test(conformance): a digit-initial non-number is an error

README.md

@@ -48,7 +48,7 @@ The rest of this page reads these two files.
 
 ## Why zig-hocon
 
-- **Correct.** Passes 444 of the 445 tests in the [conformance suite](https://htmlpreview.github.io/?https://github.com/lejmr/zig-hocon/blob/main/conformance/report.html), one test for each sentence of the spec.\*
+- **Correct.** Passes 445 of the 446 tests in the [conformance suite](https://htmlpreview.github.io/?https://github.com/lejmr/zig-hocon/blob/main/conformance/report.html), one test for each sentence of the spec.\*
 - **Your schema is a Zig struct.** HOCON is only what sits on disk; the struct says what it holds, with defaults, optionals, enums, durations and sizes.
 - **Fast.** A 10 MB config in a quarter of a second.\*\*
 - **Clear errors.** File, line, column and a caret, also for a value of the wrong type.
@@ -211,13 +211,13 @@ b.step("check-config", "Check the config against Config").dependOn(&check.step);
 
 | implementation | against the spec | against typesafe/config 1.4.9 |
 |---|---|---|
-| Java <sub>typesafe/config 1.4.9</sub> | 90.1% (401/445) | 99.8% (444/445) |
-| hocon2 <sub>hocon2 0.6.3</sub> | 86.7% (386/445) | 80.7% (359/445) |
-| pulse-pyhocon <sub>pulse-pyhocon 0.2.1</sub> | 71.0% (316/445) | 68.5% (305/445) |
-| py.hocon <sub>hocon-parser 1.14.2 (Python)</sub> | 89.2% (397/445) | 88.5% (394/445) |
-| pyhocon <sub>pyhocon 0.3.63</sub> | 70.6% (314/445) | 66.7% (297/445) |
-| rs.hocon <sub>hocon-parser 1.14.2 (Rust)</sub> | 89.2% (397/445) | 86.5% (385/445) |
-| zig-hocon <sub>zig-hocon code@20663cc</sub> | 99.8% (444/445) | 90.1% (401/445) |
+| Java <sub>typesafe/config 1.4.9</sub> | 89.9% (401/446) | 99.8% (445/446) |
+| hocon2 <sub>hocon2 0.6.3</sub> | 86.5% (386/446) | 80.5% (359/446) |
+| pulse-pyhocon <sub>pulse-pyhocon 0.2.1</sub> | 70.9% (316/446) | 68.4% (305/446) |
+| py.hocon <sub>hocon-parser 1.14.2 (Python)</sub> | 89.0% (397/446) | 88.3% (394/446) |
+| pyhocon <sub>pyhocon 0.3.63</sub> | 70.4% (314/446) | 66.8% (298/446) |
+| rs.hocon <sub>hocon-parser 1.14.2 (Rust)</sub> | 89.0% (397/446) | 86.3% (385/446) |
+| zig-hocon <sub>zig-hocon code@031f68c</sub> | 99.8% (445/446) | 89.9% (401/446) |
 
 The table keeps the best parsers; the others measured, and why they are not in it: [conformance/README.md](conformance/README.md#not-in-the-table).
 

conformance/maintaining/COVERAGE.html

@@ -184,9 +184,9 @@ <h3>Unquoted strings</h3>
 forbidden character or the two-character string &quot;//&quot; is
 encountered.</mark> <mark class="ok" title="unquoted-strings.11 — unquoted-strings/010-embedded-null-not-recognized.conf">Embedded (non-initial) booleans, nulls, and numbers
 are not recognized as such, they are part of the string.</mark></p>
-<p data-line="270"><mark class="ok" title="unquoted-strings.12 — unquoted-strings/012-unquoted-cannot-start-with-hyphen.conf, unquoted-strings/018-leading-dot-is-not-a-number.conf">An unquoted string may not _begin_ with the digits 0-9 or with a
+<p data-line="270"><mark class="ok" title="unquoted-strings.12 — unquoted-strings/012-unquoted-cannot-start-with-hyphen.conf, unquoted-strings/018-leading-dot-is-not-a-number.conf, unquoted-strings/025-digit-initial-invalid-number.conf">An unquoted string may not _begin_ with the digits 0-9 or with a
 hyphen (`-`, 0x002D) because those are valid characters to begin a
-JSON number.</mark> <mark class="ok" title="unquoted-strings.13 — unquoted-strings/013-negative-number-then-string.conf, unquoted-strings/021-plus-inside-a-number-illegal.conf, unquoted-strings/022-digit-then-exponent-letter-illegal.conf">The initial number character, plus any valid-in-JSON
+JSON number.</mark> <mark class="ok" title="unquoted-strings.13 — unquoted-strings/013-negative-number-then-string.conf, unquoted-strings/021-plus-inside-a-number-illegal.conf, unquoted-strings/022-digit-then-exponent-letter-illegal.conf, unquoted-strings/025-digit-initial-invalid-number.conf">The initial number character, plus any valid-in-JSON
 number characters that follow it, must be parsed as a number
 value.</mark> Again, these characters are not special _inside_ an
 unquoted string; they only trigger number parsing if they appear

conformance/maintaining/FINDINGS.md

@@ -4,6 +4,10 @@
 
 What the validation pass turned up and did **not** fix. The divergences it was confident about are already in the sidecars; everything below is work, not record.
 
+**Since then:** proofreading the suite against `spec/HOCON.md` found a rule no case pinned, where zig-hocon and pyhocon part ways. It is covered now:
+
+- `unquoted-strings/025-digit-initial-invalid-number` — a value that begins with a digit but is not a valid number (`a = 1.2.3`, the shape of `127.0.0.1`) is an error: the initial number character and the number characters after it "must be parsed as a number value" (unquoted-strings.12, .13). pyhocon and typesafe/config read it as the string "1.2.3"; the row is `java: lenient`.
+
 This pass ran *before* the tie-break rule in `PROCESS.md` was settled, so where a divergence says `expect` was left at java's value, the row is still unresolved — `fill-expected.py` now flags those with `review`.
 
 ## syntax-basics
@@ -75,7 +79,7 @@ The section maps to the spec faithfully: all seventeen cases quote sentences tha
 
 **Uncovered normative sentences**
 
-- "An unquoted string may not _begin_ with the digits 0-9" -- no case covers a digit-initial sequence whose number parse fails (e.g. `a = 1.2.3` or `a = 1x2`). 008 (`10.0bar`) only covers the case where the leading run IS a valid number. This is the digit-side twin of the hyphen divergence in 012 and is where java's number-parse fallback to unquoted text shows again; it is the most valuable uncovered sentence in the range.
+- "An unquoted string may not _begin_ with the digits 0-9" -- no case covers a digit-initial sequence whose number parse fails (e.g. `a = 1.2.3` or `a = 1x2`). 008 (`10.0bar`) only covers the case where the leading run IS a valid number. This is the digit-side twin of the hyphen divergence in 012 and is where java's number-parse fallback to unquoted text shows again; it is the most valuable uncovered sentence in the range. _(covered since by 025-digit-initial-invalid-number)_
 - "forbidden characters: ... or whitespace" -- whitespace is listed as a forbidden character, but no case pins that whitespace ends an unquoted string (the covered forbidden chars are only '@', '\\', '!', '#'). Hard to isolate because `a = foo bar` becomes a value concatenation, but the list member is currently untested here.
 - "its initial characters do not parse as `true`, `false`, `null`, or a number" -- only the `true` arm is exercised (006). No case starts a token with `false` or `null` (e.g. `a = nullfoo`, `a = falsefoo`).
 

conformance/maintaining/SECTIONS.md

@@ -16,7 +16,7 @@ observable parse behaviour.
 | 149 | Commas | `commas` | ✅ 13 cases |
 | 165 | Whitespace | `whitespace` | ✅ 13 cases |
 | 186 | Duplicate keys and object merging | `duplicate-keys-and-object-merging` | ✅ 28 cases |
-| 240 | Unquoted strings | `unquoted-strings` | ✅ 24 cases |
+| 240 | Unquoted strings | `unquoted-strings` | ✅ 25 cases |
 | 288 | Multi-line strings | `multi-line-strings` | ✅ 9 cases |
 | 304 | Value concatenation | `value-concatenation` | ✅ 2 cases |
 | 321 | String value concatenation | `string-value-concatenation` | ✅ 18 cases |

conformance/reports/Java.java.json

@@ -5,10 +5,10 @@
   "mode": "java",
   "java_version": "1.4.9",
   "command": "conformance/adapters/oracle.sh hocon-java",
-  "ran_at": "2026-10-19T05:59:42Z",
-  "suite_digest": "cd4bdae3133b2042",
-  "total": 445,
-  "passed": 444,
+  "ran_at": "2026-10-22T19:43:12Z",
+  "suite_digest": "e05749cb283ceff4",
+  "total": 446,
+  "passed": 445,
   "percent": 99.8,
   "sections": {
     "array-and-object-concatenation": {
@@ -136,8 +136,8 @@
       "passed": 6
     },
     "unquoted-strings": {
-      "total": 24,
-      "passed": 24
+      "total": 25,
+      "passed": 25
     },
     "value-concatenation": {
       "total": 2,
@@ -579,6 +579,7 @@
     "unquoted-strings/022-digit-then-exponent-letter-illegal.conf": "pass",
     "unquoted-strings/023-unquoted-string-ends-at-end-of-file.conf": "pass",
     "unquoted-strings/024-escape-sequence-in-unquoted-string-illegal.conf": "pass",
+    "unquoted-strings/025-digit-initial-invalid-number.conf": "pass",
     "value-concatenation/001-simple-values-concatenate-to-string.conf": "pass",
     "value-concatenation/004-string-concatenation-allowed-in-field-keys.conf": "pass",
     "whitespace/001-nonbreaking-space-as-whitespace.conf": "pass",
@@ -639,7 +640,8 @@
     "unchanged-from-json/013-trailing-dot-before-exponent-illegal.conf": "{\"a\":-1000}",
     "unchanged-from-json/014-negative-leading-zeros-illegal.conf": "{\"a\":-33}",
     "unquoted-strings/012-unquoted-cannot-start-with-hyphen.conf": "{\"a\":\"-foo\"}",
-    "unquoted-strings/022-digit-then-exponent-letter-illegal.conf": "{\"a\":\"1e\"}"
+    "unquoted-strings/022-digit-then-exponent-letter-illegal.conf": "{\"a\":\"1e\"}",
+    "unquoted-strings/025-digit-initial-invalid-number.conf": "{\"a\":\"1.2.3\"}"
   },
   "failures": [
     {

conformance/reports/Java.spec.json

@@ -4,11 +4,11 @@
   "version": "typesafe/config 1.4.9",
   "mode": "spec",
   "command": "conformance/adapters/oracle.sh hocon-java",
-  "ran_at": "2026-10-19T05:59:42Z",
-  "suite_digest": "cd4bdae3133b2042",
-  "total": 445,
+  "ran_at": "2026-10-22T19:42:16Z",
+  "suite_digest": "e05749cb283ceff4",
+  "total": 446,
   "passed": 401,
-  "percent": 90.1,
+  "percent": 89.9,
   "sections": {
     "array-and-object-concatenation": {
       "total": 19,
@@ -135,7 +135,7 @@
       "passed": 6
     },
     "unquoted-strings": {
-      "total": 24,
+      "total": 25,
       "passed": 22
     },
     "value-concatenation": {
@@ -578,6 +578,7 @@
     "unquoted-strings/022-digit-then-exponent-letter-illegal.conf": "fail",
     "unquoted-strings/023-unquoted-string-ends-at-end-of-file.conf": "pass",
     "unquoted-strings/024-escape-sequence-in-unquoted-string-illegal.conf": "pass",
+    "unquoted-strings/025-digit-initial-invalid-number.conf": "fail",
     "value-concatenation/001-simple-values-concatenate-to-string.conf": "pass",
     "value-concatenation/004-string-concatenation-allowed-in-field-keys.conf": "pass",
     "whitespace/001-nonbreaking-space-as-whitespace.conf": "pass",
@@ -638,7 +639,8 @@
     "unchanged-from-json/013-trailing-dot-before-exponent-illegal.conf": "{\"a\":-1000}",
     "unchanged-from-json/014-negative-leading-zeros-illegal.conf": "{\"a\":-33}",
     "unquoted-strings/012-unquoted-cannot-start-with-hyphen.conf": "{\"a\":\"-foo\"}",
-    "unquoted-strings/022-digit-then-exponent-letter-illegal.conf": "{\"a\":\"1e\"}"
+    "unquoted-strings/022-digit-then-exponent-letter-illegal.conf": "{\"a\":\"1e\"}",
+    "unquoted-strings/025-digit-initial-invalid-number.conf": "{\"a\":\"1.2.3\"}"
   },
   "failures": [
     {
@@ -1278,6 +1280,14 @@
       "expected": "rejected",
       "got": "{\"a\":\"1e\"}",
       "java": "lenient"
+    },
+    {
+      "case": "unquoted-strings/025-digit-initial-invalid-number.conf",
+      "spec": "HOCON.md#unquoted-strings",
+      "rule": "an unquoted string may not begin with the digits 0-9, and the initial number character plus any valid-in-JSON number characters that follow it must be parsed as a number value -- 1.2.3 is that run, and it is not a number, so the input is rejected rather than read as a string (the everyday shape is an address like 127.0.0.1); typesafe/config and pyhocon both fall back to the unquoted string \"1.2.3\"",
+      "expected": "rejected",
+      "got": "{\"a\":\"1.2.3\"}",
+      "java": "lenient"
     }
   ]
 }

conformance/reports/pyhocon.java.json

@@ -5,11 +5,11 @@
   "mode": "java",
   "java_version": "1.4.9",
   "command": "conformance/adapters/oracle.sh hocon-py",
-  "ran_at": "2026-10-19T06:04:35Z",
-  "suite_digest": "cd4bdae3133b2042",
-  "total": 445,
-  "passed": 297,
-  "percent": 66.7,
+  "ran_at": "2026-10-22T19:40:53Z",
+  "suite_digest": "e05749cb283ceff4",
+  "total": 446,
+  "passed": 298,
+  "percent": 66.8,
   "sections": {
     "array-and-object-concatenation": {
       "total": 19,
@@ -136,8 +136,8 @@
       "passed": 5
     },
     "unquoted-strings": {
-      "total": 24,
-      "passed": 18
+      "total": 25,
+      "passed": 19
     },
     "value-concatenation": {
       "total": 2,
@@ -579,6 +579,7 @@
     "unquoted-strings/022-digit-then-exponent-letter-illegal.conf": "pass",
     "unquoted-strings/023-unquoted-string-ends-at-end-of-file.conf": "pass",
     "unquoted-strings/024-escape-sequence-in-unquoted-string-illegal.conf": "fail",
+    "unquoted-strings/025-digit-initial-invalid-number.conf": "pass",
     "value-concatenation/001-simple-values-concatenate-to-string.conf": "pass",
     "value-concatenation/004-string-concatenation-allowed-in-field-keys.conf": "pass",
     "whitespace/001-nonbreaking-space-as-whitespace.conf": "fail",
@@ -639,7 +640,8 @@
     "unchanged-from-json/013-trailing-dot-before-exponent-illegal.conf": "{\"a\":\"-1.e3\"}",
     "unchanged-from-json/014-negative-leading-zeros-illegal.conf": "{\"a\":-33}",
     "unquoted-strings/012-unquoted-cannot-start-with-hyphen.conf": "{\"a\":\"-foo\"}",
-    "unquoted-strings/022-digit-then-exponent-letter-illegal.conf": "{\"a\":\"1e\"}"
+    "unquoted-strings/022-digit-then-exponent-letter-illegal.conf": "{\"a\":\"1e\"}",
+    "unquoted-strings/025-digit-initial-invalid-number.conf": "{\"a\":\"1.2.3\"}"
   },
   "failures": [
     {
@@ -2057,7 +2059,7 @@
         "a": "null bar"
       },
       "got": {
-        "a": "<pyhocon.config_tree.NoneValue object at 0x103471910>bar"
+        "a": "<pyhocon.config_tree.NoneValue object at 0x102093790>bar"
       }
     },
     {

conformance/reports/pyhocon.spec.json

@@ -4,11 +4,11 @@
   "version": "pyhocon 0.3.63",
   "mode": "spec",
   "command": "conformance/adapters/oracle.sh hocon-py",
-  "ran_at": "2026-10-19T06:02:11Z",
-  "suite_digest": "cd4bdae3133b2042",
-  "total": 445,
+  "ran_at": "2026-10-22T19:38:06Z",
+  "suite_digest": "e05749cb283ceff4",
+  "total": 446,
   "passed": 314,
-  "percent": 70.6,
+  "percent": 70.4,
   "sections": {
     "array-and-object-concatenation": {
       "total": 19,
@@ -135,7 +135,7 @@
       "passed": 5
     },
     "unquoted-strings": {
-      "total": 24,
+      "total": 25,
       "passed": 16
     },
     "value-concatenation": {
@@ -578,6 +578,7 @@
     "unquoted-strings/022-digit-then-exponent-letter-illegal.conf": "fail",
     "unquoted-strings/023-unquoted-string-ends-at-end-of-file.conf": "pass",
     "unquoted-strings/024-escape-sequence-in-unquoted-string-illegal.conf": "fail",
+    "unquoted-strings/025-digit-initial-invalid-number.conf": "fail",
     "value-concatenation/001-simple-values-concatenate-to-string.conf": "pass",
     "value-concatenation/004-string-concatenation-allowed-in-field-keys.conf": "pass",
     "whitespace/001-nonbreaking-space-as-whitespace.conf": "fail",
@@ -638,7 +639,8 @@
     "unchanged-from-json/013-trailing-dot-before-exponent-illegal.conf": "{\"a\":\"-1.e3\"}",
     "unchanged-from-json/014-negative-leading-zeros-illegal.conf": "{\"a\":-33}",
     "unquoted-strings/012-unquoted-cannot-start-with-hyphen.conf": "{\"a\":\"-foo\"}",
-    "unquoted-strings/022-digit-then-exponent-letter-illegal.conf": "{\"a\":\"1e\"}"
+    "unquoted-strings/022-digit-then-exponent-letter-illegal.conf": "{\"a\":\"1e\"}",
+    "unquoted-strings/025-digit-initial-invalid-number.conf": "{\"a\":\"1.2.3\"}"
   },
   "failures": [
     {
@@ -1796,7 +1798,7 @@
         "a": "null bar"
       },
       "got": {
-        "a": "<pyhocon.config_tree.NoneValue object at 0x100ff5910>bar"
+        "a": "<pyhocon.config_tree.NoneValue object at 0x1020af790>bar"
       }
     },
     {
@@ -2136,6 +2138,14 @@
       "expected": "rejected",
       "got": "{\"a\":\"caf\\\\u00e9\"}"
     },
+    {
+      "case": "unquoted-strings/025-digit-initial-invalid-number.conf",
+      "spec": "HOCON.md#unquoted-strings",
+      "rule": "an unquoted string may not begin with the digits 0-9, and the initial number character plus any valid-in-JSON number characters that follow it must be parsed as a number value -- 1.2.3 is that run, and it is not a number, so the input is rejected rather than read as a string (the everyday shape is an address like 127.0.0.1); typesafe/config and pyhocon both fall back to the unquoted string \"1.2.3\"",
+      "expected": "rejected",
+      "got": "{\"a\":\"1.2.3\"}",
+      "java": "lenient"
+    },
     {
       "case": "whitespace/001-nonbreaking-space-as-whitespace.conf",
       "spec": "HOCON.md#whitespace",

conformance/reports/zig-hocon.java.json

@@ -1,15 +1,15 @@
 {
   "suite": "hocon-conformance",
   "implementation": "zig-hocon",
-  "version": "zig-hocon code@20663cc",
+  "version": "zig-hocon code@031f68c",
   "mode": "java",
   "java_version": "1.4.9",
   "command": "conformance/adapters/zig-hocon.sh",
-  "ran_at": "2026-10-19T20:48:55Z",
-  "suite_digest": "cd4bdae3133b2042",
-  "total": 445,
+  "ran_at": "2026-10-22T19:44:29Z",
+  "suite_digest": "e05749cb283ceff4",
+  "total": 446,
   "passed": 401,
-  "percent": 90.1,
+  "percent": 89.9,
   "sections": {
     "array-and-object-concatenation": {
       "total": 19,
@@ -136,7 +136,7 @@
       "passed": 6
     },
     "unquoted-strings": {
-      "total": 24,
+      "total": 25,
       "passed": 22
     },
     "value-concatenation": {
@@ -579,6 +579,7 @@
     "unquoted-strings/022-digit-then-exponent-letter-illegal.conf": "fail",
     "unquoted-strings/023-unquoted-string-ends-at-end-of-file.conf": "pass",
     "unquoted-strings/024-escape-sequence-in-unquoted-string-illegal.conf": "pass",
+    "unquoted-strings/025-digit-initial-invalid-number.conf": "fail",
     "value-concatenation/001-simple-values-concatenate-to-string.conf": "pass",
     "value-concatenation/004-string-concatenation-allowed-in-field-keys.conf": "pass",
     "whitespace/001-nonbreaking-space-as-whitespace.conf": "pass",
@@ -639,7 +640,8 @@
     "unchanged-from-json/013-trailing-dot-before-exponent-illegal.conf": "rejected",
     "unchanged-from-json/014-negative-leading-zeros-illegal.conf": "rejected",
     "unquoted-strings/012-unquoted-cannot-start-with-hyphen.conf": "rejected",
-    "unquoted-strings/022-digit-then-exponent-letter-illegal.conf": "rejected"
+    "unquoted-strings/022-digit-then-exponent-letter-illegal.conf": "rejected",
+    "unquoted-strings/025-digit-initial-invalid-number.conf": "rejected"
   },
   "failures": [
     {
@@ -1226,6 +1228,16 @@
       },
       "got": "rejected (exit 1)",
       "java": "lenient"
+    },
+    {
+      "case": "unquoted-strings/025-digit-initial-invalid-number.conf",
+      "spec": "HOCON.md#unquoted-strings",
+      "rule": "an unquoted string may not begin with the digits 0-9, and the initial number character plus any valid-in-JSON number characters that follow it must be parsed as a number value -- 1.2.3 is that run, and it is not a number, so the input is rejected rather than read as a string (the everyday shape is an address like 127.0.0.1); typesafe/config and pyhocon both fall back to the unquoted string \"1.2.3\"",
+      "expected": {
+        "a": "1.2.3"
+      },
+      "got": "rejected (exit 1)",
+      "java": "lenient"
     }
   ]
 }