git-gui: allow undoing last revert

Accidental clicks on the revert hunk/lines buttons can cause loss of
work, and can be frustrating. So, allow undoing the last revert.

Right now, a stack or deque are not being used for the sake of
simplicity, so only one undo is possible. Any reverts before the
previous one are lost.

Signed-off-by: Pratyush Yadav <me@yadavpratyush.com>

diff --git a/git-gui.sh b/git-gui.sh
index 15925448309272bbec6481c6d6bb821c5a3f1284..e03a2d2c28d7170ab18b9751f10ebb624ad67499 100755 (executable)
--- a/git-gui.sh
+++ b/git-gui.sh
@@ -1350,6 +1350,8 @@ set is_submodule_diff 0
 set is_conflict_diff 0
 set selected_commit_type new
 set diff_empty_count 0
+set last_revert {}
+set last_revert_enc {}
 
 set nullid "0000000000000000000000000000000000000000"
 set nullid2 "0000000000000000000000000000000000000001"
@@ -3601,6 +3603,11 @@ $ctxm add command \
        -command {apply_or_revert_range_or_line $cursorX $cursorY 1; do_rescan}
 set ui_diff_revertline [$ctxm index last]
 lappend diff_actions [list $ctxm entryconf $ui_diff_revertline -state]
+$ctxm add command \
+       -label [mc "Undo Last Revert"] \
+       -command {undo_last_revert; do_rescan}
+set ui_diff_undorevert [$ctxm index last]
+lappend diff_actions [list $ctxm entryconf $ui_diff_undorevert -state]
 $ctxm add separator
 $ctxm add command \
        -label [mc "Show Less Context"] \
@@ -3680,7 +3687,7 @@ proc has_textconv {path} {
 }
 
 proc popup_diff_menu {ctxm ctxmmg ctxmsm x y X Y} {
-       global current_diff_path file_states
+       global current_diff_path file_states last_revert
        set ::cursorX $x
        set ::cursorY $y
        if {[info exists file_states($current_diff_path)]} {
@@ -3694,6 +3701,7 @@ proc popup_diff_menu {ctxm ctxmmg ctxmsm x y X Y} {
                tk_popup $ctxmsm $X $Y
        } else {
                set has_range [expr {[$::ui_diff tag nextrange sel 0.0] != {}}]
+               set u [mc "Undo Last Revert"]
                if {$::ui_index eq $::current_diff_side} {
                        set l [mc "Unstage Hunk From Commit"]
                        set h [mc "Revert Hunk"]
@@ -3739,12 +3747,20 @@ proc popup_diff_menu {ctxm ctxmmg ctxmsm x y X Y} {
                        }
                }
 
+               if {$last_revert eq {}} {
+                       set undo_state disabled
+               } else {
+                       set undo_state normal
+               }
+
                $ctxm entryconf $::ui_diff_applyhunk -state $s -label $l
                $ctxm entryconf $::ui_diff_applyline -state $s -label $t
                $ctxm entryconf $::ui_diff_revertline -state $revert_state \
                        -label $r
                $ctxm entryconf $::ui_diff_reverthunk -state $revert_state \
                        -label $h
+               $ctxm entryconf $::ui_diff_undorevert -state $undo_state \
+                       -label $u
 
                tk_popup $ctxm $X $Y
        }

diff --git a/lib/diff.tcl b/lib/diff.tcl
index 0659029632a000c4454c834cf9c579d85536b432..96288fcc332e0083a56fcbb9248bc10ac536388e 100644 (file)
--- a/lib/diff.tcl
+++ b/lib/diff.tcl
@@ -569,7 +569,7 @@ proc read_diff {fd conflict_size cont_info} {
 
 proc apply_or_revert_hunk {x y revert} {
        global current_diff_path current_diff_header current_diff_side
-       global ui_diff ui_index file_states
+       global ui_diff ui_index file_states last_revert last_revert_enc
 
        if {$current_diff_path eq {} || $current_diff_header eq {}} return
        if {![lock_index apply_hunk]} return
@@ -610,18 +610,25 @@ proc apply_or_revert_hunk {x y revert} {
                set e_lno end
        }
 
+       set wholepatch "$current_diff_header[$ui_diff get $s_lno $e_lno]"
+
        if {[catch {
                set enc [get_path_encoding $current_diff_path]
                set p [eval git_write $apply_cmd]
                fconfigure $p -translation binary -encoding $enc
-               puts -nonewline $p $current_diff_header
-               puts -nonewline $p [$ui_diff get $s_lno $e_lno]
+               puts -nonewline $p $wholepatch
                close $p} err]} {
                error_popup "$failed_msg\n\n$err"
                unlock_index
                return
        }
 
+       if {$revert} {
+               # Save a copy of this patch for undoing reverts.
+               set last_revert $wholepatch
+               set last_revert_enc $enc
+       }
+
        $ui_diff conf -state normal
        $ui_diff delete $s_lno $e_lno
        $ui_diff conf -state disabled
@@ -653,7 +660,7 @@ proc apply_or_revert_hunk {x y revert} {
 
 proc apply_or_revert_range_or_line {x y revert} {
        global current_diff_path current_diff_header current_diff_side
-       global ui_diff ui_index file_states
+       global ui_diff ui_index file_states last_revert
 
        set selected [$ui_diff tag nextrange sel 0.0]
 
@@ -852,5 +859,43 @@ proc apply_or_revert_range_or_line {x y revert} {
                return
        }
 
+       if {$revert} {
+               # Save a copy of this patch for undoing reverts.
+               set last_revert $current_diff_header$wholepatch
+               set last_revert_enc $enc
+       }
+
+       unlock_index
+}
+
+# Undo the last line/hunk reverted. When hunks and lines are reverted, a copy
+# of the diff applied is saved. Re-apply that diff to undo the revert.
+#
+# Right now, we only use a single variable to hold the copy, and not a
+# stack/deque for simplicity, so multiple undos are not possible. Maybe this
+# can be added if the need for something like this is felt in the future.
+proc undo_last_revert {} {
+       global last_revert current_diff_path current_diff_header
+       global last_revert_enc
+
+       if {$last_revert eq {}} return
+       if {![lock_index apply_hunk]} return
+
+       set apply_cmd {apply --whitespace=nowarn}
+       set failed_msg [mc "Failed to undo last revert."]
+
+       if {[catch {
+               set enc $last_revert_enc
+               set p [eval git_write $apply_cmd]
+               fconfigure $p -translation binary -encoding $enc
+               puts -nonewline $p $last_revert
+               close $p} err]} {
+               error_popup "$failed_msg\n\n$err"
+               unlock_index
+               return
+       }
+
+       set last_revert {}
+
        unlock_index
 }