w3c · garretrieger · Mar 6, 2026 · Mar 5, 2026 · Mar 6, 2026 · Mar 6, 2026
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -22,6 +22,10 @@ jobs:
         run: |
           "${GITHUB_WORKSPACE}/bin/bazel" test -c opt ... --test_output=all
 
+      - name: Test (Default Build, No Dep Graph)
+        run: |
+          "${GITHUB_WORKSPACE}/bin/bazel" test --//:harfbuzz_dep_graph=False ... --test_output=all
+
   check_tests_osx:
     name: Check Tests (Mac OS)
     runs-on: macos-latest

diff --git a/BUILD b/BUILD
@@ -0,0 +1,15 @@
+load("@bazel_skylib//rules:common_settings.bzl", "bool_flag")
+
+bool_flag(
+    name = "harfbuzz_dep_graph",
+    build_setting_default = True,
+    visibility = ["//visibility:public"],
+)
+
+config_setting(
+    name = "use_harfbuzz_dep_graph",
+    flag_values = {
+        ":harfbuzz_dep_graph": "True",
+    },
+    visibility = ["//visibility:public"],
+)
diff --git a/MODULE.bazel b/MODULE.bazel
@@ -16,6 +16,7 @@ bazel_dep(name = "platforms", version = "1.0.0")
 bazel_dep(name = "rules_rust", version = "0.68.1")
 bazel_dep(name = "glib", version = "2.82.2.bcr.7")
 bazel_dep(name = "brotli", version = "1.2.0")
+bazel_dep(name = "bazel_skylib", version = "1.9.0")
 
 # Frequency Data
 bazel_dep(name = "ift_encoder_data", version = "git")

diff --git a/README.md b/README.md
@@ -5,11 +5,11 @@ This code repository contains an implementation of an
 
 ## Status
 
-This implementation is still in the early stages and as at the moment is work in progress. 
+This implementation is still in the early stages and as at the moment is work in progress.
 We aim to keep it updated and consistent with the current IFT specification working draft
 found [here](https://w3c.github.io/IFT/Overview.html).
 
-The current implementation is capable of producing a spec-compliant encoding, but does not 
+The current implementation is capable of producing a spec-compliant encoding, but does not
 yet fully support all aspects of the specification. Notably:
 
 *  Format 1 patch maps are not generated.
@@ -33,6 +33,19 @@ and run all of the tests:
 bazel test ...
 ```
 
+### Building without Dependency Graph Support
+
+By default this depends on the experimental harfbuzz dependency graph API which isn't yet in mainline harfbuzz.
+The dependency graph functionality can be disabled at compile time using the `harfbuzz_dep_graph` build flag.
+For example:
+
+```sh
+bazel build --//:harfbuzz_dep_graph=False ...
+bazel test --//:harfbuzz_dep_graph=False ...
+```
+
+Disabling the harfbuzz dependency graph api will cause segmenter runs using the `CLOSURE_AND_DEP_GRAPH` and `CLOSURE_AND_VALIDATE_DEP_GRAPH` condition analysis modes to fail.
+
 ## Code Style
 
 The code follows the [Google C++ Style Guide](https://google.github.io/styleguide/cppguide.html). Formatting is enforced by an automated check for new commits to this repo. You can auto-correct formatting for all files using the check-format.sh

diff --git a/common/BUILD b/common/BUILD
@@ -40,9 +40,6 @@ cc_library(
         "try.h",
         "woff2.h",
     ],
-    copts = [
-        "-DHB_EXPERIMENTAL_API",
-    ],
     visibility = [
         "//visibility:public",
     ],

diff --git a/ift/BUILD b/ift/BUILD
@@ -57,9 +57,6 @@ cc_test(
         "table_keyed_diff_test.cc",
         "url_template_test.cc",
     ],
-    copts = [
-        "-DHB_EXPERIMENTAL_API",
-    ],
     data = [
         "//common:testdata",
         "//ift:testdata",
@@ -80,9 +77,6 @@ cc_test(
     srcs = [
         "integration_test.cc",
     ],
-    copts = [
-        "-DHB_EXPERIMENTAL_API",
-    ],
     data = [
         "//common:testdata",
         "//ift:testdata",

diff --git a/ift/dep_graph/BUILD b/ift/dep_graph/BUILD
@@ -1,18 +1,18 @@
 load("@rules_cc//cc:cc_library.bzl", "cc_library")
 load("@rules_cc//cc:cc_test.bzl", "cc_test")
 
+
 cc_library(
     name = "dep_graph",
-    srcs = [
-        "dependency_graph.h",
-        "dependency_graph.cc",
-        "node.h",
-        "traversal.h",
-    ],
-    copts = [
-        "-DHB_EXPERIMENTAL_API",
-        "-DHB_DEPEND_API",
-    ],
+    srcs = select({
+        "//:use_harfbuzz_dep_graph": [
+            "dependency_graph.h",
+            "dependency_graph.cc",
+            "node.h",
+            "traversal.h",
+        ],
+        "//conditions:default": [],
+    }),
     visibility = [
         "//ift/encoder:__pkg__",
     ],
@@ -31,13 +31,12 @@ cc_library(
 cc_test(
     name = "dependency_graph_test",
     size = "small",
-    srcs = [
-        "dependency_graph_test.cc",
-    ],
-    copts = [
-        "-DHB_EXPERIMENTAL_API",
-        "-DHB_DEPEND_API",
-    ],
+    srcs = select({
+        "//:use_harfbuzz_dep_graph": [
+            "dependency_graph_test.cc",
+        ],
+        "//conditions:default": [],
+    }),
     data = [
         "//common:testdata",
     ],

diff --git a/ift/dep_graph/dependency_graph.h b/ift/dep_graph/dependency_graph.h
@@ -27,9 +27,9 @@ namespace ift::dep_graph {
 class TraversalContext;
 
 /*
- * Wrapper around harfbuzz's glyph depedency graph API.
+ * Wrapper around harfbuzz's glyph dependency graph API.
  *
- * Allows exploring glyph depedencies within a font.
+ * Allows exploring glyph dependencies within a font.
  */
 class DependencyGraph {
  public:

diff --git a/ift/dep_graph/dependency_graph_test.cc b/ift/dep_graph/dependency_graph_test.cc
@@ -318,8 +318,8 @@ TEST_F(DependencyGraphTest, ImpliedFeatureEdge_Liga) {
 // TODO(garretrieger):
 // - basic math, CFF, and COLR tests.
 
-// TODO(garretrieger) we currently only have a few specialized tests, relyng primarily on DepedencyClosureTest
-// for coverage of DepedencyGraph functionality. We should add some basic tests here that test DepedencyGraph
+// TODO(garretrieger) we currently only have a few specialized tests, relyng primarily on DependencyClosureTest
+// for coverage of DependencyGraph functionality. We should add some basic tests here that test DepedencyGraph
 // core features in isolation.
 
 }  // namespace ift::dep_graph
diff --git a/ift/dep_graph/node.h b/ift/dep_graph/node.h
@@ -10,7 +10,7 @@
 
 namespace ift::dep_graph {
 
-// A single node in a fonts glyph depedency graph.
+// A single node in a fonts glyph dependency graph.
 class Node {
  public:
   enum NodeType {

diff --git a/ift/dep_graph/traversal.h b/ift/dep_graph/traversal.h
@@ -9,7 +9,7 @@
 
 namespace ift::dep_graph {
 
-// A single node in a fonts glyph depedency graph.
+// A single node in a fonts glyph dependency graph.
 class Traversal {
  public:
   void SetPendingEdges() {

diff --git a/ift/encoder/BUILD b/ift/encoder/BUILD
@@ -9,10 +9,6 @@ cc_library(
         "compiler.cc",
         "compiler.h",
     ],
-    copts = [
-        "-DHB_EXPERIMENTAL_API",
-        "-DHB_DEPEND_API",
-    ],
     visibility = [
         "//ift:__subpackages__",
         "//ift/client:__pkg__",
@@ -60,7 +56,6 @@ cc_library(
         "candidate_merge.h",
         "complex_condition_finder.cc",
         "complex_condition_finder.h",
-        "dependency_closure.cc",
         "dependency_closure.h",
         "estimated_patch_size_cache.cc",
         "estimated_patch_size_cache.h",
@@ -78,11 +73,14 @@ cc_library(
         "requested_segmentation_information.h",
         "segmentation_context.cc",
         "segmentation_context.h",
-    ],
-    copts = [
-        "-DHB_EXPERIMENTAL_API",
-        "-DHB_DEPEND_API",
-    ],
+    ] + select({
+        "//:use_harfbuzz_dep_graph": [
+            "dependency_closure.cc",
+        ],
+        "//conditions:default": [
+            "dependency_closure_disabled.cc",
+        ],
+    }),
     visibility = [
     ],
     deps = [
@@ -145,9 +143,6 @@ cc_library(
         "subset_definition.h",
         "types.h",
     ],
-    copts = [
-        "-DHB_EXPERIMENTAL_API",
-    ],
     visibility = [
         "//visibility:public",
     ],
@@ -203,10 +198,6 @@ cc_test(
     srcs = [
         "glyph_segmentation_test.cc",
     ],
-    copts = [
-        "-DHB_EXPERIMENTAL_API",
-        "-DHB_DEPEND_API",
-    ],
     data = [
         "//common:testdata",
         "//ift:testdata",
@@ -225,10 +216,6 @@ cc_test(
     srcs = [
         "complex_condition_finder_test.cc",
     ],
-    copts = [
-        "-DHB_EXPERIMENTAL_API",
-        "-DHB_DEPEND_API",
-    ],
     data = [
         "//common:testdata",
         "//ift:testdata",
@@ -247,10 +234,6 @@ cc_test(
     srcs = [
         "closure_glyph_segmenter_test.cc",
     ],
-    copts = [
-        "-DHB_EXPERIMENTAL_API",
-        "-DHB_DEPEND_API",
-    ],
     data = [
         "//common:testdata",
         "//ift:testdata",
@@ -268,10 +251,6 @@ cc_test(
     srcs = [
         "glyph_closure_cache_test.cc",
     ],
-    copts = [
-        "-DHB_EXPERIMENTAL_API",
-        "-DHB_DEPEND_API",
-    ],
     data = [
         "//common:testdata",
     ],
@@ -289,10 +268,6 @@ cc_test(
     data = [
         "//common:testdata",
     ],
-    copts = [
-        "-DHB_EXPERIMENTAL_API",
-        "-DHB_DEPEND_API",
-    ],
     deps = [
         ":segmentation_context",
         "//common",
@@ -307,10 +282,6 @@ cc_test(
         "candidate_merge_test.cc",
         "mock_patch_size_cache.h",
     ],
-    copts = [
-        "-DHB_EXPERIMENTAL_API",
-        "-DHB_DEPEND_API",
-    ],
     data = [
         "//common:testdata",
     ],
@@ -339,13 +310,12 @@ cc_test(
 cc_test(
     name = "dependency_closure_test",
     size = "small",
-    srcs = [
-        "dependency_closure_test.cc",
-    ],
-    copts = [
-        "-DHB_EXPERIMENTAL_API",
-        "-DHB_DEPEND_API",
-    ],
+    srcs = select({
+        "//:use_harfbuzz_dep_graph": [
+            "dependency_closure_test.cc",
+        ],
+        "//conditions:default": [],
+    }),
     data = [
         "//common:testdata",
     ],

diff --git a/ift/encoder/closure_glyph_segmenter_test.cc b/ift/encoder/closure_glyph_segmenter_test.cc
@@ -36,9 +36,16 @@ class ClosureGlyphSegmenterTest : public ::testing::Test {
         segmenter_find_conditions(8, 8, FIND_CONDITIONS, CLOSURE_ONLY),
         segmenter_move_to_init_font(8, 8, MOVE_TO_INIT_FONT, CLOSURE_ONLY),
 
+#ifdef HB_DEPEND_API
         segmenter_dep_graph(8, 8, PATCH, CLOSURE_AND_VALIDATE_DEP_GRAPH),
         segmenter_find_conditions_dep_graph(8, 8, FIND_CONDITIONS, CLOSURE_AND_VALIDATE_DEP_GRAPH),
-        segmenter_move_to_init_font_dep_graph(8, 8, MOVE_TO_INIT_FONT, CLOSURE_AND_VALIDATE_DEP_GRAPH) {
+        segmenter_move_to_init_font_dep_graph(8, 8, MOVE_TO_INIT_FONT, CLOSURE_AND_VALIDATE_DEP_GRAPH)
+#else
+        segmenter_dep_graph(8, 8, PATCH, CLOSURE_ONLY),
+        segmenter_find_conditions_dep_graph(8, 8, FIND_CONDITIONS, CLOSURE_ONLY),
+        segmenter_move_to_init_font_dep_graph(8, 8, MOVE_TO_INIT_FONT, CLOSURE_ONLY)
+#endif
+         {
     roboto = from_file("common/testdata/Roboto-Regular.ttf");
     noto_nastaliq_urdu =
         from_file("common/testdata/NotoNastaliqUrdu.subset.ttf");

diff --git a/ift/encoder/dependency_closure.cc b/ift/encoder/dependency_closure.cc
@@ -28,7 +28,7 @@ using ift::dep_graph::Traversal;
 namespace ift::encoder {
 
 DependencyClosure::AnalysisAccuracy DependencyClosure::TraversalAccuracy(const Traversal& traversal) const {
-  // TODO(garretrieger): there's several types of depedencies that we do not handle yet and as a result
+  // TODO(garretrieger): there's several types of dependencies that we do not handle yet and as a result
   // consider inaccurate. Adding support for these will allow the dep graph to be used more widely:
   // - UVS edges: more complex case is generating conjunctive conditions from them.
   // - Ligatures: at least in simple non-nested cases we should be able to generate the corresponding conditions.