extract _parse_tool_version helper for black --version parsing by HrachShah · Pull Request #762 · microsoft/vscode-black-formatter

HrachShah · 2026-06-18T11:49:54Z

_update_workspace_settings_with_version_info inlined a fragile regex match against the first line of the tool's --version output. If the line was empty, splitlines() raised IndexError and the whole initialization crashed. If the first line had no version token, or had multiple (e.g. a CPython banner like 'Python 3.12.0'), the code defaulted to the literal string '0.0.0' which is a valid (very old) SemVer and silently passes the >= 22.3.0 check while logging a misleading 'NOT supported' line for every workspace.

This commit pulls the regex match out into _parse_tool_version(stdout) and calls it from the version detection loop with proper ValueError handling: empty stdout -> 'empty --version output'; no candidate -> 'no version candidate in --version output: '. When the first line has multiple version-shaped tokens, the helper picks the longest so a real '24.3.0' or '24.3.0rc1' wins over a stray short match in a Python banner.

Also tightens the regex from \d+.\d+\S* to \d+.\d+(?:.\d+)?\S* fullmatch, so a bare '24.3' is accepted (some dev installs drop the patch number) without matching '24.3.0' twice on a '24.3.0rc1' line.

Added bundled/tool/tests/test_parse_tool_version.py with 9 unit tests covering: standard 'black, 24.3.0' output, pre-release '24.3.0rc1', multiple version tokens on the first line, CRLF line endings, empty stdout, whitespace-only first line, missing version token, two-part version '24.3', and confirms the helper uses the first line only.

… helper _update_workspace_settings_with_version_info inlined a fragile regex match against the first line of the tool's --version output: \d+\.\d+\S*. If the line was empty (splitlines() raises IndexError) the whole initialization crashed; if the first line had no version token, or had multiple (e.g. a CPython banner like 'Python 3.12.0'), the code defaulted to the literal string '0.0.0' which is a valid (very old) SemVer and silently passes the >= 22.3.0 check while logging a misleading 'NOT supported' line for every workspace. Pull the regex match out into _parse_tool_version(stdout) and call it from the version detection loop with proper ValueError handling: empty stdout -> 'empty --version output'; no candidate -> 'no version candidate in --version output: <line>'. When the first line has multiple version-shaped tokens, pick the longest so a real '24.3.0' or '24.3.0rc1' wins over a stray short match in a Python banner. The previous code only kept a match when len(parts) == 1, silently dropping valid versions whenever the line had any other version-shaped text. Added bundled/tool/tests/test_parse_tool_version.py with 9 unit tests: standard black output 'black, 24.3.0', pre-release '24.3.0rc1', multiple candidates, CRLF line endings, empty stdout, whitespace-only first line, missing version token, two-part version '24.3', and confirms the helper uses the first line only.

edvilme · 2026-06-20T00:00:34Z

Danke shon! @HrachShah
Thanks for the contribution. There are some merge conflicts, but otherwise looks good to me! :)

rchiodo · 2026-06-23T17:50:04Z

+    def test_handles_two_part_version(self):
+        out = "black, 24.3\n"
+        assert _parse_tool_version(out) == "24.3"
+


📍 bundled/tool/tests/test_parse_tool_version.py:52
Confirmed violation of tests-no-partial-asserts.md: test_raises_on_whitespace_only_output and test_raises_when_no_version_token use match="no version candidate", a partial regex, against fully deterministic exception messages. The inputs are hardcoded constants, so the full message is fixed and must be asserted exactly: match=r"no version candidate in --version output: '\s*'" and match=r"no version candidate in --version output: 'something went wrong'". (test_raises_on_empty_output already uses a full match and is fine.)

rchiodo · 2026-06-23T17:50:07Z

+    # If the first line contains multiple version-shaped tokens (e.g. black
+    # with an embedded 'X.Y.Z' and '24.3.0'), pick the longest so a
+    # pre-release suffix like '24.3.0rc1' wins over a stray short match.
+    return max(parts, key=len)


📍 bundled/tool/lsp_server.py:348
max(parts, key=len) picks the wrong token on a same-length tie: _parse_tool_version("Python 3.12.0 black, 24.3.0") returns "3.12.0", not 24.3.0, because max returns the first maximum. The PR's multi-token test only passes because rc1 makes black's token coincidentally longer — the test is tuned to the heuristic, not the real format. Reachability is low (black emits a single version token on line 1), so this is not a blocker, but consider anchoring on the format instead — e.g. the first token that fullmatches after black, — and retargeting the test.

rchiodo · 2026-06-23T17:50:10Z

+        # A second line that contains a version is ignored; we only look
+        # at the first line because that's where tools emit their banner.
+        out = "black, 24.3.0\nsome other 1.2.3.4 token\n"
+        assert _parse_tool_version(out) == "24.3.0"


📍 bundled/tool/tests/test_parse_tool_version.py:1
The tests exercise _parse_tool_version in isolation only. The PR's most consequential behavioral change — the new continue skipping VERSION_LOOKUP population and the resulting potential KeyError in range formatting — has no integration coverage. A unit test of the helper can never catch this. Consider adding a test that drives the version-detection loop with unparseable --version output and then asserts range formatting still degrades gracefully rather than raising.

rchiodo · 2026-06-23T17:50:13Z

+    # If the first line contains multiple version-shaped tokens (e.g. black
+    # with an embedded 'X.Y.Z' and '24.3.0'), pick the longest so a
+    # pre-release suffix like '24.3.0rc1' wins over a stray short match.
+    return max(parts, key=len)


📍 bundled/tool/lsp_server.py:332
The PR description overstates/misstates the motivation: the old splitlines()[0] IndexError was caught by the surrounding bare except: so initialization did not crash (one workspace was skipped); (0,0,0) >= (22,3,0) is False so the old default logged "NOT supported" rather than silently passing the check; and the old \d+\.\d+\S* regex already matched a bare 24.3, so the (?:\.\d+)? addition doesn't change that case. The refactor still stands on its own merits — please correct the description so future readers trust the rationale. Info-only.

rchiodo · 2026-06-23T17:50:17Z

Refactor looks good and is safe to merge. A few non-blocking notes below: a tie-break edge case in max(parts, key=len), a test-rule nit on partial exception asserts, a missing integration test around the new continue path, and some inaccuracies in the PR description worth correcting.

rchiodo

Approved via Review Center.

rchiodo · 2026-06-25T18:57:00Z

Solid refactor with good unit coverage. One non-blocking note on the version-token selection heuristic; the remaining first-pass items were either test-style nitpicks, an inapplicable internal review rule, or PR-description nits and were dropped.

rchiodo

Approved via Review Center.

edvilme · 2026-06-25T23:25:23Z

Thanks for your contribution @HrachShah !

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rchiodo · 2026-06-30T21:54:37Z

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rchiodo · 2026-06-30T22:06:42Z

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rchiodo · 2026-06-30T22:08:25Z

+    if not parts:
+        raise ValueError(f"no version candidate in --version output: {lines[0]!r}")
+    # If the first line contains multiple version-shaped tokens (e.g. black
+    # with an embedded 'X.Y.Z' and '24.3.0'), pick the longest so a


📍 bundled/tool/lsp_server.py:308
The max(parts, key=len) disambiguation is unsound — the Skeptic and Architect both verified by execution that it picks the wrong token: 'Python 3.12.0 black, 24.3.0' returns '3.12.0' (Python's version, equal length → first wins), and 'black, 24.3.0 built 2024.10' returns '2024.10', which then falsely passes >= 22.3.0. The author's own passing test only works because 24.3.0rc1 (len 9) coincidentally beats 3.12.0 (len 6). black's format is positionally stable (black, X.Y.Z …); disambiguate by structure — take the token immediately following the tool name, or the first matching token — and validate it via parse_version before returning.

[verified]

rchiodo · 2026-06-30T22:08:28Z

+                log_error(
+                    f"Could not parse version of formatter running for "
+                    f"{code_workspace}: {ve}\r\n"
+                )


📍 bundled/tool/lsp_server.py:339
version = parse_version(actual_version) is outside the new try/except ValueError. The Skeptic verified that a malformed-but-fullmatch-ing token (e.g. 'black, 24.3.0 99.99.99,' → longest is '99.99.99,') makes parse_version raise InvalidVersion, which the targeted except ValueError never catches. The Advocate's file read notes an outer bare-except absorbs it, so this isn't a hard init crash — but it bypasses the PR's own diagnostic path and re-introduces the unguarded-parse failure class the PR set out to eliminate. Move parse_version(actual_version) inside the try (catch ValueError, which covers InvalidVersion) and continue on failure.

[verified]

rchiodo · 2026-06-30T22:08:31Z

    tool_server.handle_shutdown()


+VERSION_RE = re.compile(r"\d+\.\d+(?:\.\d+)?\S*")


📍 bundled/tool/lsp_server.py:291
VERSION_RE = r"\d+\.\d+(?:\.\d+)?\S*" — the trailing \S* greedily swallows punctuation into the version token (verified: 'black 24.3.0,' → '24.3.0,'), which then breaks parse_version. This was pre-existing but becomes newly reachable through the multi-token path. Anchor the suffix to plausible version characters (e.g. (?:[abc]|rc|\.dev|\.post|[-+.\w])*) or strip trailing non-word chars before parsing.

[verified]

rchiodo · 2026-06-30T22:08:34Z

+        with pytest.raises(ValueError, match="empty --version output"):
+            _parse_tool_version("")
+
+    def test_raises_on_whitespace_only_output(self):


📍 bundled/tool/tests/test_parse_tool_version.py:41
test_picks_longest_candidate_when_multiple_match cements the flawed "longest wins" heuristic as an invariant — its fixture ('Python 3.12.0 black, 24.3.0rc1') is the one case where longest happens to be correct. A realistic sibling ('Python 3.12.10rc2 black, 24.3.0') breaks it, and none of the tests assert the value on an equal-length or longer-junk-token line. Once the heuristic is fixed to be structure-based, this test must be rewritten to assert the real contract (the token after the tool name).

[verified]

rchiodo · 2026-06-30T22:08:38Z

Main theme: the version token disambiguation is fragile. Prefer structure-based extraction (the token following the tool name) over 'longest wins', and move parse_version(actual_version) inside the new try/except so InvalidVersion is also handled.

rchiodo · 2026-06-30T22:17:27Z

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rchiodo · 2026-07-01T22:18:21Z

🔒 Automated review in progress — @rchiodo is auto-reviewing this PR.

rchiodo · 2026-07-02T22:18:53Z

🔒 Automated review in progress — @rchiodo is auto-reviewing this PR.

edvilme previously approved these changes Jun 20, 2026

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[aw] No-Op Runs #649

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Merge branch 'main' into fix/parse-tool-version-helper

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edvilme added the bug Issue identified by VS Code Team member as probable bug label Jun 25, 2026

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		tool_server.handle_shutdown()


		VERSION_RE = re.compile(r"\d+\.\d+(?:\.\d+)?\S*")

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