gpush: add --list-rebase mode

--group doesn't test whether pushing with the specified base would
actually work, as that would be slow and is usually not necessary. the
latter will change with some upcoming features.

Change-Id: I545c611bfc48f44350e4eb0fd16853b985b7d4ec
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

1 files changed, 50 insertions, 14 deletions

diff --git a/bin/git-gpush b/bin/git-gpush
index 35d21ae..275b0dc 100755
--- a/bin/git-gpush
+++ b/bin/git-gpush
@@ -145,8 +145,8 @@ Options:
         Reset the base of a previously pushed series to the local branch's
         base. Typically used after a conflicted pull.
 
-        The base-modifying options may be used with --list-online, but
-        their effect is not persisted in this case.
+        The base-modifying options may be used with --list-rebase and
+        --list-online, but their effect is not persisted in this case.
 
     --move {new|<range>}[/<from>]
         After cherry-picking Changes to the current branch, mark the picks
@@ -189,10 +189,13 @@ Options:
         This is a purely off-line operation.
         Implies --all unless 'from' is specified.
 
+    -lr, --list-rebase
+        Like --list, but also verify that the temporary rebasing will
+        succeed.
+
     -ll, --list-online
-        Report all Changes that would be pushed, then quit.
-        The Changes are annotated with state information from Gerrit.
-        Implies --all unless 'from' is specified.
+        Like --list-rebase, but also annotate the Changes with on-line
+        state information from Gerrit.
 
     --aliases
         Report all registered aliases and quit.
@@ -312,6 +315,7 @@ my $push_all = 0;
 my $group_only = 0;
 my $exclude = 0;
 my $list_only = 0;
+my $list_rebase = 0;
 my $list_online = 0;
 
 my @reviewers;
@@ -372,8 +376,12 @@ sub parse_arguments(@)
             $push_all = 1;
         } elsif ($arg eq "-l" || $arg eq "--list") {
             $list_only = 1;
+        } elsif ($arg eq "-lr" || $arg eq "--list-rebase") {
+            $list_only = 1;
+            $list_rebase = 1;
         } elsif ($arg eq "-ll" || $arg eq "--list-online") {
             $list_only = 1;
+            $list_rebase = 1;
             $list_online = 1;
         } elsif ($arg eq "--aliases") {
             foreach my $key (sort(keys %aliases)) {
@@ -453,14 +461,14 @@ sub parse_arguments(@)
         fail("--group and --exclude are mutually exclusive.\n")
             if ($exclude && $not_exclude);
     } elsif ($list_only) {
-        fail("--list/--list-online is incompatible with --quiet/--verbose.\n")
+        fail("--list/--list-rebase/--list-online is incompatible with --quiet/--verbose.\n")
             if ($quiet || ($verbose && !$debug));
-        fail("--list/--list-online is incompatible with series-specific options.\n")
+        fail("--list/--list-rebase/--list-online is incompatible with series-specific options.\n")
             if ($series_specific);
-        fail("--list/--list-online is incompatible with push-modifying options.\n")
-            if ($push_specific || (!$list_online && $minimal_override));
+        fail("--list/--list-rebase/--list-online is incompatible with push-modifying options.\n")
+            if ($push_specific || (!$list_rebase && $minimal_override));
         fail("--list is incompatible with base-modifying options.\n")
-            if (defined($ref_base) && !$list_online);
+            if (defined($ref_base) && !$list_rebase);
     } elsif ($push_all) {
         fail("--all is incompatible with series-specific options.\n")
             if ($series_specific);
@@ -1670,6 +1678,28 @@ sub classify_changes_offline($)
     }
 }
 
+sub classify_changes_offline_rebase($)
+{
+    my ($group) = @_;
+
+    my $changes = $$group{changes};
+    foreach my $change (@$changes) {
+        my $commit = $$change{final};
+        next if (!$commit);  # Rebase failure
+        my $pushed = $$change{pushed};
+        if (defined($pushed)) {
+            my $sha1 = $$commit{id};
+            if ($pushed ne $sha1) {
+                $$change{freshness} = MODIFIED;
+            } else {
+                $$change{freshness} = UNMODIFIED;
+            }
+        } else {
+            $$change{freshness} = NEW;
+        }
+    }
+}
+
 my $have_rejected = 0;
 my $have_modified = 0;
 my $need_force = 0;
@@ -2039,7 +2069,8 @@ sub execute_grouping()
     resolve_ref_base();
     # We could rebase here, as that would tell us whether the desired
     # grouping is feasible (re dependencies) early on. However, it would
-    # significantly slow down the operation for this little benefit.
+    # significantly slow down the operation for this little benefit. The
+    # use case is covered by the --list-rebase option instead.
     # We also don't query Gerrit, as online-classifying unrebased Changes
     # yields mostly irrelevant and potentially even confusing annotations;
     # branch tracking is not necessary here, either.
@@ -2053,6 +2084,7 @@ sub execute_grouping()
 
 sub execute_pushing()
 {
+    my $rebase = !$list_only || $list_rebase;
     my $online = !$list_only || $list_online;
     my ($groups, $all_groups);
     if ($push_all) {
@@ -2096,7 +2128,7 @@ sub execute_pushing()
     foreach my $group (@$groups) {
         determine_topic($group);
     }
-    if ($online) {
+    if ($rebase) {
         # Rebasing may take a while, so make sure all base determination
         # errors are reported before we start.
         foreach my $group (@$groups) {
@@ -2109,7 +2141,11 @@ sub execute_pushing()
         rebase_groups($groups, $upstreamed_changes);
         foreach my $group (@$groups) {
             if (defined($$group{gid})) {
-                classify_changes_online($group);
+                if ($online) {
+                    classify_changes_online($group);
+                } else {
+                    classify_changes_offline_rebase($group);
+                }
             } else {
                 # We don't rebase sets of loose Changes, as this will often
                 # create garbage or fail. We can get here only in --list mode.
@@ -2124,7 +2160,7 @@ sub execute_pushing()
     if ($list_only) {
         show_changes($all_groups);
         print "Not pushing - list mode.\n" if ($debug);
-        update_rebase_cache($groups) if ($online);
+        update_rebase_cache($groups) if ($rebase);
     } else {
         print_errors($groups);
         show_changes($groups) if (!$quiet);