--- a/hgext3rd/topic/stack.py	Mon Sep 03 16:41:32 2018 +0200
+++ b/hgext3rd/topic/stack.py	Mon Sep 03 17:07:36 2018 +0200
@@ -239,11 +239,11 @@
         msg %= (branch, topic)
         raise error.ProgrammingError(msg)
     elif topic is not None:
-        prefix = 't'
+        prefix = 's'
         if topic not in repo.topics:
             raise error.Abort(_('cannot resolve "%s": no such topic found') % topic)
     elif branch is not None:
-        prefix = 'b'
+        prefix = 's'
     else:
         raise error.ProgrammingError('neither branch and topic specified (not defined yet)')
 

--- a/tests/test-evolve-topic.t	Mon Sep 03 16:41:32 2018 +0200
+++ b/tests/test-evolve-topic.t	Mon Sep 03 17:07:36 2018 +0200
@@ -80,11 +80,11 @@
   ### topic: foo (?)
   ### branch: default (?)
   ### target: default (branch)
-  t4@ add fff (current)
-  t3: add eee
-  t2: add ddd
-  t1: add ccc
-  t0^ add bbb (base)
+  s4@ add fff (current)
+  s3: add eee
+  s2: add ddd
+  s1: add ccc
+  s0^ add bbb (base)
   $ hg up 'desc(ddd)'
   0 files updated, 0 files merged, 2 files removed, 0 files unresolved
   $ echo ddd >> ddd
@@ -260,12 +260,12 @@
   $ hg stack
   ### topic: bar
   ### target: default (branch)
-  t5$ add jjj (unstable)
-  t4$ add iii (unstable)
-  t3$ add hhh (unstable)
-  t2$ add ggg (current unstable)
-  t1: add fff
-  t0^ add eee (base)
+  s5$ add jjj (unstable)
+  s4$ add iii (unstable)
+  s3$ add hhh (unstable)
+  s2$ add ggg (current unstable)
+  s1: add fff
+  s0^ add eee (base)
 
   $ hg prev
   0 files updated, 0 files merged, 1 files removed, 0 files unresolved

--- a/tests/test-stack-branch.t	Mon Sep 03 16:41:32 2018 +0200
+++ b/tests/test-stack-branch.t	Mon Sep 03 17:07:36 2018 +0200
@@ -56,8 +56,8 @@
   0 files updated, 0 files merged, 4 files removed, 0 files unresolved
   $ hg stack
   ### target: other (branch)
-  b2@ c_b (current)
-  b1: c_a
+  s2@ c_b (current)
+  s1: c_a
   $ hg phase --public 'branch("other")'
   $ hg up foo
   4 files updated, 0 files merged, 0 files removed, 0 files unresolved
@@ -71,18 +71,18 @@
   foo
   $ hg stack
   ### target: foo (branch)
-  b4@ c_f (current)
-  b3: c_e
-  b2: c_d
-  b1: c_c
-  b0^ c_b (base)
+  s4@ c_f (current)
+  s3: c_e
+  s2: c_d
+  s1: c_c
+  s0^ c_b (base)
   $ hg stack -v
   ### target: foo (branch)
-  b4(913c298d8b0a)@ c_f (current)
-  b3(4f2a69f6d380): c_e
-  b2(f61adbacd17a): c_d
-  b1(3e9313bc4b71): c_c
-  b0(4a04f1104a27)^ c_b (base)
+  s4(913c298d8b0a)@ c_f (current)
+  s3(4f2a69f6d380): c_e
+  s2(f61adbacd17a): c_d
+  s1(3e9313bc4b71): c_c
+  s0(4a04f1104a27)^ c_b (base)
 
 Test "t#" reference
 -------------------
@@ -127,20 +127,20 @@
   
   $ hg stack
   ### target: foo (branch)
-  b4$ c_f (unstable)
-  b3$ c_e (unstable)
-  b2@ c_d (current)
-  b1: c_c
-  b0^ c_b (base)
+  s4$ c_f (unstable)
+  s3$ c_e (unstable)
+  s2@ c_d (current)
+  s1: c_c
+  s0^ c_b (base)
   $ hg up b3
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg stack
   ### target: foo (branch)
-  b4$ c_f (unstable)
-  b3$ c_e (current unstable)
-  b2: c_d
-  b1: c_c
-  b0^ c_b (base)
+  s4$ c_f (unstable)
+  s3$ c_e (current unstable)
+  s2: c_d
+  s1: c_c
+  s0^ c_b (base)
   $ hg up b2
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
 
@@ -208,14 +208,14 @@
 
   $ hg stack
   ### target: foo (branch) (2 heads)
-  b6@ c_h (current)
-  b5: c_g
-  b2^ c_d (base)
-  b4: c_f
-  b3: c_e
-  b2: c_d
-  b1: c_c
-  b0^ c_b (base)
+  s6@ c_h (current)
+  s5: c_g
+  s2^ c_d (base)
+  s4: c_f
+  s3: c_e
+  s2: c_d
+  s1: c_c
+  s0^ c_b (base)
 
 Case with multiple heads on the topic with unstability involved
 ---------------------------------------------------------------
@@ -252,14 +252,14 @@
 
   $ hg stack
   ### target: foo (branch) (2 heads)
-  b6: c_h
-  b5: c_g
-  b2^ c_D (base current)
-  b4$ c_f (unstable)
-  b3$ c_e (unstable)
-  b2@ c_D (current)
-  b1: c_c
-  b0^ c_b (base)
+  s6: c_h
+  s5: c_g
+  s2^ c_D (base current)
+  s4$ c_f (unstable)
+  s3$ c_e (unstable)
+  s2@ c_D (current)
+  s1: c_c
+  s0^ c_b (base)
 
 Check that stack doesn't show draft changesets on a branch
 ----------------------------------------------------------
@@ -286,24 +286,24 @@
 
   $ hg stack
   ### target: foo (branch) (2 heads)
-  b6: c_h
-  b5: c_g
-  b2^ c_D (base current)
-  b4$ c_f (unstable)
-  b3$ c_e (unstable)
-  b2@ c_D (current)
-  b1: c_c
-  b0^ c_b (base)
+  s6: c_h
+  s5: c_g
+  s2^ c_D (base current)
+  s4$ c_f (unstable)
+  s3$ c_e (unstable)
+  s2@ c_D (current)
+  s1: c_c
+  s0^ c_b (base)
   $ hg phase --public b1
   $ hg stack
   ### target: foo (branch) (2 heads)
-  b5: c_h
-  b4: c_g
-  b1^ c_D (base current)
-  b3$ c_f (unstable)
-  b2$ c_e (unstable)
-  b1@ c_D (current)
-  b0^ c_c (base)
+  s5: c_h
+  s4: c_g
+  s1^ c_D (base current)
+  s3$ c_f (unstable)
+  s2$ c_e (unstable)
+  s1@ c_D (current)
+  s0^ c_c (base)
 
 Check that stack doesn't show changeset with a topic
 ----------------------------------------------------
@@ -312,7 +312,7 @@
   changed topic on 2 changes
   $ hg stack
   ### target: foo (branch)
-  b3$ c_f (unstable)
-  b2$ c_e (unstable)
-  b1@ c_D (current)
-  b0^ c_c (base)
+  s3$ c_f (unstable)
+  s2$ c_e (unstable)
+  s1@ c_D (current)
+  s0^ c_c (base)

--- a/tests/test-topic-fold.t	Mon Sep 03 16:41:32 2018 +0200
+++ b/tests/test-topic-fold.t	Mon Sep 03 17:07:36 2018 +0200
@@ -55,8 +55,8 @@
   $ hg stack
   ### topic: myfeature
   ### target: default (branch)
-  t1@ folded (current)
-  t0^ add ROOT (base)
+  s1@ folded (current)
+  s0^ add ROOT (base)
   $ logtopic
   @  3:4fd43e5bdc443dc8489edffac19bd8f93ccf1a5c
   |  topics: myfeature

--- a/tests/test-topic-rebase.t	Mon Sep 03 16:41:32 2018 +0200
+++ b/tests/test-topic-rebase.t	Mon Sep 03 17:07:36 2018 +0200
@@ -47,8 +47,8 @@
   $ hg stack
   ### topic: myfeature
   ### target: default (branch)
-  t1@ add feature1 (current)
-  t0^ add ROOT (base)
+  s1@ add feature1 (current)
+  s0^ add ROOT (base)
   $ logtopic
   @  1:39e7a938055e87615edf675c24a10997ff05bb06
   |  topics: myfeature
@@ -77,8 +77,8 @@
   $ hg stack
   ### topic: myfeature
   ### target: default (branch)
-  t1@ add feature1 (current)
-  t0^ add default (base)
+  s1@ add feature1 (current)
+  s0^ add default (base)
   $ logtopic
   @  3:fc6593661cf3256ba165cbccd6019ead17cc3726
   |  topics: myfeature
@@ -91,8 +91,8 @@
   $ hg stack
   ### topic: myfeature
   ### target: default (branch)
-  t1@ add feature1 (current)
-  t0^ add default (base)
+  s1@ add feature1 (current)
+  s0^ add default (base)
 
 Check that rebase keep the topic in case of merge conflict
 ----------------------------------------------------------
@@ -157,12 +157,12 @@
   $ hg stack
   ### topic: myotherfeature
   ### target: default (branch)
-  t1@ myotherfeature1 (current)
-  t0^ default3 (base)
+  s1@ myotherfeature1 (current)
+  s0^ default3 (base)
   $ hg update --rev 7
   0 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg stack
   ### topic: myotherfeature
   ### target: default (branch)
-  t1@ myotherfeature1 (current)
-  t0^ default3 (base)
+  s1@ myotherfeature1 (current)
+  s0^ default3 (base)

--- a/tests/test-topic-shelve.t	Mon Sep 03 16:41:32 2018 +0200
+++ b/tests/test-topic-shelve.t	Mon Sep 03 17:07:36 2018 +0200
@@ -26,7 +26,7 @@
   $ hg stack
   ### topic: testing-shelve
   ### target: default (branch)
-  t1@ First commit (current)
+  s1@ First commit (current)
 
 shelve test
 -----------
@@ -39,7 +39,7 @@
   $ hg stack
   ### topic: testing-shelve
   ### target: default (branch)
-  t1@ First commit (current)
+  s1@ First commit (current)
 
 unshelve test
 -------------
@@ -50,4 +50,4 @@
   $ hg stack
   ### topic: testing-shelve
   ### target: default (branch)
-  t1@ First commit (current)
+  s1@ First commit (current)

--- a/tests/test-topic-stack-complex.t	Mon Sep 03 16:41:32 2018 +0200
+++ b/tests/test-topic-stack-complex.t	Mon Sep 03 17:07:36 2018 +0200
@@ -42,10 +42,10 @@
   $ hg stack
   ### topic: foo
   ### target: default (branch)
-  t3@ Added e and f (current)
-  t2: Added c and d
-  t1: Added a and b
-  t0^ Added foo (base)
+  s3@ Added e and f (current)
+  s2: Added c and d
+  s1: Added a and b
+  s0^ Added foo (base)
   $ hg prev
   0 files updated, 0 files merged, 2 files removed, 0 files unresolved
   [2] Added c and d
@@ -86,11 +86,11 @@
   $ hg stack
   ### topic: foo
   ### target: default (branch)
-  t4$ Added e and f (unstable)
-  t3@ split2 (current)
-  t2: split1
-  t1: Added a and b
-  t0^ Added foo (base)
+  s4$ Added e and f (unstable)
+  s3@ split2 (current)
+  s2: split1
+  s1: Added a and b
+  s0^ Added foo (base)
 
   $ hg show work
   @  5cce (foo) split2
@@ -129,8 +129,8 @@
   $ hg stack
   ### topic: foo (2 heads)
   ### target: default (branch), 2 behind
-  t4$ Added e and f (unstable)
-  t3$ split2 (unstable)
-  t2@ split1 (current)
-  t1: Added a and b
-  t0^ Added foo (base)
+  s4$ Added e and f (unstable)
+  s3$ split2 (unstable)
+  s2@ split1 (current)
+  s1: Added a and b
+  s0^ Added foo (base)

--- a/tests/test-topic-stack-data.t	Mon Sep 03 16:41:32 2018 +0200
+++ b/tests/test-topic-stack-data.t	Mon Sep 03 17:07:36 2018 +0200
@@ -264,39 +264,39 @@
   $ hg stack bar
   ### topic: bar (2 heads)
   ### target: default (branch)
-  t5: add bar_c
-  t2^ add bar_b (base)
-  t4$ add bar_e (unstable)
-  t3: bar1_d
-  t2: add bar_b
-  t1: add bar_a
-  t0^ add base_e (base)
+  s5: add bar_c
+  s2^ add bar_b (base)
+  s4$ add bar_e (unstable)
+  s3: bar1_d
+  s2: add bar_b
+  s1: add bar_a
+  s0^ add base_e (base)
   $ hg stack bar -v
   ### topic: bar (2 heads)
   ### target: default (branch)
-  t5(9cbadf11b44d): add bar_c
-  t2(e555c7e8c767)^ add bar_b (base)
-  t4(a920412b5a05)$ add bar_e (unstable)
-  t3(6915989374b1): bar1_d
-  t2(e555c7e8c767): add bar_b
-  t1(a5c2b4e00bbf): add bar_a
-  t0(92f489a6251f)^ add base_e (base)
+  s5(9cbadf11b44d): add bar_c
+  s2(e555c7e8c767)^ add bar_b (base)
+  s4(a920412b5a05)$ add bar_e (unstable)
+  s3(6915989374b1): bar1_d
+  s2(e555c7e8c767): add bar_b
+  s1(a5c2b4e00bbf): add bar_a
+  s0(92f489a6251f)^ add base_e (base)
   $ hg stack baz
   ### topic: baz
   ### target: default (branch), 2 behind
-  t2: add baz_b
-  t1: add baz_a
-  t0^ add base_c (base)
+  s2: add baz_b
+  s1: add baz_a
+  s0^ add base_c (base)
   $ hg stack foo
   ### topic: foo
   ### target: lake (branch), ambiguous rebase destination - branch 'lake' has 2 heads
-  t2@ add foo_b (current)
-  t1: add foo_a
-  t0^ add lake_a (base)
+  s2@ add foo_b (current)
+  s1: add foo_a
+  s0^ add lake_a (base)
   $ hg stack fuz
   ### topic: fuz
   ### target: default (branch), 1 behind
-  t3$ add fuz_c (unstable)
-  t2$ add fuz_b (unstable)
-  t1: fuz1_a
-  t0^ add base_d (base)
+  s3$ add fuz_c (unstable)
+  s2$ add fuz_b (unstable)
+  s1: fuz1_a
+  s0^ add base_d (base)

--- a/tests/test-topic-stack.t	Mon Sep 03 16:41:32 2018 +0200
+++ b/tests/test-topic-stack.t	Mon Sep 03 17:07:36 2018 +0200
@@ -60,8 +60,8 @@
   $ hg topic --list
   ### topic: other
   ### target: default (branch)
-  t2@ c_b (current)
-  t1: c_a
+  s2@ c_b (current)
+  s1: c_a
   $ hg phase --public 'topic("other")'
   active topic 'other' is now empty
   (use 'hg topic --clear' to clear it if needed)
@@ -75,7 +75,7 @@
   ### topic: other
   ### target: default (branch)
   (stack is empty)
-  t0^ c_b (base current)
+  s0^ c_b (base current)
 
   $ hg up foo
   switching to topic foo
@@ -91,19 +91,19 @@
   $ hg stack
   ### topic: foo
   ### target: default (branch)
-  t4@ c_f (current)
-  t3: c_e
-  t2: c_d
-  t1: c_c
-  t0^ c_b (base)
+  s4@ c_f (current)
+  s3: c_e
+  s2: c_d
+  s1: c_c
+  s0^ c_b (base)
   $ hg stack -v
   ### topic: foo
   ### target: default (branch)
-  t4(6559e6d93aea)@ c_f (current)
-  t3(0f9ac936c87d): c_e
-  t2(e629654d7050): c_d
-  t1(8522f9e3fee9): c_c
-  t0(ea705abc4f51)^ c_b (base)
+  s4(6559e6d93aea)@ c_f (current)
+  s3(0f9ac936c87d): c_e
+  s2(e629654d7050): c_d
+  s1(8522f9e3fee9): c_c
+  s0(ea705abc4f51)^ c_b (base)
   $ hg stack -Tjson | python -m json.tool
   [
       {
@@ -213,21 +213,21 @@
   $ hg stack
   ### topic: foo
   ### target: default (branch)
-  t4@ c_f (current)
-  t3: c_e
-  t2: c_d
-  t1: c_c
-  t0^ c_b (base)
+  s4@ c_f (current)
+  s3: c_e
+  s2: c_d
+  s1: c_c
+  s0^ c_b (base)
   $ hg topics --config ui.strict=true
    * foo (4 changesets)
   $ hg stack --config ui.strict=true
   ### topic: foo
   ### target: default (branch)
-  t4@ c_f (current)
-  t3: c_e
-  t2: c_d
-  t1: c_c
-  t0^ c_b (base)
+  s4@ c_f (current)
+  s3: c_e
+  s2: c_d
+  s1: c_c
+  s0^ c_b (base)
 
 error case, nothing to list
 
@@ -235,7 +235,7 @@
   $ hg stack
   ### target: default (branch)
   (stack is empty)
-  b0^ c_f (base current)
+  s0^ c_f (base current)
 
 Test "t#" reference
 -------------------
@@ -287,29 +287,29 @@
   $ hg topic --list
   ### topic: foo
   ### target: default (branch)
-  t4$ c_f (unstable)
-  t3$ c_e (unstable)
-  t2@ c_d (current)
-  t1: c_c
-  t0^ c_b (base)
+  s4$ c_f (unstable)
+  s3$ c_e (unstable)
+  s2@ c_d (current)
+  s1: c_c
+  s0^ c_b (base)
   $ hg up s3
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ hg topic --list
   ### topic: foo
   ### target: default (branch)
-  t4$ c_f (unstable)
-  t3$ c_e (current unstable)
-  t2: c_d
-  t1: c_c
-  t0^ c_b (base)
+  s4$ c_f (unstable)
+  s3$ c_e (current unstable)
+  s2: c_d
+  s1: c_c
+  s0^ c_b (base)
   $ hg topic --list --color=debug
   [topic.stack.summary.topic|### topic: [topic.active|foo]]
   [topic.stack.summary.branches|### target: default (branch)]
-  [topic.stack.index topic.stack.index.unstable|t4][topic.stack.state topic.stack.state.unstable|$] [topic.stack.desc topic.stack.desc.unstable|c_f][topic.stack.state topic.stack.state.unstable| (unstable)]
-  [topic.stack.index topic.stack.index.current topic.stack.index.unstable|t3][topic.stack.state topic.stack.state.current topic.stack.state.unstable|$] [topic.stack.desc topic.stack.desc.current topic.stack.desc.unstable|c_e][topic.stack.state topic.stack.state.current topic.stack.state.unstable| (current unstable)]
-  [topic.stack.index topic.stack.index.clean|t2][topic.stack.state topic.stack.state.clean|:] [topic.stack.desc topic.stack.desc.clean|c_d]
-  [topic.stack.index topic.stack.index.clean|t1][topic.stack.state topic.stack.state.clean|:] [topic.stack.desc topic.stack.desc.clean|c_c]
-  [topic.stack.index topic.stack.index.base|t0][topic.stack.state topic.stack.state.base|^] [topic.stack.desc topic.stack.desc.base|c_b][topic.stack.state topic.stack.state.base| (base)]
+  [topic.stack.index topic.stack.index.unstable|s4][topic.stack.state topic.stack.state.unstable|$] [topic.stack.desc topic.stack.desc.unstable|c_f][topic.stack.state topic.stack.state.unstable| (unstable)]
+  [topic.stack.index topic.stack.index.current topic.stack.index.unstable|s3][topic.stack.state topic.stack.state.current topic.stack.state.unstable|$] [topic.stack.desc topic.stack.desc.current topic.stack.desc.unstable|c_e][topic.stack.state topic.stack.state.current topic.stack.state.unstable| (current unstable)]
+  [topic.stack.index topic.stack.index.clean|s2][topic.stack.state topic.stack.state.clean|:] [topic.stack.desc topic.stack.desc.clean|c_d]
+  [topic.stack.index topic.stack.index.clean|s1][topic.stack.state topic.stack.state.clean|:] [topic.stack.desc topic.stack.desc.clean|c_c]
+  [topic.stack.index topic.stack.index.base|s0][topic.stack.state topic.stack.state.base|^] [topic.stack.desc topic.stack.desc.base|c_b][topic.stack.state topic.stack.state.base| (base)]
   $ hg up s2
   1 files updated, 0 files merged, 1 files removed, 0 files unresolved
 
@@ -385,14 +385,14 @@
   $ hg top -l
   ### topic: foo (2 heads)
   ### target: default (branch)
-  t6@ c_h (current)
-  t5: c_g
-  t2^ c_d (base)
-  t4: c_f
-  t3: c_e
-  t2: c_d
-  t1: c_c
-  t0^ c_b (base)
+  s6@ c_h (current)
+  s5: c_g
+  s2^ c_d (base)
+  s4: c_f
+  s3: c_e
+  s2: c_d
+  s1: c_c
+  s0^ c_b (base)
 
 Case with multiple heads on the topic with unstability involved
 ---------------------------------------------------------------
@@ -430,14 +430,14 @@
   $ hg topic --list
   ### topic: foo (2 heads)
   ### target: default (branch)
-  t6: c_h
-  t5: c_g
-  t2^ c_D (base current)
-  t4$ c_f (unstable)
-  t3$ c_e (unstable)
-  t2@ c_D (current)
-  t1: c_c
-  t0^ c_b (base)
+  s6: c_h
+  s5: c_g
+  s2^ c_D (base current)
+  s4$ c_f (unstable)
+  s3$ c_e (unstable)
+  s2@ c_D (current)
+  s1: c_c
+  s0^ c_b (base)
 
 Trying to list non existing topic
   $ hg stack thisdoesnotexist
@@ -556,21 +556,21 @@
   $ hg stack
   ### topic: foobar
   ### target: default (branch), 3 behind
-  t2@ c_e (current)
+  s2@ c_e (current)
     ^ c_h
-  t1: c_D
-  t0^ c_c (base)
+  s1: c_D
+  s0^ c_c (base)
 
   $ hg stack foo
   ### topic: foo
   ### target: default (branch), ambiguous rebase destination - topic 'foo' has 3 heads
-  t4: c_f
+  s4: c_f
     ^ c_e
-  t3: c_h
-  t2: c_g
+  s3: c_h
+  s2: c_g
     ^ c_D
-  t1: c_c
-  t0^ c_b (base)
+  s1: c_c
+  s0^ c_b (base)
 
 case involving a merge
 ----------------------
@@ -646,24 +646,24 @@
   $ hg stack red
   ### topic: red
   ### target: default (branch), 6 behind
-  t5: c_H
+  s5: c_H
     ^ c_G
     ^ c_D
-  t4: c_C
-  t1^ c_B (base)
-  t3: c_F
-  t2: c_E
-  t1: c_B
-  t0^ c_A (base)
+  s4: c_C
+  s1^ c_B (base)
+  s3: c_F
+  s2: c_E
+  s1: c_B
+  s0^ c_A (base)
   $ hg stack blue
   ### topic: blue
   ### target: default (branch), ambiguous rebase destination - topic 'blue' has 3 heads
-  t3@ c_I (current)
+  s3@ c_I (current)
     ^ c_H
-  t2: c_D
+  s2: c_D
     ^ c_C
-  t1: c_G
-  t0^ c_F (base)
+  s1: c_G
+  s0^ c_F (base)
 
 Even with some obsolete and orphan changesets
 
@@ -712,24 +712,24 @@
   $ hg stack red
   ### topic: red
   ### target: default (branch), ambiguous rebase destination - topic 'red' has 3 heads
-  t5$ c_H (unstable)
+  s5$ c_H (unstable)
     ^ c_G
     ^ c_D
-  t4$ c_C (unstable)
-  t1^ c_B (base)
-  t3$ c_F (unstable)
-  t2$ c_E (unstable)
-  t1: c_B
-  t0^ c_A (base)
+  s4$ c_C (unstable)
+  s1^ c_B (base)
+  s3$ c_F (unstable)
+  s2$ c_E (unstable)
+  s1: c_B
+  s0^ c_A (base)
   $ hg stack blue
   ### topic: blue
   ### target: default (branch), ambiguous rebase destination - topic 'blue' has 3 heads
-  t3$ c_I (unstable)
+  s3$ c_I (unstable)
     ^ c_H
-  t2$ c_G (unstable)
+  s2$ c_G (unstable)
     ^ c_F
-  t1$ c_D (current unstable)
-  t0^ c_C (base unstable)
+  s1$ c_D (current unstable)
+  s0^ c_C (base unstable)
 
 more obsolescence
 
@@ -786,24 +786,24 @@
   $ hg stack red
   ### topic: red
   ### target: default (branch), ambiguous rebase destination - topic 'red' has 3 heads
-  t5$ c_H (unstable)
+  s5$ c_H (unstable)
     ^ c_G
     ^ c_D
-  t4$ c_F (unstable)
-  t3$ c_E (unstable)
-  t1^ c_B (base)
-  t2$ c_C (unstable)
-  t1: c_B
-  t0^ c_A (base)
+  s4$ c_F (unstable)
+  s3$ c_E (unstable)
+  s1^ c_B (base)
+  s2$ c_C (unstable)
+  s1: c_B
+  s0^ c_A (base)
   $ hg stack blue
   ### topic: blue
   ### target: default (branch), ambiguous rebase destination - topic 'blue' has 3 heads
-  t3$ c_I (unstable)
+  s3$ c_I (unstable)
     ^ c_H
-  t2$ c_G (unstable)
+  s2$ c_G (unstable)
     ^ c_F
-  t1$ c_D (current unstable)
-  t0^ c_C (base unstable)
+  s1$ c_D (current unstable)
+  s0^ c_C (base unstable)
 
 Test stack behavior with a split
 --------------------------------
@@ -820,10 +820,10 @@
   $ hg stack
   ### topic: blue
   ### target: default (branch)
-  t3: c_I
-  t2: c_G
-  t1@ c_D (current)
-  t0^ c_A (base)
+  s3: c_I
+  s2: c_G
+  s1@ c_D (current)
+  s0^ c_A (base)
 
 making a split
 (first get something to split)
@@ -842,10 +842,10 @@
   $ hg stack
   ### topic: blue
   ### target: default (branch)
-  t3$ c_I (unstable)
-  t2@ c_G (current)
-  t1: c_D
-  t0^ c_A (base)
+  s3$ c_I (unstable)
+  s2@ c_G (current)
+  s1: c_D
+  s0^ c_A (base)
   $ hg --config extensions.evolve=  --config ui.interactive=yes split << EOF
   > y
   > y
@@ -922,8 +922,8 @@
   $ hg stack
   ### topic: blue
   ### target: default (branch)
-  t4$ c_I (unstable)
-  t3@ c_G (current)
-  t2: c_G
-  t1: c_D
-  t0^ c_A (base)
+  s4$ c_I (unstable)
+  s3@ c_G (current)
+  s2: c_G
+  s1: c_D
+  s0^ c_A (base)

--- a/tests/test-topic-tutorial.t	Mon Sep 03 16:41:32 2018 +0200
+++ b/tests/test-topic-tutorial.t	Mon Sep 03 17:07:36 2018 +0200
@@ -252,9 +252,9 @@
   $ hg stack
   ### topic: food
   ### target: default (branch)
-  t2@ adding fruits (current)
-  t1: adding condiments
-  t0^ Shopping list (base)
+  s2@ adding fruits (current)
+  s1: adding condiments
+  s0^ Shopping list (base)
 
 The topic deactivates when we update away from it:
 
@@ -614,7 +614,7 @@
   ### topic: food
   ### target: default (branch)
   (stack is empty)
-  t0^ adding fruits (base current)
+  s0^ adding fruits (base current)
 
   $ hg log --graph
   @  changeset:   5:2d50db8b5b4c
@@ -791,9 +791,9 @@
   $ hg stack
   ### topic: drinks
   ### target: default (branch)
-  t2@ Adding orange juice (current)
-  t1: Adding apple juice
-  t0^ adding fruits (base)
+  s2@ Adding orange juice (current)
+  s1: Adding apple juice
+  s0^ adding fruits (base)
 
   $ hg update tools
   switching to topic tools
@@ -802,10 +802,10 @@
   $ hg stack
   ### topic: tools
   ### target: default (branch)
-  t3@ Adding drill (current)
-  t2: Adding saw
-  t1: Adding hammer
-  t0^ adding fruits (base)
+  s3@ Adding drill (current)
+  s2: Adding saw
+  s1: Adding hammer
+  s0^ adding fruits (base)
 
 They are seen as independent branches by Mercurial. No rebase or merge
 between them will be attempted by default:
@@ -1121,10 +1121,10 @@
   $ hg stack
   ### topic: tools
   ### target: default (branch), 2 behind
-  t3@ Adding drill (current)
-  t2: Adding saw
-  t1: Adding hammer
-  t0^ add a pair of shoes (base)
+  s3@ Adding drill (current)
+  s2: Adding saw
+  s1: Adding hammer
+  s0^ add a pair of shoes (base)
 
 Working Within Your Stack
 ===========================
@@ -1140,10 +1140,10 @@
   $ hg stack
   ### topic: tools
   ### target: default (branch), 2 behind
-  t3@ Adding drill (current)
-  t2: Adding saw
-  t1: Adding hammer
-  t0^ add a pair of shoes (base)
+  s3@ Adding drill (current)
+  s2: Adding saw
+  s1: Adding hammer
+  s0^ add a pair of shoes (base)
 
 You can navigate in your current stack with `previous` and `next`.
 
@@ -1156,10 +1156,10 @@
   $ hg stack
   ### topic: tools
   ### target: default (branch), 2 behind
-  t3: Adding drill
-  t2@ Adding saw (current)
-  t1: Adding hammer
-  t0^ add a pair of shoes (base)
+  s3: Adding drill
+  s2@ Adding saw (current)
+  s1: Adding hammer
+  s0^ add a pair of shoes (base)
 
 `next` will move you forward to the topic head.
 
@@ -1170,10 +1170,10 @@
   $ hg stack
   ### topic: tools
   ### target: default (branch), 2 behind
-  t3@ Adding drill (current)
-  t2: Adding saw
-  t1: Adding hammer
-  t0^ add a pair of shoes (base)
+  s3@ Adding drill (current)
+  s2: Adding saw
+  s1: Adding hammer
+  s0^ add a pair of shoes (base)
 
 You can also directly jump to a changeset within your stack with the revset `t#`.
 
@@ -1183,10 +1183,10 @@
   $ hg stack
   ### topic: tools
   ### target: default (branch), 2 behind
-  t3: Adding drill
-  t2: Adding saw
-  t1@ Adding hammer (current)
-  t0^ add a pair of shoes (base)
+  s3: Adding drill
+  s2: Adding saw
+  s1@ Adding hammer (current)
+  s0^ add a pair of shoes (base)
 
 Editing your work mid-stack
 ---------------------------
@@ -1196,10 +1196,10 @@
   $ hg stack
   ### topic: tools
   ### target: default (branch), 2 behind
-  t3: Adding drill
-  t2: Adding saw
-  t1@ Adding hammer (current)
-  t0^ add a pair of shoes (base)
+  s3: Adding drill
+  s2: Adding saw
+  s1@ Adding hammer (current)
+  s0^ add a pair of shoes (base)
 
   $ hg amend -m "Adding hammer to the shopping list"
   2 new orphan changesets
@@ -1358,10 +1358,10 @@
   $ hg stack
   ### topic: tools
   ### target: default (branch), 2 behind
-  t3$ Adding drill (unstable)
-  t2$ Adding saw (unstable)
-  t1@ Adding hammer to the shopping list (current)
-  t0^ add a pair of shoes (base)
+  s3$ Adding drill (unstable)
+  s2$ Adding saw (unstable)
+  s1@ Adding hammer to the shopping list (current)
+  s0^ add a pair of shoes (base)
 
 It's easy to stabilize the situation, `next` has an `--evolve` option.  It will
 do the necessary relocation of `s2` and `s3` over the new `s1` without having
@@ -1375,10 +1375,10 @@
   $ hg stack
   ### topic: tools
   ### target: default (branch), 2 behind
-  t3$ Adding drill (unstable)
-  t2@ Adding saw (current)
-  t1: Adding hammer to the shopping list
-  t0^ add a pair of shoes (base)
+  s3$ Adding drill (unstable)
+  s2@ Adding saw (current)
+  s1: Adding hammer to the shopping list
+  s0^ add a pair of shoes (base)
 
 One more to go:
 
@@ -1390,10 +1390,10 @@
   $ hg stack
   ### topic: tools
   ### target: default (branch), 2 behind
-  t3@ Adding drill (current)
-  t2: Adding saw
-  t1: Adding hammer to the shopping list
-  t0^ add a pair of shoes (base)
+  s3@ Adding drill (current)
+  s2: Adding saw
+  s1: Adding hammer to the shopping list
+  s0^ add a pair of shoes (base)
 
 Let's take a look at `hg log` once again:
 
@@ -1533,12 +1533,12 @@
   $ hg stack
   ### topic: tools (2 heads)
   ### target: default (branch), 2 behind
-  t4: Adding drill
-  t3: Adding saw
-  t1^ Adding hammer to the shopping list (base)
-  t2@ Adding nails (current)
-  t1: Adding hammer to the shopping list
-  t0^ add a pair of shoes (base)
+  s4: Adding drill
+  s3: Adding saw
+  s1^ Adding hammer to the shopping list (base)
+  s2@ Adding nails (current)
+  s1: Adding hammer to the shopping list
+  s0^ add a pair of shoes (base)
 
 Solving this situation is easy with a topic: use merge or rebase.
 Merge within a multi-headed stack will use the other topic head as
@@ -1783,11 +1783,11 @@
   $ hg stack
   ### topic: tools
   ### target: default (branch), 2 behind
-  t4@ Adding drill (current)
-  t3: Adding saw
-  t2: Adding nails
-  t1: Adding hammer to the shopping list
-  t0^ add a pair of shoes (base)
+  s4@ Adding drill (current)
+  s3: Adding saw
+  s2: Adding nails
+  s1: Adding hammer to the shopping list
+  s0^ add a pair of shoes (base)
 
 Collaborating through a non-publishing server
 =============================================
@@ -1858,11 +1858,11 @@
   $ hg stack
   ### topic: tools
   ### target: default (branch), 2 behind
-  t4@ Adding drill (current)
-  t3: Adding saw
-  t2: Adding nails
-  t1: Adding hammer to the shopping list
-  t0^ add a pair of shoes (base)
+  s4@ Adding drill (current)
+  s3: Adding saw
+  s2: Adding nails
+  s1: Adding hammer to the shopping list
+  s0^ add a pair of shoes (base)
 
 We can also add new changesets and share them:
 
@@ -1898,9 +1898,9 @@
   $ hg stack
   ### topic: tools
   ### target: default (branch), 2 behind
-  t5@ Adding screws (current)
-  t4: Adding drill
-  t3: Adding saw
-  t2: Adding nails
-  t1: Adding hammer to the shopping list
-  t0^ add a pair of shoes (base)
+  s5@ Adding screws (current)
+  s4: Adding drill
+  s3: Adding saw
+  s2: Adding nails
+  s1: Adding hammer to the shopping list
+  s0^ add a pair of shoes (base)

--- a/tests/test-topic.t	Mon Sep 03 16:41:32 2018 +0200
+++ b/tests/test-topic.t	Mon Sep 03 17:07:36 2018 +0200
@@ -273,7 +273,7 @@
   ### topic: narf
   ### target: default (branch)
   (stack is empty)
-  t0^ Add file delta (base current)
+  s0^ Add file delta (base current)
 
 Add commits to topic
 
@@ -802,8 +802,8 @@
   $ hg stack
   ### topic: fran
   ### target: default (branch), ambiguous rebase destination - branch 'default' has 2 heads
-  t1@ start on fran (current)
-  t0^ Add file delta (base)
+  s1@ start on fran (current)
+  s0^ Add file delta (base)
 
   $ hg up s0
   preserving the current topic 'fran'
@@ -814,8 +814,8 @@
   $ hg stack
   ### topic: fran
   ### target: default (branch), ambiguous rebase destination - branch 'default' has 2 heads
-  t1: start on fran
-  t0^ Add file delta (base current)
+  s1: start on fran
+  s0^ Add file delta (base current)
 
   $ hg topics --age
    * fran (1970-01-01 by test)