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zit Erratum — draft-fossil-sync-protocol-01 §5.3
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Erratum — draft-fossil-sync-protocol-01 §5.3
Document draft-fossil-sync-protocol-01
Section 5.3 — Comment Lines (the value of N in the timestamp comment)
Type Technical (N is never defined; receivers are told not to act on it)
Status Applied in draft-fossil-sync-protocol-01 (2026-10-12)
Reported 2026-10-12
Submitter Dan Mestas
Found via A reader implementing §5.3 from the text alone

1. Summary

§5.3 gives the syntax of # timestamp DATETIME errors N and says N is informational, but never says what N counts. A sender has nothing to put there.

2. Location

§5.3, the paragraph beginning "DATETIME is exactly 19 bytes".

3. The reference behavior

Fossil 2.28 page_xfer() keeps a counter nErr (src/xfer.c:1278) that is incremented at each error card the server's own card handling emits: wrong project, the authorization refusals, multiple or failed login, the file, cfile and uvfile handler failures, and the script failures (:1330-1904). The closing comment prints it (:1970). The counter records errors raised, not cards present: a later reset discards the cards of earlier errors but not their count, so a push refused at :1517 followed by a file card refused at :1363 leaves one error card and errors 2. Three error cards are never counted: the unknown-operator bad command error (:1893), the private-content refusal emitted by server_private_xfer_not_authorized() (:1138-1140), and the SHA3 version refusal emitted by xfer_cannot_send_sha3_error() (:523-527), which is why Appendix A.2 shows that error followed by errors 0.

4. Impact

Cosmetic. N is informational and no receiver acts on it, but a cleanroom sender needs a definition.

5. Correction

    additional internal validation; DATETIME estimates skew, while N is
-   informational and not a wire error.
+   informational and not a wire error.  N counts the errors the
+   server raised while handling the request; it can exceed the error
+   cards present, because a reset discards earlier output.  Fossil's
+   server does not count the unknown-operator error, the private-
+   content refusal, or the SHA3 version refusal.  A receiver MUST NOT
+   act on N.

6. Rationale

Defines N as what Fossil's counter holds, records the three cards Fossil leaves out and the reset effect so a byte-comparing test is not surprised, and keeps N informational.

7. Verification