Add open-ended bc-version range shorthand [N..]

A closed range like [23..28] wrongly implies guidance stops applying after
BC28, so a reviewer targeting BC29+ would not match the file. Introduce an
open-ended shorthand [N..] meaning ''version N and every later version''.

- validate_frontmatter.py: RANGE_SHORTHAND allows an optional upper bound;
  expand_bc_version returns the normalized string ''N..'' for open-ended.
- read.md: document the fourth bc-version form and its matching rule
  (matches target >= N; not enumerable).
- write.md: prefer [N..] over a closed range for a feature introduced in N
  and not expected to be removed.
- Apply [23..] to the actionable-errors article (actionable errors shipped
  in BC23 and are not version-bounded above).
- README: mention [N..] in the frontmatter example.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

.github/scripts/validate_frontmatter.py

@@ -59,7 +59,7 @@ MAX_KNOWLEDGE_LINES = 100
 
 KEBAB_CASE = re.compile(r"^[a-z0-9]+(-[a-z0-9]+)*$")
 ISO_ALPHA2 = re.compile(r"^[a-z]{2}$")
-RANGE_SHORTHAND = re.compile(r"^(\d+)\.\.(\d+)$")
+RANGE_SHORTHAND = re.compile(r"^(\d+)\.\.(\d+)?$")
 FENCED_CODE_BLOCK = re.compile(r"^```", re.MULTILINE)
 HEADING_H2 = re.compile(r"^##\s+(.+?)\s*$", re.MULTILINE)
 
@@ -149,6 +149,8 @@ def expand_bc_version(value: Any) -> tuple[list[int] | str | None, str | None]:
     """Return (expanded, error-message). One of the two is None.
 
     For the universal sentinel ["all"], `expanded` is the string "all".
+    For an open-ended range like ["26.."], `expanded` is the normalized
+    string "26.." (it cannot be enumerated; consumers match target >= 26).
     Otherwise it is the expanded list of version integers.
     """
     if not isinstance(value, list) or not value:
@@ -163,15 +165,19 @@ def expand_bc_version(value: Any) -> tuple[list[int] | str | None, str | None]:
         if any(v <= 0 for v in value):
             return None, "integers must be positive"
         return sorted(set(value)), None
-    # Case 2: single-element range-shorthand like "[26..28]"
+    # Case 2: single-element range shorthand — closed "[26..28]" or open-ended "[26..]"
     if len(value) == 1 and isinstance(value[0], str):
         m = RANGE_SHORTHAND.match(value[0].strip())
         if m:
-            start, end = int(m.group(1)), int(m.group(2))
+            start = int(m.group(1))
+            if m.group(2) is None:
+                # Open-ended: "start.." applies from start onwards, no upper bound.
+                return f"{start}..", None
+            end = int(m.group(2))
             if start > end:
                 return None, f"range '{value[0]}' is not ascending"
             return list(range(start, end + 1)), None
-    return None, "must be [all], a list of integers, or a single-element range shorthand like [26..28]"
+    return None, "must be [all], a list of integers, or a range shorthand like [26..28] or [26..]"
 
 
 def headings_in_order(body: str) -> list[tuple[str, int]]:

README.md

@@ -72,7 +72,7 @@ Every knowledge file is a markdown file with mandatory YAML frontmatter. Files t
 
 ```yaml
 ---
-bc-version: [all]                       # or [26..28] for version-gated guidance
+bc-version: [all]                       # or [26..28], or [26..] for "26 and later"
 domain: performance                     # security | performance | ux | telemetry | ...
 keywords: [query, filtering, partial]   # free-text tags for retrieval
 technologies: [al]                      # al | javascript | powershell | ...

microsoft/knowledge/error-handling/prefer-errorinfo-for-actionable-errors.md

@@ -1,5 +1,5 @@
 ---
-bc-version: [23..28]
+bc-version: [23..]
 domain: error-handling
 keywords: [errorinfo, actionable-errors, fix-it, show-it, addaction, addnavigationaction, error-dialog]
 technologies: [al]

skills/read.md

@@ -26,7 +26,7 @@ A file that violates any of these rules is invalid and MUST be skipped by consum
 
 ```yaml
 ---
-bc-version: [all]                       # or [26, 27, 28] or the range shorthand [26..28]
+bc-version: [all]                       # or [26, 27, 28], the range [26..28], or the open-ended range [26..]
 domain: performance
 keywords: [query, filtering, partial]
 technologies: [al]
@@ -39,13 +39,14 @@ All six fields are required. Missing or empty fields invalidate the file.
 
 ### Fields
 
-**`bc-version`** — Array. The Business Central major versions this file applies to. Three forms are accepted:
+**`bc-version`** — Array. The Business Central major versions this file applies to. Four forms are accepted:
 
 - Universal sentinel: `[all]` means the guidance applies to every BC version and matches any target.
 - Explicit list: `[26, 27, 28]`.
-- Range shorthand: `[26..28]` means every integer from 26 through 28 inclusive.
+- Closed range shorthand: `[26..28]` means every integer from 26 through 28 inclusive.
+- Open-ended range shorthand: `[26..]` means version 26 and every later version, with no upper bound. Use it for guidance tied to a feature introduced in a specific version that is not expected to be removed.
 
-`[all]` is mutually exclusive with explicit versions; do not combine. Consumers MUST expand ranges to the full set before comparison.
+`[all]` is mutually exclusive with explicit versions; do not combine. Consumers MUST expand closed ranges to the full set before comparison; an open-ended range `[N..]` is not enumerable and instead matches any target version greater than or equal to `N`.
 
 **`domain`** — String. A single domain tag that places the file within a broader area of concern. Standard values include `performance`, `security`, `ux`, `telemetry`, `testing`, `api`, `pipelines`, `finance`, `supply-chain`, `manufacturing`, `jobs`. New domains may be introduced by contributors; no closed enumeration is enforced at the schema level. Consumers MUST treat unknown domains as valid.
 
@@ -94,7 +95,7 @@ Conflict detection is the consumer's responsibility; BCQuality does not enforce
 
 When a consumer filters or matches files against a task context, these rules apply:
 
-- **`bc-version`** — the file matches if its set is `[all]`, or if the target BC version is an element of the file's expanded `bc-version` set. Range shorthand (`[26..28]`) MUST be expanded before comparison.
+- **`bc-version`** — the file matches if its set is `[all]`, or if the target BC version is an element of the file's expanded `bc-version` set. Closed range shorthand (`[26..28]`) MUST be expanded before comparison; an open-ended range (`[26..]`) matches when the target BC version is greater than or equal to its lower bound.
 - **`technologies`** — non-empty intersection between the task's technologies and the file's technologies. There is no sentinel for this field.
 - **`countries`** — the file matches if its set contains `w1`, or if there is a non-empty intersection with the task's countries.
 - **`application-area`** — the file matches if its set contains `all`, or if there is a non-empty intersection with the task's application areas.

skills/write.md

@@ -43,7 +43,7 @@ Knowledge files do not contain code. Samples live as **sibling files** next to t
 
 ## Choosing frontmatter values
 
-**`bc-version`.** Default to `[all]` when the guidance is universal — a BC language pattern, a property on a long-standing platform type, a CodeCop rule, or a platform behaviour that has not changed across versions. Use an explicit list or range (`[26, 27, 28]`, `[26..28]`) only when the guidance is tied to a version-gated API, a deprecation, or platform behaviour that genuinely differs across versions. Most knowledge files should be `[all]`; reach for a range only with a concrete reason.
+**`bc-version`.** Default to `[all]` when the guidance is universal — a BC language pattern, a property on a long-standing platform type, a CodeCop rule, or a platform behaviour that has not changed across versions. Use an explicit list or range (`[26, 27, 28]`, `[26..28]`) only when the guidance is tied to a version-gated API, a deprecation, or platform behaviour that genuinely differs across versions. When guidance applies to a feature introduced in version N and not expected to be removed, prefer the open-ended range `[N..]` over a closed range so the file keeps matching future versions — reserve a closed upper bound for guidance that genuinely stops applying (for example, a behaviour removed or replaced in a later version). Most knowledge files should be `[all]`; reach for a range only with a concrete reason.
 
 **`domain`.** Pick one. If two fit, the file is probably two concerns. If no existing domain fits, introduce a new one — domains are open. Prefer existing domains when they are a reasonable fit, to keep retrieval predictable.