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| author | Oleg Zaytsev <mail@olegzaytsev.com> | 2025-12-26 20:11:01 +0000 |
|---|---|---|
| committer | Cherry Mui <cherryyz@google.com> | 2025-12-29 12:45:08 -0800 |
| commit | 0b06b68e21a3fbc75b3dd87c644da94828483a36 (patch) | |
| tree | 5b44033d187e3a7964680d1bd043ddc96c27de24 | |
| parent | 9cb3edbfe9eb68113453cdaa436db31d28577ab8 (diff) | |
| download | go-0b06b68e21a3fbc75b3dd87c644da94828483a36.tar.xz | |
encoding/gob: clarify docs about pointers to zero values not being sent
The documentation on encoding/gob mentions that pointers are flattened,
and it also explicitly says that empty values are not sent.
A corollary of this, is that pointers to zero values are not sent, i.e.,
gob-encoding of *false becomes nil on the receiver side.
It is worth documenting this explicitly.
Change-Id: I1909203b8972e20791144bdda22e5f1b466aad97
GitHub-Last-Rev: 57764ec235ffe48484be98d3ed5269f0102ca4f8
GitHub-Pull-Request: golang/go#77009
Reviewed-on: https://go-review.googlesource.com/c/go/+/732820
Reviewed-by: Roland Shoemaker <roland@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Sean Liao <sean@liao.dev>
Reviewed-by: Cherry Mui <cherryyz@google.com>
| -rw-r--r-- | src/encoding/gob/doc.go | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/src/encoding/gob/doc.go b/src/encoding/gob/doc.go index c746806887..390f25088e 100644 --- a/src/encoding/gob/doc.go +++ b/src/encoding/gob/doc.go @@ -153,16 +153,16 @@ are transmitted, even if all the elements are zero. Structs are sent as a sequence of (field number, field value) pairs. The field value is sent using the standard gob encoding for its type, recursively. If a -field has the zero value for its type (except for arrays; see above), it is omitted -from the transmission. The field number is defined by the type of the encoded -struct: the first field of the encoded type is field 0, the second is field 1, -etc. When encoding a value, the field numbers are delta encoded for efficiency -and the fields are always sent in order of increasing field number; the deltas are -therefore unsigned. The initialization for the delta encoding sets the field -number to -1, so an unsigned integer field 0 with value 7 is transmitted as unsigned -delta = 1, unsigned value = 7 or (01 07). Finally, after all the fields have been -sent a terminating mark denotes the end of the struct. That mark is a delta=0 -value, which has representation (00). +field has the zero value for its type (except for arrays; see above) or it's a +pointer to a zero value, it is omitted from the transmission. The field number +is defined by the type of the encoded struct: the first field of the encoded type +is field 0, the second is field 1, etc. When encoding a value, the field numbers +are delta encoded for efficiency and the fields are always sent in order of +increasing field number; the deltas are therefore unsigned. The initialization +for the delta encoding sets the field number to -1, so an unsigned integer field 0 +with value 7 is transmitted as unsigned delta = 1, unsigned value = 7 or (01 07). +Finally, after all the fields have been sent a terminating mark denotes the end +of the struct. That mark is a delta=0 value, which has representation (00). Interface types are not checked for compatibility; all interface types are treated, for transmission, as members of a single "interface" type, analogous to |