git-gui: Refactor branch switch to support detached head

This is a major rewrite of the way we perform switching between
branches and the subsequent update of the working directory.  Like
core Git we now use a single code path to perform all changes: our
new checkout_op class.  We also use it for branch creation/update
as it integrates the tracking branch fetch process along with a
very basic merge (fast-forward and reset only currently).

Because some users have literally hundreds of local branches we
use the standard revision picker (with its branch filtering tool)
to select the local branch, rather than keeping all of the local
branches in the Branch menu.  The branch menu listing out all of
the available branches is simply not sane for those types of huge
repositories.

Users can now checkout a detached head by ticking off the option
in the checkout dialog.  This option is off by default for the
obvious reason, but it can be easily enabled for any local branch
by simply checking it.  We also detach the head if any non local
branch was selected, or if a revision expression was entered.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

1 files changed, 1 insertions, 168 deletions

diff --git a/lib/branch.tcl b/lib/branch.tcl
index a6e6921174..b948d926ae 100644
--- a/lib/branch.tcl
+++ b/lib/branch.tcl
@@ -2,7 +2,6 @@
 # Copyright (C) 2006, 2007 Shawn Pearce
 
 proc load_all_heads {} {
-	global all_heads
 	global some_heads_tracking
 
 	set rh refs/heads
@@ -16,7 +15,7 @@ proc load_all_heads {} {
 	}
 	close $fd
 
-	set all_heads [lsort $all_heads]
+	return [lsort $all_heads]
 }
 
 proc load_all_tags {} {
@@ -30,173 +29,7 @@ proc load_all_tags {} {
 	return $all_tags
 }
 
-proc populate_branch_menu {} {
-	global all_heads disable_on_lock
-
-	set m .mbar.branch
-	set last [$m index last]
-	for {set i 0} {$i <= $last} {incr i} {
-		if {[$m type $i] eq {separator}} {
-			$m delete $i last
-			set new_dol [list]
-			foreach a $disable_on_lock {
-				if {[lindex $a 0] ne $m || [lindex $a 2] < $i} {
-					lappend new_dol $a
-				}
-			}
-			set disable_on_lock $new_dol
-			break
-		}
-	}
-
-	if {$all_heads ne {}} {
-		$m add separator
-	}
-	foreach b $all_heads {
-		$m add radiobutton \
-			-label $b \
-			-command [list switch_branch $b] \
-			-variable current_branch \
-			-value $b
-		lappend disable_on_lock \
-			[list $m entryconf [$m index last] -state]
-	}
-}
-
 proc radio_selector {varname value args} {
 	upvar #0 $varname var
 	set var $value
 }
-
-proc switch_branch {new_branch} {
-	global HEAD commit_type current_branch repo_config
-
-	if {![lock_index switch]} return
-
-	# -- Our in memory state should match the repository.
-	#
-	repository_state curType curHEAD curMERGE_HEAD
-	if {[string match amend* $commit_type]
-		&& $curType eq {normal}
-		&& $curHEAD eq $HEAD} {
-	} elseif {$commit_type ne $curType || $HEAD ne $curHEAD} {
-		info_popup {Last scanned state does not match repository state.
-
-Another Git program has modified this repository since the last scan.  A rescan must be performed before the current branch can be changed.
-
-The rescan will be automatically started now.
-}
-		unlock_index
-		rescan {set ui_status_value {Ready.}}
-		return
-	}
-
-	# -- Don't do a pointless switch.
-	#
-	if {$current_branch eq $new_branch} {
-		unlock_index
-		return
-	}
-
-	if {$repo_config(gui.trustmtime) eq {true}} {
-		switch_branch_stage2 {} $new_branch
-	} else {
-		set ui_status_value {Refreshing file status...}
-		set cmd [list git update-index]
-		lappend cmd -q
-		lappend cmd --unmerged
-		lappend cmd --ignore-missing
-		lappend cmd --refresh
-		set fd_rf [open "| $cmd" r]
-		fconfigure $fd_rf -blocking 0 -translation binary
-		fileevent $fd_rf readable \
-			[list switch_branch_stage2 $fd_rf $new_branch]
-	}
-}
-
-proc switch_branch_stage2 {fd_rf new_branch} {
-	global ui_status_value HEAD
-
-	if {$fd_rf ne {}} {
-		read $fd_rf
-		if {![eof $fd_rf]} return
-		close $fd_rf
-	}
-
-	set ui_status_value "Updating working directory to '$new_branch'..."
-	set cmd [list git read-tree]
-	lappend cmd -m
-	lappend cmd -u
-	lappend cmd --exclude-per-directory=.gitignore
-	lappend cmd $HEAD
-	lappend cmd $new_branch
-	set fd_rt [open "| $cmd" r]
-	fconfigure $fd_rt -blocking 0 -translation binary
-	fileevent $fd_rt readable \
-		[list switch_branch_readtree_wait $fd_rt $new_branch]
-}
-
-proc switch_branch_readtree_wait {fd_rt new_branch} {
-	global selected_commit_type commit_type HEAD MERGE_HEAD PARENT
-	global current_branch
-	global ui_comm ui_status_value
-
-	# -- We never get interesting output on stdout; only stderr.
-	#
-	read $fd_rt
-	fconfigure $fd_rt -blocking 1
-	if {![eof $fd_rt]} {
-		fconfigure $fd_rt -blocking 0
-		return
-	}
-
-	# -- The working directory wasn't in sync with the index and
-	#    we'd have to overwrite something to make the switch. A
-	#    merge is required.
-	#
-	if {[catch {close $fd_rt} err]} {
-		regsub {^fatal: } $err {} err
-		warn_popup "File level merge required.
-
-$err
-
-Staying on branch '$current_branch'."
-		set ui_status_value "Aborted checkout of '$new_branch' (file level merging is required)."
-		unlock_index
-		return
-	}
-
-	# -- Update the symbolic ref.  Core git doesn't even check for failure
-	#    here, it Just Works(tm).  If it doesn't we are in some really ugly
-	#    state that is difficult to recover from within git-gui.
-	#
-	if {[catch {git symbolic-ref HEAD "refs/heads/$new_branch"} err]} {
-		error_popup "Failed to set current branch.
-
-This working directory is only partially switched.  We successfully updated your files, but failed to update an internal Git file.
-
-This should not have occurred.  [appname] will now close and give up.
-
-$err"
-		do_quit
-		return
-	}
-
-	# -- Update our repository state.  If we were previously in amend mode
-	#    we need to toss the current buffer and do a full rescan to update
-	#    our file lists.  If we weren't in amend mode our file lists are
-	#    accurate and we can avoid the rescan.
-	#
-	unlock_index
-	set selected_commit_type new
-	if {[string match amend* $commit_type]} {
-		$ui_comm delete 0.0 end
-		$ui_comm edit reset
-		$ui_comm edit modified false
-		rescan {set ui_status_value "Checked out branch '$current_branch'."}
-	} else {
-		repository_state commit_type HEAD MERGE_HEAD
-		set PARENT $HEAD
-		set ui_status_value "Checked out branch '$current_branch'."
-	}
-}