refactor: rename remaining BIP14 subversion identifiers to user agent #34444

pull l0rinc wants to merge 2 commits into bitcoin:master from l0rinc:l0rinc/rename-user-agent changing 28 files +93 −93

l0rinc commented at 1:24 PM on January 29, 2026: contributor

Problem

BIP14 defines the sub_version_num field in version messages as a user-agent string, but there are still internal and user-facing references to "subver/subversion" (as noted in #34389 (review)).

Fix

The first commit performs the bulk of the mechanical work via a scripted-diff that (with a leading preflight check to make sure the target names don't collide), renaming internal identifiers from *SubVersion*/subver* to *UserAgent*/user_agent. I have verified the mechanical renames via to produce the same binary (except for the test_FormatSubVersion unit test name).

The second commit follows up with the remaining non-mechanical cleanup, adjusting user-facing descriptions, comments, and local variable names to use "user agent" and explicitly referencing BIP14 as justification.

For compatibility, the RPC keys (subver, subversion) are intentionally left unchanged.

scripted-diff: rename subversion identifiers to user agent

BIP14 specifies that the `sub_version_num` field is a user agent string.
A few values can safely be renamed automatically.

-BEGIN VERIFY SCRIPT-
git grep -qE 'FormatUserAgent|formatUserAgent|strUserAgent|MAX_USER_AGENT_LENGTH|cleanUserAgent|m_user_agent_mutex|USER_AGENT_COLUMN_WIDTH|P2P_USER_AGENT' -- src test/functional && echo "Error: Target identifiers already exist in src/ or test/functional" && exit 1

git grep -lE 'FormatSubVersion|formatSubVersion|strSubVersion|MAX_SUBVERSION_LENGTH|cleanSubVer|m_subver_mutex|SUBVERSION_COLUMN_WIDTH|P2P_SUBVERSION|strSubVer|Subversion' -- src test/functional | \
  xargs sed --in-place \
    -e 's/FormatSubVersion/FormatUserAgent/g' \
    -e 's/formatSubVersion/formatUserAgent/g' \
    -e 's/strSubVersion/strUserAgent/g' \
    -e 's/MAX_SUBVERSION_LENGTH/MAX_USER_AGENT_LENGTH/g' \
    -e 's/cleanSubVer/cleanUserAgent/g' \
    -e 's/m_subver_mutex/m_user_agent_mutex/g' \
    -e 's/SUBVERSION_COLUMN_WIDTH/USER_AGENT_COLUMN_WIDTH/g' \
    -e 's/P2P_SUBVERSION/P2P_USER_AGENT/g' \
    -e 's/strSubVer/user_agent/g' \
    -e 's/Subversion/UserAgent/g'
-END VERIFY SCRIPT-

7d59e5379b

doc,rpc,test: refer to BIP14 user agent

BIP14 specifies that the `sub_version_num` field is a user agent string.
Update user-facing text, comments, and local variable names accordingly, while keeping RPC keys ("subver", "subversion") unchanged for compatibility.

5636c68453

DrahtBot commented at 1:25 PM on January 29, 2026: contributor


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Reviews

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Type Reviewers

Concept NACK ajtowns

Concept ACK naiyoma

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Conflicts

Reviewers, this pull request conflicts with the following ones:
- #34389 (net/log: standardize peer+addr log formatting via LogPeer by l0rinc)
- #34293 (Bugfix: net_processing: Restore missing comma between peer and peeraddr in "receive version message" and "New ___ peer connected" by luke-jr)
- #34181 (refactor: [p2p] Make ProcessMessage private again, Use references when non-null by maflcko)
If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.



LLM Linter (✨ experimental)

Possible places where named args for integral literals may be used (e.g. func(x, /*named_arg=*/0) in C++, and func(x, named_arg=0) in Python):
- check_bytesrecv(peer, msg_type, min_bytes_recv) in test/functional/test_framework/test_framework.py
<sup>2026-01-29 13:25:27</sup>
l0rinc renamed this:
~~refactor/BIP14: rename remaining subversion identifiers to user agent~~
refactor: rename remaining BIP14 subversion identifiers to user agent
on Jan 29, 2026
DrahtBot added the label Refactoring on Jan 29, 2026
naiyoma commented at 7:50 PM on February 6, 2026: contributor

Concept ACK

Changes align with proposal:-> https://github.com/bitcoin/bips/blob/master/bip-0014.mediawiki#proposal

"The currently unused sub_version_num field in "version" packets will become the new user-agent string."

I grepped twice to check on the remaining instance git grep -i "subver" -- src test/functional git grep -i "subver" -- ':!src' ':!test/functional

Other than the RPC keys. These changes also do not touch the release notes and doc/bips.md, which should be left as-is.
ajtowns commented at 9:19 PM on February 6, 2026: contributor

Concept NACK. This touches 28 files for a purely cosmetic rename — the merge conflict cost (already 3 conflicting PRs) and git blame churn outweigh the naming consistency benefit IMO.

The internal terminology has been "subversion" for 15 years and is well-understood by anyone working on this code. BIP 14 defined how we format the string, and introduced the separation between protocol and client version, but I don't think it obligates us to match its naming internally. (Personally, I think "subversion" is a nice string to have peppered through our codebase anyway)

If the concern is that bips.md's description feels inaccurate, note that the entry already has a bug: it cites #669 (multisig/OP_EVAL) but the actual BIP 14 implementation was #707.

(** Using AI to edit my NACKs to make them less mean)
l0rinc commented at 9:28 PM on February 6, 2026: contributor

Thanks for the feedback.
l0rinc closed this on Feb 6, 2026
l0rinc deleted the branch on Feb 27, 2026

Type	Reviewers
Concept NACK	ajtowns
Concept ACK	naiyoma

Contributors

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#34389 net/log: standardize peer+addr log formatting via `LogPeer`

refactor: rename remaining BIP14 subversion identifiers to user agent #34444

Problem

Fix

Reviews

Conflicts

LLM Linter (✨ experimental)