fix: do not error when no steps in a rebase

integration/git_prompt_string_test.go

@@ -37,10 +37,12 @@ func TestGitPromptString(t *testing.T) {
 		// rebase merge
 		{"rebase_i", []string{"--config=NONE"}, "\x1b[34m \ue0a0 main|REBASE-i 1/1\x1b[0m", nil, nil},
 		{"rebase_m", []string{"--config=NONE"}, "\x1b[34m \ue0a0 main|REBASE-m 1/1\x1b[0m", nil, nil},
+		{"rebase_i_no_steps", []string{"--config=NONE"}, "\x1b[34m \ue0a0 main|REBASE-i\x1b[0m", nil, nil},
 		// rebase apply
 		{"am_rebase", []string{"--config=NONE"}, "\x1b[34m \ue0a0 (b69e688)|AM/REBASE 1/1\x1b[0m", nil, nil},
 		{"am", []string{"--config=NONE"}, "\x1b[34m \ue0a0 (b69e688)|AM 1/1\x1b[0m", nil, nil},
 		{"rebase", []string{"--config=NONE"}, "\x1b[34m \ue0a0 main|REBASE 1/1\x1b[0m", nil, nil},
+		{"rebase_no_steps", []string{"--config=NONE"}, "\x1b[34m \ue0a0 main|REBASE\x1b[0m", nil, nil},
 		// merge
 		{"merge_conflict", []string{"--config=NONE"}, "\x1b[31m \ue0a0 main|MERGING|CONFLICT *↕ ↑[1] ↓[1]\x1b[0m", nil, nil},
 		{"merge", []string{"--config=NONE"}, "\x1b[35m \ue0a0 main|MERGING *↕ ↑[1] ↓[1]\x1b[0m", nil, nil},

pkg/git/repo.go

@@ -70,6 +70,14 @@ func (g *GitRepo) ReadGitDirFileExitOnError(name string) string {
 	return content
 }
 
+func (g *GitRepo) ReadGitDirFileEmptyOnError(name string) string {
+	content, err := g.ReadGitDirFile(name)
+	if err != nil {
+		return ""
+	}
+	return content
+}
+
 func (g *GitRepo) BranchInfo(cfg config.GitPromptStringConfig) (string, error) {
 	var err error
 	ref := ""
@@ -78,17 +86,17 @@ func (g *GitRepo) BranchInfo(cfg config.GitPromptStringConfig) (string, error) {
 
 	if g.IsGitDir("rebase-merge") {
 		ref = g.ReadGitDirFileExitOnError("rebase-merge/head-name")
-		step = g.ReadGitDirFileExitOnError("rebase-merge/msgnum")
-		total = g.ReadGitDirFileExitOnError("rebase-merge/end")
+		step = g.ReadGitDirFileEmptyOnError("rebase-merge/msgnum")
+		total = g.ReadGitDirFileEmptyOnError("rebase-merge/end")
 		g.PromptMergeStatus = "|REBASE-m"
 		if g.GitDirFileExistsExitOnError("rebase-merge/interactive") {
 			g.PromptMergeStatus = "|REBASE-i"
 		}
 	} else {
 		switch {
 		case g.IsGitDir("rebase-apply"):
-			step = g.ReadGitDirFileExitOnError("rebase-apply/next")
-			total = g.ReadGitDirFileExitOnError("rebase-apply/last")
+			step = g.ReadGitDirFileEmptyOnError("rebase-apply/next")
+			total = g.ReadGitDirFileEmptyOnError("rebase-apply/last")
 			switch {
 			case g.GitDirFileExistsExitOnError("rebase-apply/rebasing"):
 				ref = g.ReadGitDirFileExitOnError("rebase-apply/head-name")

testdata/rebase_i_no_steps/README.md

@@ -0,0 +1,3 @@
+# Test Repo
+
+Modified line

testdata/rebase_i_no_steps/dot_git/COMMIT_EDITMSG

@@ -0,0 +1,21 @@
+chore: ahead
+# Please enter the commit message for your changes. Lines starting
+# with '#' will be ignored, and an empty message aborts the commit.
+#
+# On branch main
+# Your branch is up to date with 'origin/main'.
+#
+# Changes to be committed:
+#	modified:   README.md
+#
+# ------------------------ >8 ------------------------
+# Do not modify or remove the line above.
+# Everything below it will be ignored.
+diff --git a/README.md b/README.md
+index a8cdb91..a60a2fa 100644
+--- a/README.md
++++ b/README.md
+@@ -1 +1,3 @@
+ # Test Repo
++
++Modified line

testdata/rebase_i_no_steps/dot_git/HEAD

@@ -0,0 +1 @@
+b69e688b26a7ca0498b0cbd8b3e6e189d987b661

testdata/rebase_i_no_steps/dot_git/ORIG_HEAD

@@ -0,0 +1 @@
+b69e688b26a7ca0498b0cbd8b3e6e189d987b661

testdata/rebase_i_no_steps/dot_git/REBASE_HEAD

@@ -0,0 +1 @@
+b69e688b26a7ca0498b0cbd8b3e6e189d987b661

testdata/rebase_i_no_steps/dot_git/config

@@ -0,0 +1,13 @@
+[core]
+	repositoryformatversion = 0
+	filemode = true
+	bare = false
+	logallrefupdates = true
+	ignorecase = true
+	precomposeunicode = true
+[remote "origin"]
+	url = [email protected]:mikesmithgh/test.git
+	fetch = +refs/heads/*:refs/remotes/origin/*
+[branch "main"]
+	remote = origin
+	merge = refs/heads/main

testdata/rebase_i_no_steps/dot_git/description

@@ -0,0 +1 @@
+Unnamed repository; edit this file 'description' to name the repository.

testdata/rebase_i_no_steps/dot_git/hooks/applypatch-msg.sample

@@ -0,0 +1,15 @@
+#!/bin/sh
+#
+# An example hook script to check the commit log message taken by
+# applypatch from an e-mail message.
+#
+# The hook should exit with non-zero status after issuing an
+# appropriate message if it wants to stop the commit.  The hook is
+# allowed to edit the commit message file.
+#
+# To enable this hook, rename this file to "applypatch-msg".
+
+. git-sh-setup
+commitmsg="$(git rev-parse --git-path hooks/commit-msg)"
+test -x "$commitmsg" && exec "$commitmsg" ${1+"$@"}
+:

testdata/rebase_i_no_steps/dot_git/hooks/commit-msg.sample

@@ -0,0 +1,24 @@
+#!/bin/sh
+#
+# An example hook script to check the commit log message.
+# Called by "git commit" with one argument, the name of the file
+# that has the commit message.  The hook should exit with non-zero
+# status after issuing an appropriate message if it wants to stop the
+# commit.  The hook is allowed to edit the commit message file.
+#
+# To enable this hook, rename this file to "commit-msg".
+
+# Uncomment the below to add a Signed-off-by line to the message.
+# Doing this in a hook is a bad idea in general, but the prepare-commit-msg
+# hook is more suited to it.
+#
+# SOB=$(git var GIT_AUTHOR_IDENT | sed -n 's/^\(.*>\).*$/Signed-off-by: \1/p')
+# grep -qs "^$SOB" "$1" || echo "$SOB" >> "$1"
+
+# This example catches duplicate Signed-off-by lines.
+
+test "" = "$(grep '^Signed-off-by: ' "$1" |
+	 sort | uniq -c | sed -e '/^[ 	]*1[ 	]/d')" || {
+	echo >&2 Duplicate Signed-off-by lines.
+	exit 1
+}

testdata/rebase_i_no_steps/dot_git/hooks/fsmonitor-watchman.sample

@@ -0,0 +1,174 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use IPC::Open2;
+
+# An example hook script to integrate Watchman
+# (https://facebook.github.io/watchman/) with git to speed up detecting
+# new and modified files.
+#
+# The hook is passed a version (currently 2) and last update token
+# formatted as a string and outputs to stdout a new update token and
+# all files that have been modified since the update token. Paths must
+# be relative to the root of the working tree and separated by a single NUL.
+#
+# To enable this hook, rename this file to "query-watchman" and set
+# 'git config core.fsmonitor .git/hooks/query-watchman'
+#
+my ($version, $last_update_token) = @ARGV;
+
+# Uncomment for debugging
+# print STDERR "$0 $version $last_update_token\n";
+
+# Check the hook interface version
+if ($version ne 2) {
+	die "Unsupported query-fsmonitor hook version '$version'.\n" .
+	    "Falling back to scanning...\n";
+}
+
+my $git_work_tree = get_working_dir();
+
+my $retry = 1;
+
+my $json_pkg;
+eval {
+	require JSON::XS;
+	$json_pkg = "JSON::XS";
+	1;
+} or do {
+	require JSON::PP;
+	$json_pkg = "JSON::PP";
+};
+
+launch_watchman();
+
+sub launch_watchman {
+	my $o = watchman_query();
+	if (is_work_tree_watched($o)) {
+		output_result($o->{clock}, @{$o->{files}});
+	}
+}
+
+sub output_result {
+	my ($clockid, @files) = @_;
+
+	# Uncomment for debugging watchman output
+	# open (my $fh, ">", ".git/watchman-output.out");
+	# binmode $fh, ":utf8";
+	# print $fh "$clockid\n@files\n";
+	# close $fh;
+
+	binmode STDOUT, ":utf8";
+	print $clockid;
+	print "\0";
+	local $, = "\0";
+	print @files;
+}
+
+sub watchman_clock {
+	my $response = qx/watchman clock "$git_work_tree"/;
+	die "Failed to get clock id on '$git_work_tree'.\n" .
+		"Falling back to scanning...\n" if $? != 0;
+
+	return $json_pkg->new->utf8->decode($response);
+}
+
+sub watchman_query {
+	my $pid = open2(\*CHLD_OUT, \*CHLD_IN, 'watchman -j --no-pretty')
+	or die "open2() failed: $!\n" .
+	"Falling back to scanning...\n";
+
+	# In the query expression below we're asking for names of files that
+	# changed since $last_update_token but not from the .git folder.
+	#
+	# To accomplish this, we're using the "since" generator to use the
+	# recency index to select candidate nodes and "fields" to limit the
+	# output to file names only. Then we're using the "expression" term to
+	# further constrain the results.
+	my $last_update_line = "";
+	if (substr($last_update_token, 0, 1) eq "c") {
+		$last_update_token = "\"$last_update_token\"";
+		$last_update_line = qq[\n"since": $last_update_token,];
+	}
+	my $query = <<"	END";
+		["query", "$git_work_tree", {$last_update_line
+			"fields": ["name"],
+			"expression": ["not", ["dirname", ".git"]]
+		}]
+	END
+
+	# Uncomment for debugging the watchman query
+	# open (my $fh, ">", ".git/watchman-query.json");
+	# print $fh $query;
+	# close $fh;
+
+	print CHLD_IN $query;
+	close CHLD_IN;
+	my $response = do {local $/; <CHLD_OUT>};
+
+	# Uncomment for debugging the watch response
+	# open ($fh, ">", ".git/watchman-response.json");
+	# print $fh $response;
+	# close $fh;
+
+	die "Watchman: command returned no output.\n" .
+	"Falling back to scanning...\n" if $response eq "";
+	die "Watchman: command returned invalid output: $response\n" .
+	"Falling back to scanning...\n" unless $response =~ /^\{/;
+
+	return $json_pkg->new->utf8->decode($response);
+}
+
+sub is_work_tree_watched {
+	my ($output) = @_;
+	my $error = $output->{error};
+	if ($retry > 0 and $error and $error =~ m/unable to resolve root .* directory (.*) is not watched/) {
+		$retry--;
+		my $response = qx/watchman watch "$git_work_tree"/;
+		die "Failed to make watchman watch '$git_work_tree'.\n" .
+		    "Falling back to scanning...\n" if $? != 0;
+		$output = $json_pkg->new->utf8->decode($response);
+		$error = $output->{error};
+		die "Watchman: $error.\n" .
+		"Falling back to scanning...\n" if $error;
+
+		# Uncomment for debugging watchman output
+		# open (my $fh, ">", ".git/watchman-output.out");
+		# close $fh;
+
+		# Watchman will always return all files on the first query so
+		# return the fast "everything is dirty" flag to git and do the
+		# Watchman query just to get it over with now so we won't pay
+		# the cost in git to look up each individual file.
+		my $o = watchman_clock();
+		$error = $output->{error};
+
+		die "Watchman: $error.\n" .
+		"Falling back to scanning...\n" if $error;
+
+		output_result($o->{clock}, ("/"));
+		$last_update_token = $o->{clock};
+
+		eval { launch_watchman() };
+		return 0;
+	}
+
+	die "Watchman: $error.\n" .
+	"Falling back to scanning...\n" if $error;
+
+	return 1;
+}
+
+sub get_working_dir {
+	my $working_dir;
+	if ($^O =~ 'msys' || $^O =~ 'cygwin') {
+		$working_dir = Win32::GetCwd();
+		$working_dir =~ tr/\\/\//;
+	} else {
+		require Cwd;
+		$working_dir = Cwd::cwd();
+	}
+
+	return $working_dir;
+}

testdata/rebase_i_no_steps/dot_git/hooks/post-update.sample

@@ -0,0 +1,8 @@
+#!/bin/sh
+#
+# An example hook script to prepare a packed repository for use over
+# dumb transports.
+#
+# To enable this hook, rename this file to "post-update".
+
+exec git update-server-info

testdata/rebase_i_no_steps/dot_git/hooks/pre-applypatch.sample

@@ -0,0 +1,14 @@
+#!/bin/sh
+#
+# An example hook script to verify what is about to be committed
+# by applypatch from an e-mail message.
+#
+# The hook should exit with non-zero status after issuing an
+# appropriate message if it wants to stop the commit.
+#
+# To enable this hook, rename this file to "pre-applypatch".
+
+. git-sh-setup
+precommit="$(git rev-parse --git-path hooks/pre-commit)"
+test -x "$precommit" && exec "$precommit" ${1+"$@"}
+:

testdata/rebase_i_no_steps/dot_git/hooks/pre-commit.sample

@@ -0,0 +1,49 @@
+#!/bin/sh
+#
+# An example hook script to verify what is about to be committed.
+# Called by "git commit" with no arguments.  The hook should
+# exit with non-zero status after issuing an appropriate message if
+# it wants to stop the commit.
+#
+# To enable this hook, rename this file to "pre-commit".
+
+if git rev-parse --verify HEAD >/dev/null 2>&1
+then
+	against=HEAD
+else
+	# Initial commit: diff against an empty tree object
+	against=$(git hash-object -t tree /dev/null)
+fi
+
+# If you want to allow non-ASCII filenames set this variable to true.
+allownonascii=$(git config --type=bool hooks.allownonascii)
+
+# Redirect output to stderr.
+exec 1>&2
+
+# Cross platform projects tend to avoid non-ASCII filenames; prevent
+# them from being added to the repository. We exploit the fact that the
+# printable range starts at the space character and ends with tilde.
+if [ "$allownonascii" != "true" ] &&
+	# Note that the use of brackets around a tr range is ok here, (it's
+	# even required, for portability to Solaris 10's /usr/bin/tr), since
+	# the square bracket bytes happen to fall in the designated range.
+	test $(git diff-index --cached --name-only --diff-filter=A -z $against |
+	  LC_ALL=C tr -d '[ -~]\0' | wc -c) != 0
+then
+	cat <<\EOF
+Error: Attempt to add a non-ASCII file name.
+
+This can cause problems if you want to work with people on other platforms.
+
+To be portable it is advisable to rename the file.
+
+If you know what you are doing you can disable this check using:
+
+  git config hooks.allownonascii true
+EOF
+	exit 1
+fi
+
+# If there are whitespace errors, print the offending file names and fail.
+exec git diff-index --check --cached $against --