Update prior installer versions def. branch

Signed-off-by: Chris Evich <cevich@redhat.com>

bin/install_automation.sh

@@ -44,6 +44,22 @@ msg() { echo -e "${1:-No Message given}" > /dev/stderr; }
 
 dbg() { if ((DEBUG)); then msg "\n# $1"; fi }
 
+# On 5/14/2021 the default branch was renamed to 'main'.
+# Since prior versions of the installer reference the old
+# default branch, the version-specific installer could fail.
+# Work around this with some inline editing of the downloaded
+# script, before re-exec()ing it.
+fix_branch_ref() {
+    local filepath="$1"
+    if [[ ! -w "$filepath" ]]; then
+        msg "Error updating default branch name in installer script at '$filepath'"
+        exit 19
+    fi
+    sed -i -r -e \
+        's/^(AUTOMATION_REPO_BRANCH.+)master/\1main/' \
+        "$filepath"
+}
+
 # System-wide access to special environment, not used during installer testing.
 install_environment() {
     msg "##### Installing automation environment file."
@@ -170,6 +186,7 @@ exec_installer() {
     # Full path is required so script can find and install itself
     DOWNLOADED_INSTALLER="$INSTALLATION_SOURCE/bin/$SCRIPT_FILENAME"
     if [[ -x "$DOWNLOADED_INSTALLER" ]]; then
+        fix_branch_ref "$DOWNLOADED_INSTALLER"
         msg "Executing installer version '$version_arg'\n"
         dbg "Using \$INSTALL_PREFIX '$INSTALL_PREFIX'; installer '$DOWNLOADED_INSTALLER'"
         # Execution likely trouble-free, cancel removal on exit

common/test/testbin-install_automation.sh

@@ -27,6 +27,16 @@ test_cmd \
     128 "fatal.+v99.99.99.*not found" \
     $INSTALLER_FILEPATH 99.99.99
 
+test_cmd \
+    "The installer successfully installs the oldest tag" \
+    0 "installer version 'v1.0.0'.+exec.+AUTOMATION_REPO_BRANCH=main.+Installation complete" \
+    $INSTALLER_FILEPATH 1.0.0
+
+test_cmd \
+    "The oldest installed installer's default branch was modified" \
+    0 "" \
+    grep -Eqm1 '^AUTOMATION_REPO_BRANCH=.+main' "$INSTALL_PREFIX/automation/bin/$SUBJ_FILENAME"
+
 test_cmd \
     "The installer detects incompatible future installer source version by an internal mechanism" \
     10 "Error.+incompatible.+99.99.99" \