From cbab8677e672f562db1b990426d31dc853cb00f6 Mon Sep 17 00:00:00 2001
From: Sebastian Bentmar Holgersson <sbentmar@gmail.com>
Date: Tue, 3 Jan 2023 18:23:28 +0000
Subject: [PATCH] expand: improve handing of +

---
 src/uu/expand/src/expand.rs  | 18 +++++-----
 tests/by-util/test_expand.rs | 66 ++++++++++++++++++++++++++++++++++--
 2 files changed, 73 insertions(+), 11 deletions(-)

diff --git a/src/uu/expand/src/expand.rs b/src/uu/expand/src/expand.rs
index cbb5593f9..8ba9d74db 100644
--- a/src/uu/expand/src/expand.rs
+++ b/src/uu/expand/src/expand.rs
@@ -38,7 +38,7 @@ static DEFAULT_TABSTOP: usize = 8;
 
 /// The mode to use when replacing tabs beyond the last one specified in
 /// the `--tabs` argument.
-#[derive(PartialEq)]
+#[derive(PartialEq, Debug)]
 enum RemainingMode {
     None,
     Slash,
@@ -126,12 +126,8 @@ fn tabstops_parse(s: &str) -> Result<(RemainingMode, Vec<usize>), ParseError> {
         let bytes = word.as_bytes();
         for i in 0..bytes.len() {
             match bytes[i] {
-                b'+' => {
-                    remaining_mode = RemainingMode::Plus;
-                }
-                b'/' => {
-                    remaining_mode = RemainingMode::Slash;
-                }
+                b'+' => remaining_mode = RemainingMode::Plus,
+                b'/' => remaining_mode = RemainingMode::Slash,
                 _ => {
                     // Parse a number from the byte sequence.
                     let s = from_utf8(&bytes[i..]).unwrap();
@@ -190,10 +186,16 @@ fn tabstops_parse(s: &str) -> Result<(RemainingMode, Vec<usize>), ParseError> {
     // then just use the default tabstops.
     if nums.is_empty() {
         nums = vec![DEFAULT_TABSTOP];
+        remaining_mode = RemainingMode::None;
+    }
+
+    if nums.len() == 1 {
+        remaining_mode = RemainingMode::None;
     }
     Ok((remaining_mode, nums))
 }
 
+#[derive(Debug)]
 struct Options {
     files: Vec<String>,
     tabstops: Vec<usize>,
@@ -374,7 +376,7 @@ enum CharType {
 
 fn expand(options: &Options) -> std::io::Result<()> {
     use self::CharType::*;
-
+    println!("{:?}", options);
     let mut output = BufWriter::new(stdout());
     let ts = options.tabstops.as_ref();
     let mut buf = Vec::new();
diff --git a/tests/by-util/test_expand.rs b/tests/by-util/test_expand.rs
index ac9eb1fad..c4da7503f 100644
--- a/tests/by-util/test_expand.rs
+++ b/tests/by-util/test_expand.rs
@@ -275,7 +275,7 @@ fn test_tabs_shortcut() {
         .args(&["-2", "-5", "-7"])
         .pipe_in("\ta\tb\tc")
         .succeeds()
-        //          01234567890
+        //               01234567890
         .stdout_is("  a  b c");
 }
 
@@ -285,7 +285,7 @@ fn test_comma_separated_tabs_shortcut() {
         .args(&["-2,5", "-7"])
         .pipe_in("\ta\tb\tc")
         .succeeds()
-        //          01234567890
+        //               01234567890
         .stdout_is("  a  b c");
 }
 
@@ -295,6 +295,66 @@ fn test_tabs_and_tabs_shortcut_mixed() {
         .args(&["-2", "--tabs=5", "-7"])
         .pipe_in("\ta\tb\tc")
         .succeeds()
-        //          01234567890
+        //               01234567890
         .stdout_is("  a  b c");
 }
+
+#[test]
+fn test_ignore_initial_plus() {
+    new_ucmd!()
+        .args(&["--tabs=+3"])
+        .pipe_in("\ta\tb\tc")
+        .succeeds()
+        //               01234567890
+        .stdout_is("   a  b  c");
+}
+
+#[test]
+fn test_ignore_initial_pluses() {
+    new_ucmd!()
+        .args(&["--tabs=++3"])
+        .pipe_in("\ta\tb\tc")
+        .succeeds()
+        //               01234567890
+        .stdout_is("   a  b  c");
+}
+
+#[test]
+fn test_ignore_initial_slash() {
+    new_ucmd!()
+        .args(&["--tabs=/3"])
+        .pipe_in("\ta\tb\tc")
+        .succeeds()
+        //               01234567890
+        .stdout_is("   a  b  c");
+}
+
+#[test]
+fn test_ignore_initial_slashes() {
+    new_ucmd!()
+        .args(&["--tabs=//3"])
+        .pipe_in("\ta\tb\tc")
+        .succeeds()
+        //               01234567890
+        .stdout_is("   a  b  c");
+}
+
+#[test]
+fn test_ignore_initial_plus_slash_combination() {
+    new_ucmd!()
+        .args(&["--tabs=+/3"])
+        .pipe_in("\ta\tb\tc")
+        .succeeds()
+        //               01234567890
+        .stdout_is("   a  b  c");
+}
+
+#[test]
+fn test_comma_with_plus_and_multi_character_values() {
+    new_ucmd!()
+        .args(&["--tabs=3,+6"])
+        .pipe_in("\taaa\tbbbb\tcccc")
+        .succeeds()
+        //               01234567890
+        .stdout_is("   aaa   bbb   ccc");
+}