migrate_tree.pl: Only write a new commits file, if the old was finished reading or...

diff --git a/pwx/migrate_tree.pl b/pwx/migrate_tree.pl
index c5892c7178d39bf3399ac269e7dcfadce6793aea..4eb358ec0aa29a8d012b897efaade8d3f506d7cb 100755 (executable)
--- a/pwx/migrate_tree.pl
+++ b/pwx/migrate_tree.pl
@@ -11,7 +11,8 @@
 # 0.1.0    2018-05-14  sed, PrydeWorX  Application of the reworked patches added.
 # 0.2.0    2018-05-15  sed, PrydeWorX  First working version.
 # 0.2.1                                Fixed usage of Try::Tiny.
-# 0.2.2    2018-05-16  sed, PrydeWorX  Made sure that the commit file is always written on exit.
+# 0.2.2    2018-05-16  sed, PrydeWorX  Made sure that the commit file is always written on exit,
+#                                        but only if a potential commits file was finished reading.
 #
 # ========================
 # === Little TODO list ===
@@ -79,6 +80,7 @@ Notes:
 # ================================================================
 
 my $commit_count   = 0;   # It is easiest to count the relevant commits globally.
+my $commits_read   = 0;   # Set to one once the commit file is completely read.
 my $do_advance     = 0;   # If set by --advance, use src-<hash> as last commit.
 my %hSrcCommits    = ();  # Record here which patch file is which commit.
 my %hDirectories   = ();  # Filled when searching relevant files, used to validate new files.
@@ -650,6 +652,9 @@ sub get_last_mutual {
                checkout_tree($upstream_path, $wanted_refid, 0);
        } ## end if ( -f $COMMIT_FILE )
 
+       # Note down that reading of any file is done.
+       $commits_read = 1;
+
        # If this is already set, we are fine.
        if ( length($mutual_commit) ) {
                $hMutuals{$upstream_path}{$wanted_refid}{mutual} = shorten_refid($upstream_path, $mutual_commit);
@@ -936,6 +941,10 @@ sub rework_patch {
 # --- Write back %hMutuals to $COMMIT_FILE ---
 # --------------------------------------------
 sub set_last_mutual {
+
+       # Don't do anything if we haven't finished reading the commit file:
+       $commits_read or return 1;
+
        my $out_text = "# Automatically generated commit information\n"
                     . "# Only edit if you know what these do!\n\n";
        my ($pLen, $rLen, $mLen, $sLen) = (0, 0, 0, 0); # Length for the fmt