HarfBuzz text shaping engine
This report presents the forensic synthetic code analysis of harfbuzz/harfbuzz, a C++ project with 5,918 GitHub stars. SynthScan v2.0 examined 105,913 lines of code across 319 source files, recording 138 pattern matches distributed across 9 syntactic categories. The overall adjusted score of 3.0 places this repository in the Likely human-written band.
The scanner applied 160+ deterministic lexical heuristics, multi-line block detectors, abstract syntax tree depth profilers, and a cross-file Jaccard similarity matrix to construct a statistically normalised synthetic code estimate. All matches are individually weighted by severity coefficient and contextual multiplier before summation, and the resulting headline score is temporally discounted to account for the repository's development history relative to the commercial emergence of large language model coding tooling (November 2022 onward).
This chart maps the temporal evolution of the adjusted synthetic code score across successive scan runs. An upward trajectory indicates ongoing incorporation of AI-generated code or expanding LLM-assisted scaffolding; a stable or declining trajectory may reflect active human refactoring, code removal, or the adoption of stricter authorship policies. The dashed secondary line (right axis) independently tracks total raw pattern hit count, which can diverge from the normalised score when codebase size changes significantly between scans.
Classifies detected patterns by their diagnostic confidence and structural impact. CRITICAL patterns (coefficient 10) represent definitive synthetic signatures — hallucinated imports, explicit LLM attribution metadata — virtually never produced by human authors. HIGH (5) indicates strong structural tells such as cross-file repetition or cross-linguistic idioms. MEDIUM (2) covers recognisable conversational padding and AI-specific vocabulary. LOW (1) captures subtle indicators like tautological comments and generic boilerplate that require density to carry independent signal.
This horizontal bar chart decomposes the repository's raw synthetic code score by top-level directory, allowing you to pinpoint precisely which modules or components carry the highest AI authorship density. Directories with disproportionately high scores relative to their size warrant targeted manual review: concentrated AI signatures often trace back to mass-generated configuration layers, auto-ported test suites, LLM-scaffolded boilerplate classes, or entire subsystems authored under heavy copilot assistance. Use this view to prioritise your human code-review effort.
The scanner identified 138 distinct pattern matches across 9 syntactic categories. Each entry below represents a discrete location in the source code where the engine recorded a statistically significant AI authorship indicator. Expand any category row to inspect the individual file paths, line numbers, code snippets, and the lexical context (CODE, COMMENT, or STRING) in which each match was detected.
Reading the findings table: The Severity column indicates the diagnostic confidence level (CRITICAL / HIGH / MEDIUM / LOW). The Context column identifies whether the match occurred inside executable code, an inline comment, or a string literal — comment-context matches receive a ×1.5 weight because LLMs systematically over-annotate. The ⚡ bolt icon marks clustered matches: three or more patterns within a 10-line window, each receiving an additional ×1.5 density multiplier as dense clusters constitute far stronger evidence of synthetic authorship than isolated hits.
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 12 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 14 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 22 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 28 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 33 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 38 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 43 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 48 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 53 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 59 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 65 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 72 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 73 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 75 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 76 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 134 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 139 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 144 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 150 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 190 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 195 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 205 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 211 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 216 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 217 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 219 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 220 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 228 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 234 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 244 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 254 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 259 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 264 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 269 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicSyllabicCategory-Additional.txt | 274 | # ================================================ | COMMENT |
| MEDIUM | src/ms-use/IndicSyllabicCategory-Additional.txt | 163 | # ================================================ | COMMENT |
| MEDIUM | src/ms-use/IndicSyllabicCategory-Additional.txt | 175 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicPositionalCategory-Additional.txt | 14 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicPositionalCategory-Additional.txt | 15 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicPositionalCategory-Additional.txt | 17 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicPositionalCategory-Additional.txt | 18 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicPositionalCategory-Additional.txt | 35 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicPositionalCategory-Additional.txt | 40 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicPositionalCategory-Additional.txt | 48 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicPositionalCategory-Additional.txt | 59 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicPositionalCategory-Additional.txt | 65 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicPositionalCategory-Additional.txt | 66 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicPositionalCategory-Additional.txt | 68 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicPositionalCategory-Additional.txt | 69 | # ================================================ | COMMENT |
| MEDIUM | src/ms-use/IndicPositionalCategory-Additional.txt | 92 | # ================================================ | COMMENT |
| MEDIUM | src/ms-use/IndicPositionalCategory-Additional.txt | 97 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicPositionalCategory-Additional.txt | 114 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicPositionalCategory-Additional.txt | 119 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicPositionalCategory-Additional.txt | 120 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicPositionalCategory-Additional.txt | 122 | # ================================================ | COMMENT |
| MEDIUM⚡ | src/ms-use/IndicPositionalCategory-Additional.txt | 123 | # ================================================ | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| HIGH | src/gen-tag-table.py | 990 | print (' tags.push(%s); // %s' % (hb_tag_rust (tags[0]), ot.names[tags[0]])) | CODE |
| HIGH | src/gen-tag-table.py | 1031 | print (' tags.push(%s); // %s' % (hb_tag_rust (tags[0]), ot.names[tags[0]])) | CODE |
| HIGH | src/gen-tag-table.py | 1247 | print (" if (!p || p >= limit || limit - p < %i) goto out;" % min_subtag_len) | CODE |
| HIGH | src/gen-tag-table.py | 1275 | print (' for (i = 0; i < %s && i < *count; i++)' % len (tags)) | CODE |
| HIGH | src/gen-tag-table.py | 1327 | print (' for (i = 0; i < %s && i < *count; i++)' % len (tags)) | CODE |
| HIGH | src/gen-vowel-constraints.py | 308 | print (' for (buffer->idx = 0; buffer->idx + 1 < count && buffer->successful;)') | CODE |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | test/api/test-c.c | 41 | #include <hb-coretext.h> | COMMENT |
| LOW | test/api/test-c.c | 61 | #include <hb-graphite2.h> | COMMENT |
| LOW | util/hb-fc-list.c | 21 | * PERFORMANCE OF THIS SOFTWARE. | COMMENT |
| LOW | util/hb-fc-list.c | 41 | #define HAVE_GETOPT 1 | COMMENT |
| LOW | util/gpu/demo-common.h | 21 | #include <algorithm> | COMMENT |
| LOW | util/gpu/web/config-override.h | 1 | /* Re-enable features that HB_LEAN disables but the GPU demo needs. */ | COMMENT |
| LOW | util/gpu/web/gl-stub.h | 21 | /* Constants */ | COMMENT |
| LOW | util/gpu/web/gl-stub.h | 61 | #define GLFW_REPEAT 2 | COMMENT |
| LOW | util/gpu/web/gl-stub.h | 81 | #define GLFW_KEY_F 70 | COMMENT |
| LOW | src/hb-common.h | 41 | # ifdef __cplusplus | COMMENT |
| LOW | src/hb-common.h | 61 | typedef unsigned __int64 uint64_t; | COMMENT |
| LOW | src/hb-ot.h | 21 | * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO | COMMENT |
| LOW | src/hb-wasm-api.h | 41 | # define HB_WASM_END_DECLS } | COMMENT |
| LOW | src/hb-wasm-api.h | 61 | #define HB_WASM_EXEC_ENV | COMMENT |
| LOW | src/hb.h | 21 | * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO | COMMENT |
| LOW | src/hb.h | 41 | #include "hb-shape.h" | COMMENT |
| LOW | src/gen-ucd-table.py | 41 | # General_Category (gc), Canonical_Combining_Class (ccc), | COMMENT |
| LOW | src/ms-use/IndicSyllabicCategory-Additional.txt | 1 | # Override values For Indic_Syllabic_Category | COMMENT |
| LOW | src/ms-use/IndicPositionalCategory-Additional.txt | 1 | # Override values For Indic_Positional_Category | COMMENT |
| LOW | src/rust/hb.rs | 1 | #![allow(non_camel_case_types)] | COMMENT |
| LOW | src/wasm/rust/harfbuzz-wasm/src/lib.rs | 1 | #![warn(missing_docs)] | COMMENT |
| LOW | src/wasm/rust/harfbuzz-wasm/src/lib.rs | 241 | pub trait BufferItem { | COMMENT |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | test/subset/subset_test_suite.py | 123 | CODE | |
| LOW | test/shape/hb_test_tools.py | 79 | CODE | |
| LOW | test/shape/hb_test_tools.py | 135 | CODE | |
| LOW | test/shape/hb_test_tools.py | 225 | CODE | |
| LOW | test/shape/hb_test_tools.py | 347 | CODE | |
| LOW | test/shape/hb_test_tools.py | 444 | CODE | |
| LOW | test/fuzzing/decode-seed.py | 115 | CODE | |
| LOW | test/fuzzing/record-subset-test.py | 173 | CODE | |
| LOW | src/justify.py | 164 | CODE | |
| LOW | src/gen-arabic-table.py | 150 | CODE | |
| LOW | src/gen-tag-table.py | 1357 | CODE | |
| LOW | src/gen-tag-table.py | 360 | CODE | |
| LOW | src/gen-tag-table.py | 424 | CODE | |
| LOW | src/gen-tag-table.py | 473 | CODE | |
| LOW | src/gen-tag-table.py | 571 | CODE | |
| LOW | src/gen-vowel-constraints.py | 92 | CODE | |
| LOW | src/gen-vowel-constraints.py | 134 | CODE |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | test/subset/run-tests.py | 191 | def open_subset_batch_process(): | CODE |
| LOW | test/shape/hb_test_tools.py | 293 | def filter_printer_function_no_newline (filter_callback): | CODE |
| LOW | test/shape/hb_test_tools.py | 347 | def filter_multiple_strings_or_stdin (callback, mnemonic, \ | CODE |
| LOW | test/fuzzing/hb_fuzzing_tools.py | 102 | def emit_pin_all_axes_to_default(ops: bytearray) -> None: | CODE |
| LOW | test/fuzzing/record-subset-test.py | 163 | def handle_file_backed_set_option(ops: bytearray, name: str, path: str) -> None: | STRING |
| LOW | test/vector/run-tests.py | 36 | def open_vector_batch_process(): | CODE |
| LOW | test/vector/run-tests.py | 52 | def close_vector_batch_process(vector_process): | CODE |
| LOW | src/gen-tag-table.py | 473 | def inherit_from_macrolanguages (self): | CODE |
| LOW | src/gen-tag-table.py | 654 | def remove_extra_macrolanguages (self): | CODE |
| LOW | src/gen-tag-table.py | 900 | def language_name_intersection_rust (a, b): | CODE |
| LOW | src/gen-tag-table.py | 903 | def get_matching_language_name_rust (intersection, candidates): | CODE |
| LOW | src/gen-tag-table.py | 959 | def print_subtag_matches_rust (subtag, new_line): | CODE |
| LOW | src/gen-tag-table.py | 1094 | def language_name_intersection (a, b): | CODE |
| LOW | src/gen-tag-table.py | 1108 | def get_matching_language_name (intersection, candidates): | CODE |
| LOW | src/gen-tag-table.py | 1357 | def verify_disambiguation_dict (): | CODE |
| LOW | src/hb-unicode.h | 354 | typedef hb_unicode_combining_class_t (*hb_unicode_combining_class_func_t) (hb_unicode_funcs_t *ufuncs, | CODE |
| LOW | src/hb-unicode.h | 372 | typedef hb_unicode_general_category_t (*hb_unicode_general_category_func_t) (hb_unicode_funcs_t *ufuncs, | CODE |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | test/subset/run-repack-tests.py | 6 | CODE | |
| LOW | test/subset/run-repack-tests.py | 8 | CODE | |
| LOW | test/subset/run-repack-tests.py | 13 | CODE | |
| LOW | test/subset/run-tests.py | 8 | CODE | |
| LOW | test/shape/hb_test_tools.py | 4 | CODE | |
| LOW | test/shape/data/text-rendering-tests/update.py | 3 | CODE | |
| LOW | test/shape/data/text-rendering-tests/update.py | 3 | CODE | |
| LOW | test/fuzzing/decode-seed.py | 8 | CODE | |
| LOW | util/gpu/gen-default-texts.py | 5 | CODE | |
| LOW | src/gen-arabic-joining-list.py | 10 | CODE |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | util/gpu/default-text.txt | 1 | Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam tincidunt nibh quis semper malesuada. Mauris sit amet me | CODE |
| LOW | util/gpu/default-text.txt | 1 | Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam tincidunt nibh quis semper malesuada. Mauris sit amet me | CODE |
| LOW | util/gpu/web/dom.html | 26 | scene.textContent = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam tincidunt nibh quis semper malesuad | CODE |
| LOW | util/gpu/web/dom.html | 26 | scene.textContent = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam tincidunt nibh quis semper malesuad | CODE |
| LOW | perf/texts/en-paragraph.txt | 1 | Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam tincidunt nibh quis semper malesuada. Mauris sit amet me | CODE |
| LOW | perf/texts/en-paragraph.txt | 1 | Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam tincidunt nibh quis semper malesuada. Mauris sit amet me | CODE |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| LOW | test/subset/run-repack-tests.py | 80 | except Exception as e: | CODE |
| LOW | test/subset/run-tests.py | 130 | except Exception as e: | CODE |
| LOW | test/subset/run-tests.py | 139 | except Exception as e: | CODE |
| Severity | File | Line | Snippet | Context |
|---|---|---|---|---|
| MEDIUM | docs/usermanual-clusters.xml | 262 | As mentioned earlier, client programs using HarfBuzz often | CODE |