Retry guix pull in Guix validation workflows

guix pull keeps hitting transient infrastructure errors (substitute download
failures, git/SSL fetch errors) that abort the run before any package is
tested. Retry the pull up to three times so a single transient blip no longer
fails the workflow; --fallback already covers substitute outages, and the
retry additionally covers git/SSL fetch hiccups.

Author: kdeldycke

.github/workflows/check-guix-click.yaml

@@ -36,7 +36,17 @@ jobs:
               (url "https://codeberg.org/tutu967/guix.git")
               (branch "python-click-8.4.1")))
           CHANNELS
-          guix pull --channels=/tmp/channels.scm --disable-authentication --fallback --verbosity=0
+          # guix pull intermittently fails on transient substitute or git/SSL
+          # errors; retry a few times before giving up.
+          for attempt in 1 2 3; do
+            echo "guix pull attempt ${attempt}..."
+            if guix pull --channels=/tmp/channels.scm --disable-authentication --fallback --verbosity=0; then
+              break
+            fi
+            [ "${attempt}" -eq 3 ] && { echo "guix pull failed after 3 attempts"; exit 1; }
+            echo "retrying in 30s..."
+            sleep 30
+          done
           echo "$HOME/.config/guix/current/bin" >> "$GITHUB_PATH"
 
       - name: Report rebuild scope

.github/workflows/check-guix-deps.yaml

@@ -31,7 +31,17 @@ jobs:
               (url "https://codeberg.org/tutu967/guix.git")
               (branch "mpm-and-dependencies")))
           CHANNELS
-          guix pull --channels=/tmp/channels.scm --disable-authentication --fallback --verbosity=0
+          # guix pull intermittently fails on transient substitute or git/SSL
+          # errors; retry a few times before giving up.
+          for attempt in 1 2 3; do
+            echo "guix pull attempt ${attempt}..."
+            if guix pull --channels=/tmp/channels.scm --disable-authentication --fallback --verbosity=0; then
+              break
+            fi
+            [ "${attempt}" -eq 3 ] && { echo "guix pull failed after 3 attempts"; exit 1; }
+            echo "retrying in 30s..."
+            sleep 30
+          done
           echo "$HOME/.config/guix/current/bin" >> "$GITHUB_PATH"
 
       - name: Lint all new packages