From f4ed8ebfe2bce2bbafcff1c3d444fd9e34d8fd4e Mon Sep 17 00:00:00 2001
From: Adam Williamson <awilliam@redhat.com>
Date: Nov 28 2016 20:44:23 +0000
Subject: Use checksum (not mtime) to check if filelist changed


My mirror files are on an NFS share, which seems to mess with
the mtime check. That seems like a slightly fragile approach
anyhow, so why not just md5sum the list? This re-purposes the
fltimes array, which AFAICS was never used for anything at all,
as a checksums array and uses md5sum for the 'file list did not
change, bail out now' check. Also entirely removes the disabled
diffing code; having commented-out old stuff all over the place
is awful for readability, the commit history is the correct
place to memorialize old mistakes ;)

---

diff --git a/quick-fedora-mirror b/quick-fedora-mirror
index bf2d838..3b57a7e 100755
--- a/quick-fedora-mirror
+++ b/quick-fedora-mirror
@@ -388,21 +388,15 @@ sep
 logit o Remote file list download start
 db2 Downloading file lists
 # ZSHISM (declare associative array)
-typeset -A fltimes
+typeset -A checksums
 for module in $MODULES; do
     # ZSHISM? (associative array indexing)
     moduledir=$MODULEMAPPING[$module]
     mkdir $moduledir
     flname=${FILELIST/'$mdir'/$moduledir}
-
-    # ZSHISM (assign assoc. array value)
-    fltimes[$module]=0
     if [[ -f $DESTD/$moduledir/$flname ]]; then
-        cp -p $DESTD/$moduledir/$flname $moduledir
-        # So that we can diff it later
-        cp -p $moduledir/$flname $flname.old
         # ZSHISM (assign assoc. array value)
-        fltimes[$module]=$(stat --format=%Y $moduledir/$flname)
+        checksums[$module]=$(sha1sum $DESTD/$moduledir/$flname | cut -d' ' -f1)
     fi
 
     echo $moduledir/$flname >> filelist-transferlist
@@ -431,9 +425,9 @@ for module in $MODULES; do
     # First fetch each filefiletimelist, and make one big transfer list from
     # all of them.  Copy in the old file from our repo to speed up rsync in case
     # most of it didn't change
-    if [[ -z $alwayscheck && -f $fl.old && $(stat --format=%Y $fl.old) == $(stat --format=%Y $fl) ]]; then
-        logit N No change in file list time for $module
-        db2 No change in file list mtime.  Skipping $module.
+    if [[ -n $checksums[$module] ]] && [[ $(sha1sum $fl | cut -d' ' -f1) == $checksums[$module] ]]; then
+        logit N No change in file list for $module
+        db2 No change in file list checksum.  Skipping $module.
         continue
     fi
 
@@ -441,12 +435,6 @@ for module in $MODULES; do
     logit P Processing start: $module
     db2 Processing $module
 
-    # Diffing the whole thing is not really useful
-    #if [[ $VERBOSE -ge 6 && -f $fl.old ]]; then
-    #    echo "Changes in file list since last run:"
-    #    diff -u $fl.old $fl
-    #fi
-
     flversion=$(awk -F '\t' '/^\[Version/ {s=1; next} /^$/ {exit} {if (s) print $0}' < $fl)
     if [[ "$flversion" != '2' ]]; then
         (>&2 echo File list version from the mirror cannot be processed by this script.