From 069003fc7db3660f14ff90ddbf045ceb7bdec5fd Mon Sep 17 00:00:00 2001
From: Dmitry Afanasiev <afanasiev.dmitry@gmail.com>
Date: Wed, 3 Dec 2025 14:57:48 +0300
Subject: [PATCH] feat: allow skip inline comment strip logic

---
 dotconfig.go      | 13 ++++++++++---
 dotconfig_test.go | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/dotconfig.go b/dotconfig.go
index dcd47a2..c4f9afd 100644
--- a/dotconfig.go
+++ b/dotconfig.go
@@ -20,6 +20,7 @@ const (
 	EnforceStructTags                       // Make sure all fields in config struct have `env` struct tags
 	AllowWhitespace                         // Allow leading/trailing whitespace in string values
 	SkipNewlineDecoding                     // Don't turn "\n" into newlines
+	SkipCommentStrip                        // Don't exclude the comment from value that ends with #some_inline_comment
 )
 
 type options struct {
@@ -27,6 +28,7 @@ type options struct {
 	EnforceStructTags   bool
 	AllowWhitespace     bool
 	SkipNewlineDecoding bool
+	SkipCommentStrip    bool
 }
 
 func optsFromVariadic(opts []DecodeOption) options {
@@ -41,6 +43,8 @@ func optsFromVariadic(opts []DecodeOption) options {
 			v.AllowWhitespace = true
 		case SkipNewlineDecoding:
 			v.SkipNewlineDecoding = true
+		case SkipCommentStrip:
+			v.SkipCommentStrip = true
 		}
 	}
 	return v
@@ -113,9 +117,12 @@ func FromReader[T any](r io.Reader, opts ...DecodeOption) (T, error) {
 		key := line[0:strings.Index(line, "=")]
 		value := line[len(key)+1:]
 
-		// If there is a inline comment, so a space and then a #, exclude the comment.
-		if strings.Contains(value, " #") {
-			value = value[0:strings.Index(value, " #")]
+		if !decodedOpts.SkipCommentStrip {
+			// If there is a inline comment, so a space and then a #, exclude the comment.
+			ci := strings.Index(value, " #")
+			if ci >= 0 {
+				value = value[0:ci]
+			}
 		}
 
 		// Determine if our string is single quoted, double quoted, or just raw value.
diff --git a/dotconfig_test.go b/dotconfig_test.go
index eeab10c..a1206c4 100644
--- a/dotconfig_test.go
+++ b/dotconfig_test.go
@@ -251,3 +251,41 @@ func TestAllowWhitespace(t *testing.T) {
 		t.Error("Expected to allow whitespace.")
 	}
 }
+
+func TestInlineComments(t *testing.T) {
+	const dotenv = `
+# this is line comment
+            # and this also line comment
+FOO=bar     # this maybe part of FOO value (see SkipCommentStrip option)
+`
+
+	type configT struct {
+		Foo string `env:"FOO"`
+	}
+
+	{
+		const expected = "bar"
+		r := strings.NewReader(dotenv)
+		config, err := dotconfig.FromReader[configT](r, dotconfig.EnforceStructTags)
+		if err != nil {
+			t.Fatalf("unexpected error (SkipCommentStrip disabled):%v", err)
+		}
+
+		if config.Foo != expected {
+			t.Errorf("incorrect parsed value (SkipCommentStrip disabled), expected: %s, actual: %s", expected, config.Foo)
+		}
+	}
+
+	{
+		const expected = "bar     # this maybe part of FOO value (see SkipCommentStrip option)"
+		r := strings.NewReader(dotenv)
+		config, err := dotconfig.FromReader[configT](r, dotconfig.EnforceStructTags, dotconfig.SkipCommentStrip)
+		if err != nil {
+			t.Fatalf("unexpected error (SkipCommentStrip enabled) :%v", err)
+		}
+
+		if config.Foo != expected {
+			t.Errorf("incorrect parsed value (SkipCommentStrip enabled), expected: %s, actual: %s", expected, config.Foo)
+		}
+	}
+}