From 32ffdfe85530d9569efb58983e5b630bda414d53 Mon Sep 17 00:00:00 2001
From: CreepySkeleton <creepy-skeleton@yandex.ru>
Date: Mon, 20 Apr 2020 13:28:50 +0300
Subject: [PATCH] Correctly handle `-f==a` (value is `=a`)

---
 src/parse/parser.rs     |  9 ++++-----
 src/util/osstringext.rs | 17 +++++++++++++++++
 2 files changed, 21 insertions(+), 5 deletions(-)

diff --git a/src/parse/parser.rs b/src/parse/parser.rs
index 0d1d1e52..1046bdf3 100644
--- a/src/parse/parser.rs
+++ b/src/parse/parser.rs
@@ -1215,7 +1215,7 @@ where
                     p[1].as_bytes()
                 );
                 let i = p[0].as_bytes().len() + 1;
-                let val = if !p[1].as_bytes().is_empty() {
+                let val = if !p[1].is_empty() {
                     debugln!(
                         "Parser::parse_short_arg:iter:{}: val={:?} (bytes), val={:?} (ascii)",
                         c,
@@ -1228,11 +1228,10 @@ where
                 };
 
                 // Default to "we're expecting a value later"
-                let ret = self.parse_opt(val, opt, false, matcher)?;
-
-                return Ok(ret);
+                return self.parse_opt(val, opt, false, matcher);
             } else {
                 let arg = format!("-{}", c);
+
                 return Err(ClapError::unknown_argument(
                     &*arg,
                     None,
@@ -1262,7 +1261,7 @@ where
         debug!("Parser::parse_opt; Checking for val...");
         if let Some(fv) = val {
             has_eq = fv.starts_with(&[b'=']) || had_eq;
-            let v = fv.trim_start_matches(b'=');
+            let v = fv.trim_start_n_matches(1, b'=');
             if !empty_vals && (v.is_empty() || (needs_eq && !has_eq)) {
                 sdebugln!("Found Empty - Error");
                 return Err(ClapError::empty_value(
diff --git a/src/util/osstringext.rs b/src/util/osstringext.rs
index 22d4ee62..f41b7d9b 100644
--- a/src/util/osstringext.rs
+++ b/src/util/osstringext.rs
@@ -15,6 +15,7 @@ pub(crate) trait OsStrExt2 {
     fn split_at_byte(&self, b: u8) -> (&OsStr, &OsStr);
     fn split_at(&self, i: usize) -> (&OsStr, &OsStr);
     fn trim_start_matches(&self, b: u8) -> &OsStr;
+    fn trim_start_n_matches(&self, n: usize, ch: u8) -> &OsStr;
     fn contains_byte(&self, b: u8) -> bool;
     fn split(&self, b: u8) -> OsSplit;
 }
@@ -75,6 +76,22 @@ impl OsStrExt2 for OsStr {
         &*self
     }
 
+    // Like `trim_start_matches`, but trims no more than `n` matches
+    #[inline]
+    fn trim_start_n_matches(&self, n: usize, ch: u8) -> &OsStr {
+        let i = self
+            .as_bytes()
+            .into_iter()
+            .take(n)
+            .take_while(|c| **c == ch)
+            .enumerate()
+            .last()
+            .map(|(i, _)| i + 1)
+            .unwrap_or(0);
+
+        self.split_at(i).1
+    }
+
     fn split_at(&self, i: usize) -> (&OsStr, &OsStr) {
         (
             OsStr::from_bytes(&self.as_bytes()[..i]),