Support ! negation in .kickflipignore

README.md

@@ -56,6 +56,15 @@ You may want to statically upload the contents of a folder. For example maybe th
 
 **Caveat**: To ignore files the `.kickflipignore` file must be present IN the folder.
 
+### .kickflipignore
+
+One glob per line. A line starting with `!` re-includes files another pattern ignored, e.g. ignore all dotfiles but still deploy `.htaccess`:
+
+    .*
+    !.htaccess
+
+Unlike `.gitignore`, order doesn't matter: a `!` pattern always wins.
+
 ### Pull request comments
 
 Kickflip can post a summary of the changes that will be deployed as a comment on a pull request:

src/kickflip.Tests/IgnoreServiceTests.cs

@@ -27,6 +27,20 @@ public void IsIgnored_HonoursPatternsInIgnoreFile()
         Assert.False(service.IsIgnored("index.html"));
     }
 
+    [Fact]
+    public void IsIgnored_NegatedPatternReincludesFile()
+    {
+        using var directory = new TempDirectory();
+        directory.WriteFile(".kickflipignore", ".*\n!.htaccess\n!.user.ini");
+        var service = new IgnoreService(directory.Path);
+
+        Assert.True(service.IsIgnored(".env"));
+        Assert.False(service.IsIgnored(".htaccess"));
+        Assert.False(service.IsIgnored(".user.ini"));
+        Assert.False(service.IsIgnored("index.php"));
+        Assert.True(service.IsIgnored(".kickflipignore"));
+    }
+
     [Fact]
     public void IsIgnored_AlwaysIgnoresTheIgnoreFileItself()
     {

src/kickflip/Services/IgnoreService.cs

@@ -17,8 +17,18 @@ public IgnoreService(string localPath)
             return;
         }
 
-        var ignorePatterns = File.ReadAllLines(ignoreFile);
-        _matcher.AddIncludePatterns(ignorePatterns);
+        foreach (var pattern in File.ReadAllLines(ignoreFile))
+        {
+            // "!pattern" re-includes files an earlier pattern ignored; unlike .gitignore, order doesn't matter
+            if (pattern.StartsWith('!'))
+            {
+                _matcher.AddExclude(pattern[1..]);
+            }
+            else
+            {
+                _matcher.AddInclude(pattern);
+            }
+        }
     }
 
     public bool IsIgnored(string path)