sync: Provide a CLI command to opt in/out of smartsync for a user.v2.70

Add a boolean `sync.smartsync` setting in the per-user repo config
(~/.repoconfig/config):
* true: smart sync by default, as if -s were passed.
* false: never smart sync by default, even if the manifest enables it.
* unset: follow the manifest default, as before.

Add docs/repoconfig.md as the user facing documentation for
~/.repoconfig/config and its settings, and point smart-sync.md and the
`repo sync` help at it.

Bug: 569927750
Test: ./run_tests
Change-Id: Ideb4119fcb5e90f8bb35c493d9e4f8bec7878b77
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/643264
Reviewed-by: Gavin Mak <gavinmak@google.com>
Commit-Queue: Insaf Latypov <saferif@google.com>
Tested-by: Insaf Latypov <saferif@google.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/man/repo-sync.1 b/man/repo-sync.1
index b033a906f..2c7467e1f 100644
--- a/man/repo-sync.1
+++ b/man/repo-sync.1
@@ -1,5 +1,5 @@
 .\" DO NOT MODIFY THIS FILE!  It was generated by help2man.
-.TH REPO "1" "September 2026" "repo sync" "Repo Manual"
+.TH REPO "1" "October 2026" "repo sync" "Repo Manual"
 .SH NAME
 repo \- repo sync - manual page for repo sync
 .SH SYNOPSIS
@@ -188,6 +188,10 @@ The \fB\-s\fR/\-\-smart\-sync option can be used to sync to a known good build a
 specified by the manifest\-server element in the current manifest. The
 \fB\-t\fR/\-\-smart\-tag option is similar and allows you to specify a custom tag/label.
 .PP
+Whether 'repo sync' smart syncs by default can also be controlled with the
+sync.smartsync per\-user setting; see docs/repoconfig.md. Explicit
+\fB\-s\fR/\-\-no\-smart\-sync/\-t flags always override it.
+.PP
 The \fB\-u\fR/\-\-manifest\-server\-username and \fB\-p\fR/\-\-manifest\-server\-password options can
 be used to specify a username and password to authenticate with the manifest
 server when using the \fB\-s\fR or \fB\-t\fR option.