fix: correct function name length in validation error message to 63

[ree-rishun]

Description

Fixes two inaccuracies in the function name validation error message in functionIdsAreValid() (src/deploy/functions/validate.ts). The message disagreed with both the validation regex /^[a-zA-Z][a-zA-Z0-9_-]{0,62}$/ and the function's own JSDoc comment:

1. Character limit (62 → 63): The message said names must "not exceed 62 characters in length", but the regex allows 63 characters (1 leading letter + up to 62 additional characters), and the JSDoc comment also states "not exceed 63 characters in length". As a result, a 63-character function name deploys successfully, yet the message claimed the limit was 62 — misleading users into thinking valid names are invalid.

2. Missing underscores: The message listed only "letters, numbers, hyphens", but the regex ([a-zA-Z0-9_-]) and the JSDoc comment both allow underscores. Underscores were silently omitted from the user-facing message.

This change updates the message so it is consistent with the regex, the JSDoc comment, and the messages already used elsewhere (e.g. applyPrefix() in src/deploy/functions/build.ts, which says "maximum length of 63 characters").

- numbers, hyphens, and not exceed 62 characters in length
+ numbers, underscores, hyphens, and not exceed 63 characters in length

Note: this validation also rejects names that don't start with a letter or contain other invalid characters. This PR only corrects the wording of the error message and does not change any validation behavior.

Scenarios Tested

• Ran npm test locally; compilation and the existing test suite pass.
• Deployed functions to a separate Firebase project and confirmed in the console that the deploys succeeded for both a 63-character name and a name containing underscores (e.g. my_func), verifying that 63 is the true limit (not 62) and that underscores are allowed.
• This is a message-only change; no validation logic was modified.

$ TZ='America/Los_Angeles' npm test

... (truncated) ...

  4506 passing (38s)
  10 pending

... (coverage table truncated) ...

Sample Commands

No command or flag changes. The corrected error surfaces during deploy:

$ firebase deploy --only functions
Error: 1nnnnnnnnn function name(s) can only contain letters, numbers, underscores, hyphens, and not exceed 63 characters in length

[google-cla]

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[gemini-code-assist]

Code Review

This pull request updates the validation error message in src/deploy/functions/validate.ts to reflect the correct maximum length of 63 characters for function names. The reviewer pointed out that the error message should also be updated to include underscores, which are allowed by the validation regex.

[IzaakGough]

This looks good to me, nice work! The failing CI check is unrelated to this PR.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
⚠️ Please upload report for BASE (main@7e8582d). Learn more about missing BASE report.

Additional details and impacted files

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