[PATCH v4] git-prompt: make colourization consistent

[Joakim Petersen <joak-pet@online.no>]

The short upstream state indicator inherits the colour of the last short
state indicator before it (if there is one), and the sparsity state
indicator inherits this colour as well. Make the colourization of these
state indicators consistent by making all colourized indicators clear
their own colour.

As of 0ec7c23cdc6 (git-prompt: make upstream state indicator location
consistent, 2022-02-27), colourization in the output of __git_ps1 has
changed such that the short upstream state indicator inherits the colour
of the last short state indicator before it (if there is one), while
before this change it was white/the default text colour. Some examples
to illustrate this behaviour (assuming all indicators are enabled and
colourization is on):
 * If there is something in the stash, both the '$' and the short
   upstream state indicator following it will be blue.
 * If the local tree has new, untracked files and there is nothing in
   the stash, both the '%' and the    short upstream state indicator
   will be red.
 * If all local changes are added to the index and the stash is empty,
   both the '+' and the short upstream state indicator following it will
   be green.
 * If the local tree is clean and there is nothing in the stash, the
   short upstream state indicator will be white/${default text colour}.

This appears to be an unintended side-effect of the change, and makes
little sense semantically (e.g. why is it bad to be in sync with
upstream when you have uncommitted local changes?). The cause of the
change is that previously, the short upstream state indicator appeared
immediately after the rebase/revert/bisect/merge state indicator (note
the position of $p in $gitstring):

	local f="$h$w$i$s$u"
	local gitstring="$c$b${f:+$z$f}${sparse}$r$p"
	
Said indicator is prepended with the clear colour code, and the short
upstream state indicator is thus also uncoloured. Now, the short
upstream state indicator follows the sequence of colourized indicators,
without any clearing of colour (again note the position of $p, now in
$f):

	local f="$h$w$i$s$u$p"
	local gitstring="$c$b${f:+$z$f}${sparse}$r${upstream}"

If the user is in a sparse checkout, the sparsity state indicator
follows a similar pattern to the short upstream state indicator.
However, clearing colour of the colourized indicators changes how the
sparsity state indicator is colourized , as it currently inherits (and
before the change referenced also inherited) the colour of the last
short state indicator before it. Reading the commit message of the
change that introduced the sparsity state indicator, afda36dbf3b
(git-prompt: include sparsity state as well, 2020-06-21), it appears
this colourization also was unintended, so clearing the colour for said
indicator further increases consistency.

Colouring of $c was made dependent on it not being empty, as it is no
longer being used to colour the branch name. Removal of $b's prefix was
moved to before the colourization so it gets cleared properly now that
colour codes are inserted into it.

Due to colour clearing being moved into the variables for each coloured
indicator, the tests for the coloured Bash prompt had to be changed:
 * All colour tests now have the colour codes around the expected
   content of the expanded $__git_ps1_branch_name variable instead of
   the unexpanded variable in the string.
 * The test with two indicators had a clear-colour code inserted after
   the symbol for the first indicator, since all indicators clear their
   own colours now.

Signed-off-by: Joakim Petersen <joak-pet@online.no>
---
Changes since v3:
 * All colourized variables now also clear their own colour.
 * Variables are only coloured if they are not empty, except $b (branch
   name), which is not an optional indicator.
 * Updated tests to reflect the new colourization behaviour.
 * Fixed a mistake in two of the examples; the stash indicator is the
   last of the short state indicators preceding the short upstream state
   indicator.

Range-diff against v3:
1:  0e107d0496 < -:  ---------- git-prompt: make colourization consistent
-:  ---------- > 1:  98ce78ddc5 git-prompt: make colourization consistent

 contrib/completion/git-prompt.sh | 20 +++++++++++---------
 t/t9903-bash-prompt.sh           | 18 +++++++++---------
 2 files changed, 20 insertions(+), 18 deletions(-)

diff --git a/contrib/completion/git-prompt.sh b/contrib/completion/git-prompt.sh
index 87b2b916c0..32bb98bb8d 100644
--- a/contrib/completion/git-prompt.sh
+++ b/contrib/completion/git-prompt.sh
@@ -245,7 +245,8 @@ __git_ps1_show_upstream ()
 
 # Helper function that is meant to be called from __git_ps1.  It
 # injects color codes into the appropriate gitstring variables used
-# to build a gitstring.
+# to build a gitstring. Colored variables are responsible for clearing
+# their own color.
 __git_ps1_colorize_gitstring ()
 {
 	if [[ -n ${ZSH_VERSION-} ]]; then
@@ -271,22 +272,23 @@ __git_ps1_colorize_gitstring ()
 	else
 		branch_color="$bad_color"
 	fi
-	c="$branch_color$c"
+	if [ -n "$c" ]; then
+		c="$branch_color$c$c_clear"
+	fi
+	b="$branch_color$b$c_clear"
 
-	z="$c_clear$z"
 	if [ "$w" = "*" ]; then
-		w="$bad_color$w"
+		w="$bad_color$w$c_clear"
 	fi
 	if [ -n "$i" ]; then
-		i="$ok_color$i"
+		i="$ok_color$i$c_clear"
 	fi
 	if [ -n "$s" ]; then
-		s="$flags_color$s"
+		s="$flags_color$s$c_clear"
 	fi
 	if [ -n "$u" ]; then
-		u="$bad_color$u"
+		u="$bad_color$u$c_clear"
 	fi
-	r="$c_clear$r"
 }
 
 # Helper function to read the first line of a file into a variable.
@@ -554,6 +556,7 @@ __git_ps1 ()
 		fi
 	fi
 
+	b=${b##refs/heads/}
 	local z="${GIT_PS1_STATESEPARATOR-" "}"
 
 	# NO color option unless in PROMPT_COMMAND mode or it's Zsh
@@ -563,7 +566,6 @@ __git_ps1 ()
 		fi
 	fi
 
-	b=${b##refs/heads/}
 	if [ $pcmode = yes ] && [ $ps1_expanded = yes ]; then
 		__git_ps1_branch_name=$b
 		b="\${__git_ps1_branch_name}"
diff --git a/t/t9903-bash-prompt.sh b/t/t9903-bash-prompt.sh
index bbd513bab0..abd82eec35 100755
--- a/t/t9903-bash-prompt.sh
+++ b/t/t9903-bash-prompt.sh
@@ -541,7 +541,7 @@ test_expect_success 'prompt - pc mode' '
 '
 
 test_expect_success 'prompt - bash color pc mode - branch name' '
-	printf "BEFORE: (${c_green}\${__git_ps1_branch_name}${c_clear}):AFTER\\nmain" >expected &&
+	printf "BEFORE: (\${__git_ps1_branch_name}):AFTER\\n${c_green}main${c_clear}" >expected &&
 	(
 		GIT_PS1_SHOWCOLORHINTS=y &&
 		__git_ps1 "BEFORE:" ":AFTER" >"$actual" &&
@@ -551,7 +551,7 @@ test_expect_success 'prompt - bash color pc mode - branch name' '
 '
 
 test_expect_success 'prompt - bash color pc mode - detached head' '
-	printf "BEFORE: (${c_red}\${__git_ps1_branch_name}${c_clear}):AFTER\\n(%s...)" $(git log -1 --format="%h" b1^) >expected &&
+	printf "BEFORE: (\${__git_ps1_branch_name}):AFTER\\n${c_red}(%s...)"${c_clear} $(git log -1 --format="%h" b1^) >expected &&
 	git checkout b1^ &&
 	test_when_finished "git checkout main" &&
 	(
@@ -563,7 +563,7 @@ test_expect_success 'prompt - bash color pc mode - detached head' '
 '
 
 test_expect_success 'prompt - bash color pc mode - dirty status indicator - dirty worktree' '
-	printf "BEFORE: (${c_green}\${__git_ps1_branch_name}${c_clear} ${c_red}*${c_clear}):AFTER\\nmain" >expected &&
+	printf "BEFORE: (\${__git_ps1_branch_name} ${c_red}*${c_clear}):AFTER\\n${c_green}main${c_clear}" >expected &&
 	echo "dirty" >file &&
 	test_when_finished "git reset --hard" &&
 	(
@@ -576,7 +576,7 @@ test_expect_success 'prompt - bash color pc mode - dirty status indicator - dirt
 '
 
 test_expect_success 'prompt - bash color pc mode - dirty status indicator - dirty index' '
-	printf "BEFORE: (${c_green}\${__git_ps1_branch_name}${c_clear} ${c_green}+${c_clear}):AFTER\\nmain" >expected &&
+	printf "BEFORE: (\${__git_ps1_branch_name} ${c_green}+${c_clear}):AFTER\\n${c_green}main${c_clear}" >expected &&
 	echo "dirty" >file &&
 	test_when_finished "git reset --hard" &&
 	git add -u &&
@@ -590,7 +590,7 @@ test_expect_success 'prompt - bash color pc mode - dirty status indicator - dirt
 '
 
 test_expect_success 'prompt - bash color pc mode - dirty status indicator - dirty index and worktree' '
-	printf "BEFORE: (${c_green}\${__git_ps1_branch_name}${c_clear} ${c_red}*${c_green}+${c_clear}):AFTER\\nmain" >expected &&
+	printf "BEFORE: (\${__git_ps1_branch_name} ${c_red}*${c_clear}${c_green}+${c_clear}):AFTER\\n${c_green}main${c_clear}" >expected &&
 	echo "dirty index" >file &&
 	test_when_finished "git reset --hard" &&
 	git add -u &&
@@ -605,7 +605,7 @@ test_expect_success 'prompt - bash color pc mode - dirty status indicator - dirt
 '
 
 test_expect_success 'prompt - bash color pc mode - dirty status indicator - before root commit' '
-	printf "BEFORE: (${c_green}\${__git_ps1_branch_name}${c_clear} ${c_green}#${c_clear}):AFTER\\nmain" >expected &&
+	printf "BEFORE: (\${__git_ps1_branch_name} ${c_green}#${c_clear}):AFTER\\n${c_green}main${c_clear}" >expected &&
 	(
 		GIT_PS1_SHOWDIRTYSTATE=y &&
 		GIT_PS1_SHOWCOLORHINTS=y &&
@@ -617,7 +617,7 @@ test_expect_success 'prompt - bash color pc mode - dirty status indicator - befo
 '
 
 test_expect_success 'prompt - bash color pc mode - inside .git directory' '
-	printf "BEFORE: (${c_green}\${__git_ps1_branch_name}${c_clear}):AFTER\\nGIT_DIR!" >expected &&
+	printf "BEFORE: (\${__git_ps1_branch_name}):AFTER\\n${c_green}GIT_DIR!${c_clear}" >expected &&
 	echo "dirty" >file &&
 	test_when_finished "git reset --hard" &&
 	(
@@ -631,7 +631,7 @@ test_expect_success 'prompt - bash color pc mode - inside .git directory' '
 '
 
 test_expect_success 'prompt - bash color pc mode - stash status indicator' '
-	printf "BEFORE: (${c_green}\${__git_ps1_branch_name}${c_clear} ${c_lblue}\$${c_clear}):AFTER\\nmain" >expected &&
+	printf "BEFORE: (\${__git_ps1_branch_name} ${c_lblue}\$${c_clear}):AFTER\\n${c_green}main${c_clear}" >expected &&
 	echo 2 >file &&
 	git stash &&
 	test_when_finished "git stash drop" &&
@@ -645,7 +645,7 @@ test_expect_success 'prompt - bash color pc mode - stash status indicator' '
 '
 
 test_expect_success 'prompt - bash color pc mode - untracked files status indicator' '
-	printf "BEFORE: (${c_green}\${__git_ps1_branch_name}${c_clear} ${c_red}%%${c_clear}):AFTER\\nmain" >expected &&
+	printf "BEFORE: (\${__git_ps1_branch_name} ${c_red}%%${c_clear}):AFTER\\n${c_green}main${c_clear}" >expected &&
 	(
 		GIT_PS1_SHOWUNTRACKEDFILES=y &&
 		GIT_PS1_SHOWCOLORHINTS=y &&
-- 
2.36.1