Config API during function deploys. #9354

taeold · 2025-10-21T01:41:42Z

Adds per-codebase firebase.json property disallowLegacyRuntimeConfig to prevent fetching and using legacy Runtime Config (functions.config()) during deployment. Defaults to false for backward compatibility.

Example firebase.json:

    {
      "functions": {
        "source": "functions",
        "codebase": "default",
        "disallowLegacyRuntimeConfig": true // NEW
      }
    }

New functions codebase initialized using firebase init function will have this property set to true. This shouldn't be disruptive since template code uses the v2 API which doesn't allow use of functions.config() API anyway.

When using --only functions:SELECTOR, resolve ambiguous selectors by checking if SELECTOR matches a known codebase name: - If yes: target only that codebase - If no: treat as function ID in default codebase This prevents unnecessary codebase scanning and runtime config fetches for non-targeted codebases. Example: With codebases 'default' and 'other': firebase deploy --only functions:other Before: scans both 'other' codebase AND 'default' for 'other-*' functions After: scans only 'other' codebase

gemini-code-assist · 2025-10-21T01:42:03Z

Summary of Changes

Hello @taeold, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request enhances the Firebase Functions deployment process by introducing a new "disallowLegacyRuntimeConfig" property in firebase.json. This property empowers developers to explicitly prevent the fetching and use of the deprecated functions.config() API during deployment for specific function codebases. This change facilitates a smoother transition away from legacy runtime configuration, especially for new projects where this property will be enabled by default. It also streamlines the internal logic by replacing a global experiment flag with a more granular, codebase-specific configuration option.

Highlights

New Configuration Property: Introduced "disallowLegacyRuntimeConfig" in firebase.json for Firebase Functions, allowing per-codebase control over the use of the deprecated functions.config() API during deployment.
Default Behavior for New Codebases: New function codebases initialized with "firebase init function" will have "disallowLegacyRuntimeConfig" set to true by default, promoting the use of modern configuration methods.
Removal of Experiment Flag: The "dangerouslyAllowFunctionsConfig" experiment flag has been removed, with its functionality now managed by the new codebase-specific configuration property.
Conditional Runtime Config Loading: The deployment process now conditionally fetches and passes legacy runtime configuration only to codebases that explicitly allow it (i.e., "disallowLegacyRuntimeConfig" is not true), improving efficiency and clarity.

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gemini-code-assist

Code Review

This pull request introduces the disallowLegacyRuntimeConfig property to give users control over using legacy Runtime Config on a per-codebase basis. The implementation is solid, with the old experiment flag being correctly removed and replaced by the new configuration. The changes are consistent across the codebase, and I appreciate the addition of comprehensive unit tests for the new logic.

My review includes a few suggestions to improve code maintainability and performance, mainly by refactoring repetitive test code and optimizing a loop. Overall, this is a great change that improves the configuration flexibility for Firebase Functions.

src/deploy/functions/prepare.ts

src/deploy/functions/prepare.spec.ts

src/functions/projectConfig.spec.ts

* feat: Add isAvailable function for dynamic tool availability This change introduces a new system for determining tool availability in the MCP server. Each tool now has an `isAvailable` function that returns a boolean, and this function is invoked whenever the available tools are checked. - Added an optional `isAvailable` async function to the `ServerTool` interface and the `tool` factory function. - Refactored `availableTools` to be asynchronous, filtering tools based on the result of their `isAvailable` function. - Updated `FirebaseMcpServer` and all relevant call sites to handle asynchronous tool loading. - Implemented the `isAvailable` function for all tools. - Most tools use the `checkFeatureActive` utility to check for both `firebase.json` configuration and API enablement. - Core tools, like `list_projects` and `get_project`, always return `true`. This addresses the feedback from previous code reviews and ensures a consistent and complete implementation of the dynamic tool availability feature. * Create default availability functions and caching on api availability * Respond to code review comments --------- Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com> Co-authored-by: Cleo Schneider <[email protected]> Co-authored-by: Visu <[email protected]>

…uring function deploys. Adds per-codebase firebase.json property 'disallowLegacyRuntimeConfig' to prevent fetching and using legacy Runtime Config (functions.config()) during deployment. Defaults to false for backward compatibility. Example firebase.json: { "functions": { "source": "functions", "codebase": "default", "disallowLegacyRuntimeConfig": true } }

taeold · 2025-10-21T20:55:00Z

/gemini review

gemini-code-assist

Code Review

This pull request introduces a disallowLegacyRuntimeConfig property to firebase.json, allowing developers to opt-out of fetching legacy functions.config() values. This is a solid step towards deprecating the old runtime config API. The changes are well-implemented across the configuration schema, deployment logic, and initialization templates, and are supported by a good set of tests. I have one suggestion to improve the type definitions for a cleaner configuration schema. Overall, this is a great enhancement.

src/firebaseConfig.ts

jhuleatt · 2025-10-21T21:03:03Z

src/deploy/functions/prepare.ts

    );
-    const discoveredBuild = await runtimeDelegate.discoverBuild(runtimeConfig, {
+
+    const codebaseRuntimeConfig = shouldUseRuntimeConfig(codebaseConfig)


worth logging here? maybe if true, log a warning that runtime config is going away? tempting to log if false, but that would probably get too noisy and might confuse.

Will functions.config() just silently fail if someone on v6 has runtime config turned off in their firebase.json but tries to use it in their functions code? the env var the firebase-functions SDK reads for functions.config will just be undefined, right?

yes it would be equivalent to functions.config() returning an empty object

…irebase/firebase-tools into disallow-legacy-runtime-config

github-project-automation bot added this to [Cloud] Extensions + Functions Oct 21, 2025

gemini-code-assist bot reviewed Oct 21, 2025

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Base automatically changed from filter-smart-codebase-resolution to master October 21, 2025 17:09

samedson and others added 8 commits October 21, 2025 10:54

Fix cleaning up clean directory for clean-install.sh (#9347)

dfdd7c5

Remove options.interactive and improve typing.

ef634fc

Add eval runner for Gemini CLI + Firebase CLI (#9333)

cb9ca43

update vscode to 1.10.0 (#9348)

ca7a847

add changelog

a53dada

respond to comments

224673e

taeold force-pushed the disallow-legacy-runtime-config branch from 7c57c5f to 224673e Compare October 21, 2025 17:54

taeold added 3 commits October 21, 2025 10:59

Merge branch 'master' into disallow-legacy-runtime-config

d7e68f0

nits

ce85748

fix tests.

7f7cb25

taeold requested review from brittanycho and jhuleatt October 21, 2025 20:29

add changelog.

6ce746f

gemini-code-assist bot reviewed Oct 21, 2025

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jhuleatt approved these changes Oct 21, 2025

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github-project-automation bot moved this to Approved [PR] in [Cloud] Extensions + Functions Oct 21, 2025

jhuleatt approved these changes Oct 21, 2025

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taeold added 5 commits October 21, 2025 14:44

comment

2f3758e

Merge branch 'master' into disallow-legacy-runtime-config

8229b08

fix types

75f8cd3

Merge branch 'disallow-legacy-runtime-config' of https://github.com/f…

de50d69

…irebase/firebase-tools into disallow-legacy-runtime-config

Merge branch 'master' into disallow-legacy-runtime-config

74280d4

taeold merged commit dde651b into master Oct 21, 2025
48 checks passed

taeold deleted the disallow-legacy-runtime-config branch October 21, 2025 22:31

github-project-automation bot moved this from Approved [PR] to Done in [Cloud] Extensions + Functions Oct 21, 2025

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Add disallowLegacyRuntimeConfig property to skip Runtime Config API during function deploys. #9354

Add disallowLegacyRuntimeConfig property to skip Runtime Config API during function deploys. #9354

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Add disallowLegacyRuntimeConfig property to skip Runtime Config API during function deploys. #9354

Add disallowLegacyRuntimeConfig property to skip Runtime Config API during function deploys. #9354

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