Remember repository that was branched off from for merging and editing

With this commit, "morph branch" and "morph checkout" remember the
repository that was branched off from (the "branch root") in a special
file called

  $workspace/$branch/.morph-system-branch/branch-root

This information is later used when checking out individual
repositories using "morph edit" instead of using the previously
hard-coded "$workspace/$branch/morphs" repository as the branch
root.

This commit also updates the "morph merge" code to handle repositories
specified with aliases or as full URLs in the same way "morph checkout"
does.

All affected tests are updated.

9 files changed, 15 insertions, 9 deletions

diff --git a/tests.branching/branch-creates-new-system-branch-not-from-master.stdout b/tests.branching/branch-creates-new-system-branch-not-from-master.stdout
index af1ad6cd..7dc55cc0 100644
--- a/tests.branching/branch-creates-new-system-branch-not-from-master.stdout
+++ b/tests.branching/branch-creates-new-system-branch-not-from-master.stdout
@@ -9,6 +9,7 @@ d ./newbranch
 d ./newbranch/.morph-system-branch
 d ./newbranch/morphs
 d ./newbranch/morphs/.git
+f ./newbranch/.morph-system-branch/branch-root
 f ./newbranch/morphs/hello-stratum.morph
 f ./newbranch/morphs/hello-system.morph
 f ./newbranch/morphs/this.is.alfred
diff --git a/tests.branching/branch-creates-new-system-branch.stdout b/tests.branching/branch-creates-new-system-branch.stdout
index e22ef30b..c37fb0e4 100644
--- a/tests.branching/branch-creates-new-system-branch.stdout
+++ b/tests.branching/branch-creates-new-system-branch.stdout
@@ -9,6 +9,7 @@ d ./newbranch
 d ./newbranch/.morph-system-branch
 d ./newbranch/morphs
 d ./newbranch/morphs/.git
+f ./newbranch/.morph-system-branch/branch-root
 f ./newbranch/morphs/hello-stratum.morph
 f ./newbranch/morphs/hello-system.morph
 Current branches:
diff --git a/tests.branching/checkout-existing-branch.stdout b/tests.branching/checkout-existing-branch.stdout
index 7ac4a149..1af2900c 100644
--- a/tests.branching/checkout-existing-branch.stdout
+++ b/tests.branching/checkout-existing-branch.stdout
@@ -9,6 +9,7 @@ d ./master
 d ./master/.morph-system-branch
 d ./master/baserock:morphs
 d ./master/baserock:morphs/.git
+f ./master/.morph-system-branch/branch-root
 f ./master/baserock:morphs/hello-stratum.morph
 f ./master/baserock:morphs/hello-system.morph
 Current branches:
diff --git a/tests.branching/checkout-non-aliased-repos.stdout b/tests.branching/checkout-non-aliased-repos.stdout
index 75dcd63d..872d74aa 100644
--- a/tests.branching/checkout-non-aliased-repos.stdout
+++ b/tests.branching/checkout-non-aliased-repos.stdout
@@ -12,6 +12,7 @@ d ./master/TEMP_DIR
 d ./master/DATADIR
 d ./master/DATADIR/morphs
 d ./master/DATADIR/morphs/.git
+f ./master/.morph-system-branch/branch-root
 f ./master/DATADIR/morphs/hello-stratum.morph
 f ./master/DATADIR/morphs/hello-system.morph
 Current branches of repo with suffix:
@@ -30,6 +31,7 @@ d ./master/TEMP_DIR
 d ./master/DATADIR
 d ./master/DATADIR/morphs
 d ./master/DATADIR/morphs/.git
+f ./master/.morph-system-branch/branch-root
 f ./master/DATADIR/morphs/hello-stratum.morph
 f ./master/DATADIR/morphs/hello-system.morph
 Current branches of repo without suffix:
diff --git a/tests.branching/edit-checkouts-existing-chunk.script b/tests.branching/edit-checkouts-existing-chunk.script
index b8480a5b..1c8e66cd 100755
--- a/tests.branching/edit-checkouts-existing-chunk.script
+++ b/tests.branching/edit-checkouts-existing-chunk.script
@@ -33,7 +33,7 @@ echo "Current branches, morphs:"
 "$SRCDIR/scripts/run-git-in" "$DATADIR/workspace/alfred/baserock:morphs" branch
 
 echo "Current branches, hello:"
-"$SRCDIR/scripts/run-git-in" "$DATADIR/workspace/alfred/hello" branch
+"$SRCDIR/scripts/run-git-in" "$DATADIR/workspace/alfred/baserock:hello" branch
 
 echo "Files in hello:"
-ls "$DATADIR/workspace/alfred/hello"
+ls "$DATADIR/workspace/alfred/baserock:hello"
diff --git a/tests.branching/edit-clones-chunk.script b/tests.branching/edit-clones-chunk.script
index 20f62a27..d5e117cb 100755
--- a/tests.branching/edit-clones-chunk.script
+++ b/tests.branching/edit-clones-chunk.script
@@ -38,9 +38,10 @@ echo "Current origin, morphs:"
         sed 's,\(TMP/workspace/\.morph/cache/gits/file_\).*_,\1,g'
 
 echo "Current branches, hello:"
-"$SRCDIR/scripts/run-git-in" "$DATADIR/workspace/newbranch/hello" branch
+"$SRCDIR/scripts/run-git-in" \
+    "$DATADIR/workspace/newbranch/baserock:hello" branch
 
 echo "Current origin, hello:"
-"$SRCDIR/scripts/run-git-in" "$DATADIR/workspace/newbranch/hello" \
+"$SRCDIR/scripts/run-git-in" "$DATADIR/workspace/newbranch/baserock:hello" \
     remote show origin | \
         sed 's,\(TMP/workspace/\.morph/cache/gits/file_\).*_,\1,g'
diff --git a/tests.branching/edit-uses-ref-from-stratum.script b/tests.branching/edit-uses-ref-from-stratum.script
index ce3e0ccc..f2276f3b 100755
--- a/tests.branching/edit-uses-ref-from-stratum.script
+++ b/tests.branching/edit-uses-ref-from-stratum.script
@@ -29,5 +29,5 @@ cd "$DATADIR/workspace"
 cd newbranch/morphs
 "$SRCDIR/scripts/test-morph" edit baserock:hello
 
-cd ../hello
+cd ../baserock:hello
 git branch
diff --git a/tests.branching/merge-explicitly-named-repos.script b/tests.branching/merge-explicitly-named-repos.script
index 9052cd31..5a0953a7 100755
--- a/tests.branching/merge-explicitly-named-repos.script
+++ b/tests.branching/merge-explicitly-named-repos.script
@@ -29,7 +29,7 @@ cd "$DATADIR/workspace"
 # Make a change to a chunk.
 cd newbranch/morphs
 "$SRCDIR/scripts/test-morph" edit baserock:hello master
-cd ../hello
+cd ../baserock:hello
 touch newfile.txt
 git add newfile.txt
 git commit -m foo --quiet
@@ -42,7 +42,7 @@ cd otherbranch/morphs
 "$SRCDIR/scripts/test-morph" merge newbranch baserock:hello
 
 # Check results.
-cd ../hello
+cd ../baserock:hello
 git status --short # make sure all changes are committed
 ls newfile.txt # make sure the new file is there
 
diff --git a/tests.branching/workflow.script b/tests.branching/workflow.script
index 64326e4a..59c7b152 100755
--- a/tests.branching/workflow.script
+++ b/tests.branching/workflow.script
@@ -26,7 +26,7 @@ cd "$DATADIR/workspace"
 "$SRCDIR/scripts/test-morph" branch me/readme-fix
 cd me/readme-fix/morphs
 "$SRCDIR/scripts/test-morph" edit baserock:hello master
-cd ../hello
+cd ../baserock:hello
 echo > README yoyoyo
 git add README
 git commit -m "Fix README, yo!" --quiet
@@ -35,5 +35,5 @@ cd "$DATADIR/workspace"
 "$SRCDIR/scripts/test-morph" checkout baserock:morphs master
 cd master/baserock:morphs
 "$SRCDIR/scripts/test-morph" edit baserock:hello master
-"$SRCDIR/scripts/test-morph" merge me/readme-fix hello
+"$SRCDIR/scripts/test-morph" merge me/readme-fix baserock:hello