Fix 100035: Make UDIM detection less aggressive

There's been a handful of reports where "obviously" not a UDIM filenames
were detected as such during image open.[1]

This change makes the detection less aggressive by enforcing that the
4-digit sequence be delineated on both sides by one of the following 3
characters ., -, _

This fixes the problem for such filenames as:
"screenshot-1080p.png", "Image-1920x1080.png", "(1999) Photo.png", and
"antiguaChestnut_X_1240Wx814H.png"

[1] T97366 T98918 T99154 T100035

Differential Revision: https://developer.blender.org/D15573

2 files changed, 17 insertions, 7 deletions

diff --git a/source/blender/blenkernel/intern/image.cc b/source/blender/blenkernel/intern/image.cc
index c2b8ec95a46..ae5eead2547 100644
--- a/source/blender/blenkernel/intern/image.cc
+++ b/source/blender/blenkernel/intern/image.cc
@@ -3410,9 +3410,8 @@ void BKE_image_ensure_tile_token(char *filename)
 
   /* General 4-digit "udim" pattern. As this format is susceptible to ambiguity
    * with other digit sequences, we can leverage the supported range of roughly
-   * 1000 through 2000 to provide better detection.
-   */
-  std::regex pattern(R"((^|.*?\D)([12]\d{3})(\D.*))");
+   * 1000 through 2000 to provide better detection. */
+  std::regex pattern(R"((.*[._-])([12]\d{3})([._-].*))");
   if (std::regex_search(path, match, pattern)) {
     BLI_strncpy(filename, match.format("$1<UDIM>$3").c_str(), FILE_MAX);
     return;
diff --git a/source/blender/blenkernel/intern/image_test.cc b/source/blender/blenkernel/intern/image_test.cc
index 9c15fc62d21..7004d39c805 100644
--- a/source/blender/blenkernel/intern/image_test.cc
+++ b/source/blender/blenkernel/intern/image_test.cc
@@ -32,8 +32,12 @@ TEST(udim, image_ensure_tile_token)
   verify("test_1002_ao.png", "test_<UDIM>_ao.png");
   verify("test.1002.ver0023.png", "test.<UDIM>.ver0023.png");
   verify("test.ver0023.1002.png", "test.ver0023.<UDIM>.png");
-  verify("1002test.png", "<UDIM>test.png");
-  verify("test1002.png", "test<UDIM>.png");
+  verify("test.1002.1.png", "test.<UDIM>.1.png");
+  verify("test.1.1002.png", "test.1.<UDIM>.png");
+  verify("test-2022-01-01.1002.png", "test-2022-01-01.<UDIM>.png");
+  verify("1111_11.1002.png", "1111_11.<UDIM>.png");
+  verify("2111_01.1002.png", "2111_01.<UDIM>.png");
+  verify("2022_1002_100200.1002.png", "2022_1002_100200.<UDIM>.png");
 
   /* UVTILE pattern detection. */
   verify("uv-test.u2_v10.png", "uv-test.<UVTILE>.png");
@@ -44,8 +48,15 @@ TEST(udim, image_ensure_tile_token)
   verify("u2_v10uv-test.png", "<UVTILE>uv-test.png");
   verify("u2_v10u_v-test.png", "<UVTILE>u_v-test.png");
 
-  /* Incorrect patterns. */
-  for (const char *incorrect : {"test.123.png",
+  /* Patterns which should not be detected as UDIMs. */
+  for (const char *incorrect : {"1002.png",
+                                "1002test.png",
+                                "test1002.png",
+                                "test(1002).png",
+                                "(1002)test.png",
+                                "test-1080p.png",
+                                "test-1920x1080.png",
+                                "test.123.png",
                                 "test.12345.png",
                                 "test.uv.png",
                                 "test.u1v.png",