diff --git a/changelog.md b/changelog.md
index 9f42bd85f..f712d4813 100644
--- a/changelog.md
+++ b/changelog.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 <!-- Add all new changes here. They will be moved under a version at release -->
+* `FIX` A `.gitignore` line containing only whitespace no longer ignores the entire workspace [#3458](https://github.com/LuaLS/lua-language-server/issues/3458)
 * `FIX` `need-check-nil` diagnostic is no longer reported on safe navigation access (e.g. `x?.field`, `f?.()`, `t?.[key]`), since the optional access itself already handles the nil check. Note that a non-safe access chained after a safe one (e.g. `x.upper()?.field`) still reports, because the safe access only protects its own result.
 
 ## 3.19.1
diff --git a/script/glob/matcher.lua b/script/glob/matcher.lua
index af43e0879..5778d86f1 100644
--- a/script/glob/matcher.lua
+++ b/script/glob/matcher.lua
@@ -122,6 +122,9 @@ function mt:slash(_, state, index)
 end
 
 function mt:pattern(state)
+    if not state[1] then
+        return nil
+    end
     if state.root then
         local after = self:exp(state, 1)
         if after then
diff --git a/test/basic/gitignore.lua b/test/basic/gitignore.lua
new file mode 100644
index 000000000..ffa59633a
--- /dev/null
+++ b/test/basic/gitignore.lua
@@ -0,0 +1,30 @@
+local glob = require 'glob'
+
+local function ignored(patterns, path)
+    return glob.gitignore(patterns)(path)
+end
+
+-- #3458: a whitespace-only gitignore pattern must not match every path
+assert(ignored({ ' ' }, 'a.lua') == false)
+assert(ignored({ ' ' }, 'foo/bar.lua') == false)
+assert(ignored({ '\t' }, 'a.lua') == false)
+assert(ignored({ '' }, 'a.lua') == false)
+
+-- Real patterns in the same list still match; the blank line does not take over
+assert(ignored({ ' ', '*.log' }, 'a.lua') == false)
+assert(ignored({ ' ', '*.log' }, 'a.log') == true)
+
+-- Intentional match-all and ordinary names are unchanged
+assert(ignored({ '*' }, 'a.lua') == true)
+assert(ignored({ 'foo' }, 'foo') == true)
+assert(ignored({ 'foo' }, 'bar') == false)
+
+-- Quoted trailing space is a real pattern (gitignore spec), not a blank line
+assert(ignored({ '\\ ' }, 'a.lua') == false)
+assert(ignored({ '\\ ' }, ' ') == true)
+
+-- glob.glob shares the same matcher; empty patterns must not match everything
+assert(glob.glob({ ' ' })('a.lua') == false)
+assert(glob.glob({ ' ', 'foo' })('foo') == true)
+assert(glob.glob({ ' ', 'foo' })('bar') == false)
+assert(glob.glob({ '*' })('a.lua') == true)
diff --git a/test/basic/init.lua b/test/basic/init.lua
index 9030cf6dd..12ff244ee 100644
--- a/test/basic/init.lua
+++ b/test/basic/init.lua
@@ -1,2 +1,3 @@
 require 'basic.textmerger'
 require 'basic.filewatch'
+require 'basic.gitignore'