fix(platform): preserve explicit local dryRun

[zeitlinger]

Changes

When the local platform initializer is called with an explicit dryRun value, preserve it instead of always overwriting with lookup. Only extract is preserved — anything else (including full, which would error against the local platform) falls back to lookup.

Context

• This doesn't close an Issue, but I accept the risk that this PR may be closed if maintainers disagree with its opening or implementation

AI assistance disclosure

• Yes — substantive assistance (AI-generated non‑trivial portions of code, tests, or documentation).

Used Claude Code for the initial diagnosis, code change, and test additions.

Documentation (please check one with an [x])

• No documentation update is required

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• Newly added/modified unit tests

[github-actions]

Hi there,

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[jamietanna]

I'm not sure I've seen this behaviour before - please share a case where you're seeing this happen (and the version of Renovate)

Also, when raising PRs, please follow our PR template

[zeitlinger]

Observed with Renovate 43.141.6, and main still appears to behave the same in lib/modules/platform/index.ts + lib/modules/platform/local/index.ts.

Concrete case:

LOG_LEVEL=debug LOG_FORMAT=json \
RENOVATE_CONFIG_FILE=.github/renovate.json5 \
renovate --platform=local --require-config=ignored --dry-run=extract

Expected: effective dryRun=extract, so repository processing stops after extraction.

Actual on the affected versions: local platform init sets dryRun: 'lookup', and initPlatform(config) merges ...config, ...platformInfo, so the explicit CLI/config dryRun=extract is overwritten. In the resulting Combined config log, dryRun is lookup, and repository processing continues into lookup.

The practical symptom we saw was that a caller intentionally invoking local mode with --dry-run=extract still got lookup-phase behavior and datasource/network activity.

The minimal code path behind the behavior is:

• lib/modules/platform/local/index.ts returns dryRun: 'lookup'
• lib/modules/platform/index.ts applies ...config, ...platformInfo
• explicit caller dryRun loses to platform defaults

This PR only changes local platform behavior to preserve an explicit incoming dryRun while keeping the existing default of lookup when none was supplied.

[zeitlinger]

I'm not sure I've seen this behaviour before - please share a case where you're seeing this happen (and the version of Renovate)

Also, when raising PRs, please follow our PR template

My last comment is not a complete repo - please tell me if it's still needed.

[RahulGautamSingh]

Change the PR description to follow the template.

Else, LGTM.

[zeitlinger]

Updated the PR description to follow the template. Thanks!

[viceice]

docs should be updated