6053e1ee4c
PyYAML raises a ScannerError on a tab used anywhere outside a quoted
scalar (leading/trailing/embedded in a plain value, immediately before or
after a key colon, or as indentation) and yields no token, accepting tabs
ONLY inside single/double-quoted scalars. The conservative block-YAML
fallback in get_gitea_token_for_login normalized those tabs away -- via
_scalar's top-level .strip(), _KEY_RE's [ \t] separators, _Parser.__init__'s
body.rstrip(), parse_seq's body[1:].strip(), and the inline-map emptiness
checks -- and still emitted the login token: a credential fail-open in the
dangerous direction (less conservative than PyYAML).
Extend the whole-document "only ever more conservative than PyYAML, never
less" invariant to tab/scanner parity:
- _KEY_RE now uses SPACE-only separators (` *:` / `[ ](.*)`), so a tab in a
key/value separator makes the line fail to match and the caller fails closed.
- Every whitespace-normalization site strips SPACES only (strip(" ")/rstrip(" "))
so a tab survives to a fail-closed guard instead of being silently removed:
_scalar top-level strip, quoted-trailing strip, post-comment strip,
_Parser.__init__ body rstrip, parse_seq item strip, and the three inline
emptiness checks.
- _scalar fails closed on any tab remaining in a plain scalar.
Tabs strictly inside quoted scalars are preserved verbatim (unchanged parity),
matching exactly what PyYAML accepts.
Verified empirically against PyYAML 6.0.3: ScannerError for each rejected
tab position; string-preserved for quoted inner tabs. Differential fuzz with
tab re-included: 0 fail-opens over ~6000 inputs; 0 over-rejection across 220
PyYAML-accepted quoted-tab cases. Adds section 17 to the regression harness
(fail-close fixtures for trailing/leading/embedded/after-colon/indentation
tabs; parity fixtures for double- and single-quoted inner tabs).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Git provider wrappers
These scripts provide host-aware GitHub and Gitea issue, pull-request, milestone, and CI operations.
Durable review provenance
A successful provider write command—or a wrapper message based only on that command's exit code—is not durable review provenance. Review comments, approvals, and change requests count as durable provenance only after the wrapper reads the created provider record back and verifies that it was created by this write.
The write is a direct Gitea REST POST that returns the created record's id. Neither wrapper writes through tea — tea 0.11.1 can silently no-op while exiting 0 and cannot emit the id of a record it creates, so its exit code is worthless as proof of a durable write (#865). Instead:
- Comments (
issue-comment.sh, and thecommentaction ofpr-review.sh)POST /api/v1/repos/{owner}/{repo}/issues/{index}/comments, requiring a201and parsing the created comment'sidfrom the response body. - Reviews (
approve/request-changes)POST /api/v1/repos/{owner}/{repo}/pulls/{index}/reviewswith theevent(APPROVED/REQUEST_CHANGES), the reviewbody, andcommit_idpinned to the PR's current head, then parse the created review'sid. The review body travels in the review submit itself — there is no separate detached comment to reconcile (a GiteaREQUEST_CHANGESreview requires a non-empty body, which the submit carries).
Verification keys on that exact provider-returned id. The wrapper then GETs that one record directly — GET /issues/comments/{id} or GET /pulls/{n}/reviews/{id} — and requires that its id equals the created id, its author login equals the acting identity (resolved via GET /api/v1/user for the token in use), and, for comments, its body exactly matches what was submitted and its returned web URL belongs to this exact provider and repository (the issue_url / pull_request_url origin — scheme, host, and effective port — and full path, i.e. deployment prefix + exact owner/repo + kind + number, must match; a suffix/endsWith test would accept a look-alike host or a decoy path prefix, so the whole normalized URL is compared). The comment action of pr-review.sh additionally requires the returned resource be a pull request (a populated pull_request_url); a bare issue_url is rejected, so if issue #N exists but PR #N does not, an issue comment cannot be reported as a verified PR comment. (issue-comment.sh legitimately keeps the broader issue-or-PR acceptance.) For reviews, its state matches the requested action, its reviewed commit_id equals the PR head, and its persisted body equals the submitted body — an exact, presence- and type-checked equality (a missing/null persisted body no longer counts as an empty match), because Gitea can finalize/reuse a pending review id whose stored content was authored elsewhere, so the body is bound too. The write, the /user identity lookup, and the read-back all use the same credential — the effective login's token, or the host credential when no login is named — so the write is verified against the identity that actually performed it.
A review's pinned head is re-checked after verification (current-head TOCTOU). The commit_id is pinned to the PR head read before the submit; between that read and the read-back the branch could advance (a force-push or a new commit), leaving a verified review attached to a now-superseded commit while the live tip carries unreviewed code. After the exact-id read-back succeeds, the wrapper re-reads the live PR head (GET …/pulls/{n}) and requires it still equals the submitted SHA; if the head advanced it fails closed (non-zero, no success line) rather than reporting a review that no longer covers the PR's current commit.
This closes the concurrency window rather than documenting it. Because verification keys on the id the create returned, a no-op create yields no id and fails closed with no list-scan fallback, and a concurrent record — even one written by the same identity with an identical body/state — has a different id and cannot be mistaken for this write. There is no residual same-identity window: the earlier boundary-and-author heuristic (accept any id > pre-write-max with a matching author) is replaced entirely by exact-id attribution.
Exact-id read-back is the sole authority. Verification is a direct GET of the one record the create returned; there is no follow-up list enumeration. An earlier redundant pass that re-listed the record's page (?limit=&page=1,2,…) was removed: server-capped page sizes and list-pagination quirks made it a false-failure source (a durable, exact-id-verified record could be missed by a non-exhaustive enumeration), and it added nothing over the authoritative exact-id GET.
Credential handling
The Gitea API token is never passed on a curl command line. An Authorization: token <value> argument would be visible to any local process that can read the process table (ps / /proc/<pid>/cmdline) for the lifetime of the request. Instead, every authenticated curl call writes the header into a private, mode-0600 config file under $TMPDIR and passes it with curl --config <file> (gitea_write_auth_config), so only the file path — never the token — appears in argv. Each such file is unlinked on every exit path (success and failure) by the caller's RETURN trap.
tea invocation notes (Gitea)
- tea v0.11.1 has no
commentsubcommand undertea prortea issue— thetea pr comment/tea issue commentforms don't error, they silently fall through to a no-op and still exit 0, producing a false-success write (#865). tea's write subcommands (tea comment,tea pr approve/reject) also cannot report the id of the record they create, so their exit code cannot prove a durable write. These wrappers therefore do not write reviews or comments throughteaat all; they use direct Gitea RESTPOSTs that return the created record's id (see "Durable review provenance" above).teais consulted only to enumerate the login list for host→login resolution. - Because the review body is carried in the
POST …/reviewssubmit itself, there is no separate detached review comment, and the historicaltea pr approve/rejecttrailing-positional-argument vs. nonexistent--comment/-commentflag hazard (#835) no longer applies to these wrappers — no review comment is ever passed totea.
--login override
Both pr-review.sh and issue-comment.sh accept an optional --login <name> flag that overrides the automatically detected Gitea login for that single invocation. The override selects which credential the REST write, the /user identity lookup, and the read-back all use — its token is resolved from the tea config for that login name (get_gitea_token_for_login), falling back to the repo host's credential when no login is named. The resolved login is host- and port-bound: the login's configured URL host and effective port (the scheme's default port — 80 for http, 443 for https — applies when a port is omitted, symmetrically on both sides) must match the repo remote's, so a login name shared across hosts (or an override configured for a different Gitea, including one on a different port of the same host) can never send one host's credential to another — a host or port mismatch fails closed rather than leaking a cross-host token. Resolving the acting identity and the read-back from the same login that performs the write is essential: a write performed under an overridden login must be verified against that login's identity, not the host default's. Callers who need a different login than the host default should pass --login <reviewer-login>.
As a durable successor to this mechanism, consider giving each reviewer/approver slot its own dedicated Gitea login credential, so that author≠reviewer holds at the credential level rather than relying on wrapper-level --login bookkeeping. This is a recommendation for future hardening, not something implemented by this flag.