doc: './pre-inst-env guix pull' won't upgrade local source tree.

* doc/contributing.texi (Running Guix Before It Is Installed): Clarify
  './pre-inst-env guix pull' won't upgrade local source tree.
* doc/guix.texi (Invoking guix pull): Mention ~/.config/guix/latest.

Co-authored-by: Ludovic Courtès <ludo@gnu.org>

2 files changed, 8 insertions, 1 deletions

diff --git a/doc/contributing.texi b/doc/contributing.texi
index f855daf2dab..cdc3f6d2d74 100644
--- a/doc/contributing.texi
+++ b/doc/contributing.texi
@@ -116,6 +116,11 @@ $1 = 361
 The @command{pre-inst-env} script sets up all the environment variables
 necessary to support this, including @env{PATH} and @env{GUILE_LOAD_PATH}.
 
+Note that @command{./pre-inst-env guix pull} does @emph{not} upgrade the
+local source tree; it simply updates the @file{~/.config/guix/latest}
+symlink (@pxref{Invoking guix pull}).  Run @command{git pull} instead if
+you want to upgrade your local source tree.
+
 
 @node The Perfect Setup
 @section The Perfect Setup
diff --git a/doc/guix.texi b/doc/guix.texi
index 3afa496ea39..836a0b4e0e8 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -1814,7 +1814,9 @@ On completion, @command{guix package} will use packages and package
 versions from this just-retrieved copy of Guix.  Not only that, but all
 the Guix commands and Scheme modules will also be taken from that latest
 version.  New @command{guix} sub-commands added by the update also
-become available.
+become available@footnote{Under the hood, @command{guix pull} updates
+the @file{~/.config/guix/latest} symbolic link to point to the latest
+Guix, and the @command{guix} command loads code from there.}.
 
 The @command{guix pull} command is usually invoked with no arguments,
 but it supports the following options: