Fix incorrect formatting for comments inside multi-line argument lists and method chains #1929

Copilot · 2025-10-22T18:28:23Z

Problem

The formatter was incorrectly removing indentation from comments inside multi-line argument lists and chained method calls. This caused comments to be flush with the left margin instead of maintaining their proper indentation level, and in some cases caused a panic with "strings: negative Repeat count".

Example 1: Multi-line argument list

// Before (incorrect)
console.log(
	"a",
// the second arg  ← Lost indentation!
	"b"
);

// After (correct)
console.log(
	"a",
	// the second arg  ← Indentation preserved!
	"b"
);

Example 2: Chained method calls

// Before (incorrect - caused panic)
foo
	.bar()
// A second call  ← Lost indentation!
	.baz();

// After (correct)
foo
	.bar()
	// A second call  ← Indentation preserved!
	.baz();

Root Cause

The getIndentationForComment function in internal/format/span.go was not using the tokenIndentation parameter passed to it. This parameter contains the calculated indentation for the token that follows the comment. When available (not -1), it should be used instead of the base indentation level.

The TypeScript reference implementation at _submodules/TypeScript/src/services/formatting/formatting.ts:704 includes this check:

return tokenIndentation !== Constants.Unknown ? tokenIndentation : indentation;

But the Go port was missing this logic, always returning the base indentation regardless of the token-specific indentation. When tokenIndentation was -1, it was passed directly to the indentation string generation, causing a panic in strings.Repeat.

Solution

Added a check to use tokenIndentation when it's not -1 (the "unknown" sentinel value):

if tokenIndentation != -1 {
    return tokenIndentation
}
return i.indentation

This ensures that comments inherit the indentation of the token they precede, maintaining consistent formatting within multi-line structures.

Testing

Added comprehensive test cases for both reported scenarios
Added explicit regression test for issue Panic formatting chained method call #1928 (panic when formatting chained method calls)
All existing tests continue to pass
Full test suite runs successfully with no regressions

Fixes #1927
Fixes #1928
Fixes #1925

Original prompt

This section details on the original issue you should resolve

<issue_title>Incorrect formatting for comment inside of multi-line argument list</issue_title>
<issue_description>Repo
Format the following file:
console.log(
	"a",
	// the second arg
	"b"
);
Bug
This incorrectly removes the space before the comment, resulting in:
console.log(
	"a",
// the second arg
	"b"
); 
```</issue_description>

<agent_instructions>Create formatting tests first, then examine the code in comparison to _submodules/TypeScript/src/services/formatting/formatting.ts.</agent_instructions>

## Comments on the Issue (you are @copilot in this section)

<comments>
<comment_new><author>@mjbvz</author><body>
Similar issue for chained method calls:

```ts

foo
	.bar()
	// A second call
	.baz(); 
```</body></comment_new>
</comments>

Fixes #1927

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…guments Co-authored-by: jakebailey <[email protected]>

…thod chains Co-authored-by: jakebailey <[email protected]>

Copilot

Pull Request Overview

This PR fixes a formatting bug where comments inside multi-line argument lists and chained method calls were incorrectly losing their indentation. The fix aligns the Go port with the TypeScript reference implementation by checking and using the token-specific indentation value when available.

Key changes:

Added logic to use tokenIndentation when it's not -1 (unknown) in getIndentationForComment
Added two comprehensive test cases verifying comment indentation is preserved in multi-line argument lists and method chains

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
internal/format/span.go	Added check to use token-specific indentation for comments when available
internal/format/comment_test.go	Added tests for comment formatting in multi-line argument lists and chained method calls

jakebailey · 2025-10-22T18:52:07Z

@copilot also add the test for #1928, since the fix in this PR also fixes that issue.

…call) Co-authored-by: jakebailey <[email protected]>

Copilot · 2025-10-22T18:59:36Z

@copilot also add the test for #1928, since the fix in this PR also fixes that issue.

Added regression test for issue #1928 in commit ccd9922. The test explicitly documents that the panic was caused by the same root issue - tokenIndentation being -1 was not being handled correctly.

@typedef

* Port 'go to type definition' tests (microsoft#1883) * Fix panic in `getTokenAtPosition` for JSDoc type assertions (microsoft#1846) Co-authored-by: copilot-swe-agent[bot] <[email protected]> Co-authored-by: jakebailey <[email protected]> Co-authored-by: andrewbranch <[email protected]> Co-authored-by: Andrew Branch <[email protected]> * Don’t look in JSExportAssignment and CommonJSExport for nodes (microsoft#1886) * Fix link in native preview platform packages (microsoft#1838) * fix(1880): No error message for JSDoc type parsing (microsoft#1881) * Add vscode editor issue template (microsoft#1893) Co-authored-by: Ryan Cavanaugh <[email protected]> * Add "Report Issue" button to TSGO status bar commands (microsoft#1889) Co-authored-by: copilot-swe-agent[bot] <[email protected]> Co-authored-by: DanielRosenwasser <[email protected]> Co-authored-by: Daniel Rosenwasser <[email protected]> * fix(1898): adjust location handling in find-refs (microsoft#1901) * Fix panic of empty string in type reference directive (microsoft#1908) * Consistently error on full circle of circular import aliases (microsoft#1904) * Fix panic in textDocument/onTypeFormatting when tokenAtPosition is nil (microsoft#1845) Co-authored-by: copilot-swe-agent[bot] <[email protected]> Co-authored-by: jakebailey <[email protected]> * Update submodule (microsoft#1913) * Disable create-cache.yml in forks (microsoft#1912) * Forbid platform specific package uses in agnostic files (microsoft#1911) * Fix JSDoc comment formatting with tab indentation (microsoft#1900) Co-authored-by: copilot-swe-agent[bot] <[email protected]> Co-authored-by: jakebailey <[email protected]> * Clear local baseline dir in hereby test (microsoft#1921) * Unskip passing fourslash test (microsoft#1922) * Support auto-import completion fourslash tests, fix bugs (microsoft#1917) * Fix JSX indentation in JavaScript output (microsoft#1792) Co-authored-by: copilot-swe-agent[bot] <[email protected]> Co-authored-by: jakebailey <[email protected]> * Implement printAllHelp to fix `tsgo --all` producing no output (microsoft#1843) Co-authored-by: copilot-swe-agent[bot] <[email protected]> Co-authored-by: jakebailey <[email protected]> * Bump the github-actions group across 1 directory with 2 updates (microsoft#1909) Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Co-authored-by: Jake Bailey <[email protected]> * Ensure os package is forbidden in lint (microsoft#1924) * Speed up levenshteinWithMax by reusing buffers (microsoft#1823) * Fix incorrect formatting for comments inside multi-line argument lists and method chains (microsoft#1929) Co-authored-by: copilot-swe-agent[bot] <[email protected]> Co-authored-by: jakebailey <[email protected]> * Handle nil end position in getMappedLocation (microsoft#1920) * Fix formatter adding extra space at end of line without trailing newline (microsoft#1933) Co-authored-by: copilot-swe-agent[bot] <[email protected]> Co-authored-by: jakebailey <[email protected]> * Fix vscode issue template (microsoft#1934) * userpreferences parsing/ls config handing (microsoft#1729) * Plumb through TokenFlagsSingleQuote; use for auto import quote detection (microsoft#1937) * Invalidate caches on batches of 1000+ watch changes (microsoft#1869) * Create clickable links in quick info from @link JSDoc tags (microsoft#1935) * Don't report errors on `{@link foo.bar}` references (microsoft#1941) * Fix crash in `invocationErrorRecovery` function (microsoft#1944) * Fix leading source file comment emit bugs (microsoft#1945) * Implement selection ranges (microsoft#1939) * Fix porting bug in isArgumentAndStartLineOverlapsExpressionBeingCalled (microsoft#1948) * Add Range to Hover (microsoft#1489) Co-authored-by: copilot-swe-agent[bot] <[email protected]> Co-authored-by: DanielRosenwasser <[email protected]> Co-authored-by: Jake Bailey <[email protected]> * Properly handle hovering on `this` (microsoft#1953) * Bump the github-actions group across 1 directory with 2 updates (microsoft#1959) Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> * Fixed document highlight for reference directive (microsoft#1951) * Several fixes to JS typing of functions and methods (microsoft#1960) * Update submodule, port 6.0 options defaults (microsoft#1961) * Reapply microsoft#1951 and microsoft#1960 after bad merge (microsoft#1964) Co-authored-by: Anders Hejlsberg <[email protected]> Co-authored-by: John Favret <[email protected]> * Update submodule with ES5 removals (microsoft#1963) * Actually transform KindCommonJSExport in declaration emit (microsoft#1962) * Quick Info fixes (microsoft#1971) * Fix various named enum types (microsoft#1973) * Move change tracker, converters, utils to separate packages (microsoft#1977) * Consistent rules for mixing `@type`, `@param`, `@return`, `@template` (microsoft#1979) * Check for identifier before obtaining text of name (microsoft#1984) * Respect client capabilities for diagnostics (microsoft#1980) * Store explicitly declared members ahead of inherited members (microsoft#1987) * Add --checkers to control number of checkers per Program (microsoft#1985) * Export all types referenced through other exported APIs, enforce (microsoft#1978) * Switch custom runners from mariner-2.0 to azure-linux-3 (microsoft#1989) * Use `LocationLink` in go to definition (microsoft#1884) * Use a different set of commands to detect fourslash test updates (microsoft#1923) * Skip erasableSyntaxOnly checks for JavaScript files (microsoft#1956) Co-authored-by: copilot-swe-agent[bot] <[email protected]> Co-authored-by: jakebailey <[email protected]> * Update submodule for new cherry-picks (microsoft#1996) * Port TypeScript PR #62604: Propagate variance reliability (microsoft#1916) Co-authored-by: copilot-swe-agent[bot] <[email protected]> Co-authored-by: RyanCavanaugh <[email protected]> Co-authored-by: Jake Bailey <[email protected]> * Only export `@typedef` type aliases in modules (microsoft#1999) * Bump github/codeql-action from 4.31.0 to 4.31.2 in the github-actions group across 1 directory (microsoft#2005) Signed-off-by: dependabot[bot] <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> * Hoist @typedef and @import tags to containing scopes that permit them (microsoft#2003) * Remove concept of "unsupported extensions", clean up test skips (microsoft#2004) * Update golangci-lint, fix issues, modernize (microsoft#1981) * Implement more handling of client capabilities (microsoft#1998) * Add docs to signature help (microsoft#2009) Co-authored-by: Copilot <[email protected]> * Fix unused identifier diags, LSP tag diags (microsoft#2007) * fix(2015): abstract property created, overshadowing override (microsoft#2016) * Always check refCount after acquiring lock (microsoft#1986) * Delete resolver unit tests (microsoft#2008) * Fix missing parent for `Expression` in `TypeParameterDeclaration` (microsoft#2017) * Add missing nil check in `getCompletionItemActions` (microsoft#2018) * Fix crash in find-all-refs on `exports.xxx` in .js file (microsoft#2023) * Properly include JSX attributes in find-all-references (microsoft#2025) * Fix crash by removing `getNameFromImportDeclaration` in favor of `Node.Name()` (microsoft#2027) * Fix losing options from command line in watch mode (microsoft#2024) * Add issue investigator agent (microsoft#2030) * Switch 1ESPT pipelines to 1ESPT-AzureLinux3 (microsoft#2031) * Port inlay hints (microsoft#1705) * Split "use strict" into separate transformer, fix bugs with prologues (microsoft#2028) Co-authored-by: Sheetal Nandi <[email protected]> * Use a more cross-architecture-friendly devcontainer image. (microsoft#2034) * Fix nil pointer dereference in range formatting (microsoft#1993) Co-authored-by: copilot-swe-agent[bot] <[email protected]> Co-authored-by: DanielRosenwasser <[email protected]> Co-authored-by: jakebailey <[email protected]> Co-authored-by: Daniel Rosenwasser <[email protected]> Co-authored-by: Copilot <[email protected]> * Port missing `checkJs` logic (microsoft#2046) * Ignore reparsed nodes when determining external module indicator (microsoft#2044) * Fix various fuzzer-caught crashes in the parser (microsoft#2038) * Fix moduleDetection for node18, fix __esModule in detect=force (microsoft#2045) * Fix panic in syncmap on loading nil (microsoft#2056) * Use accessors on `Node` instead of casts and field accesses (microsoft#2052) * Add locks on concurrent alias following checker accesses under incremental mode (microsoft#2051) * Don't add `export` modifier to `JSTypeAliasDeclaration` from `@callback` (microsoft#2063) * Introduce GetECMALineOfPosition to avoid unused rune counting (microsoft#2065) * Don't add `export` modifier to `KindCommonJSExport` reparsed nodes (microsoft#2066) * Fix panic in inlay hints for tuple types (microsoft#2040) Co-authored-by: copilot-swe-agent[bot] <[email protected]> Co-authored-by: jakebailey <[email protected]> * Accurately recognize fourslash test as submodule (microsoft#2068) * Implement auto-import code actions, port tests and fix some bugs (microsoft#2053) * Port tsc --init (microsoft#2033) * Make CheckerPool iteration concurrent by default (microsoft#2070) * Use Microsoft build of Go in CI (microsoft#2069) * Detect Windows junctions with GetFileAttributesEx (microsoft#2013) * Fix CI cache workflow (microsoft#2071) * Use information from contextual type in hovers/quick info (microsoft#2073) * fix(2074): No quick info on function and other similar tokens (microsoft#2078) * Unify locks used on checkers between exclusive pool borrows and EmitResolver scopes (microsoft#2080) * Port non-baseline diagnostics tests (microsoft#2079) * Use SkipTrivia instead of GetRangeOfTokenAtPosition where possible (microsoft#2089) * Move unreachable checks to checker, allowing more AST reuse (microsoft#2067) * Fix scanning of valid surrogate pairs (microsoft#2032) * Fix misplaced parentheses in `Checker.isIndirectCall` (microsoft#2093) * Various agent mode updates (microsoft#2094) * Handle configuration changes in LSP for 'typescript.*' options. (microsoft#2088) * Fix nil pointer dereference in getAdjustedLocation for type-only exports (microsoft#2090) Co-authored-by: copilot-swe-agent[bot] <[email protected]> Co-authored-by: jakebailey <[email protected]> * Fix nil pointer dereference in code actions when diagnostic code is nil (microsoft#2091) Co-authored-by: copilot-swe-agent[bot] <[email protected]> Co-authored-by: jakebailey <[email protected]> * Fully resolve LSP client caps to non-pointers, pass by context (microsoft#2095) * Fix hover on `module.exports` (microsoft#2098) * Accept and document jsdoc diffs, round 1 (microsoft#1426) Co-authored-by: Copilot <[email protected]> Co-authored-by: Jake Bailey <[email protected]> * Port baseline diagnostics tests (microsoft#2097) * Clean up disk space in CI before running (microsoft#2103) Co-authored-by: Copilot <[email protected]> * Add GOBIN to PATH in CI (microsoft#2105) * Make client requests type safe, unmarshal (microsoft#2099) * Display inherited JSDoc documentation in quick info (microsoft#2111) * Sort failingTests and manualTests in en-US (microsoft#2113) * fix(2047): Incomplete declaration emit of callback tag with no return tag (microsoft#2100) * Fix canHaveSyntheticDefault (microsoft#2101) * Misc fixes (microsoft#2112) * chore: fix incorrect function name in comment (microsoft#2109) Signed-off-by: weifangc <[email protected]> * Fix typedef binding with CJS `exports=` (microsoft#826) * Provide Program diagnostics as push diags in tsconfig.json (microsoft#2118) Co-authored-by: Copilot <[email protected]> * Update dependencies (microsoft#2116) * Remove copilot-setup-steps env var (microsoft#2124) * Fix panic on negative parameterIndex in type predicate flow analysis (microsoft#2122) Co-authored-by: copilot-swe-agent[bot] <[email protected]> Co-authored-by: RyanCavanaugh <[email protected]> Co-authored-by: Ryan Cavanaugh <[email protected]> * Port tests for go to implementation and diff definitions tests (microsoft#2130) * Partially fix multi-checker diagnostics consistency (microsoft#2134) * Implement reportStyleChecksAsWarnings (microsoft#2132) * Include docs on resolved client caps (microsoft#2135) * Fix dynamic import grammar check (microsoft#2138) * Refine LSP with our own types, generate more stuff (microsoft#2141) * Display all symbol meanings in quick info (microsoft#2144) * Multiproject requests like find all refs, rename and workspace symbols (microsoft#1991) * Add stringer-alike String methods to non-string LSP enums (microsoft#2148) * Enable localization (microsoft#2123) * Port workspace symbols tests (microsoft#2146) * Update readme, issue template (microsoft#2140) * Ignore config port (microsoft#1755) * fix(2157): jsdocfunction param is inferred as implicit any when directly assigned to module.exports (microsoft#2158) * fixes after merge * some more fixes * more errors * builds * fmt * fix nil pointer deref * fix error messages --------- Signed-off-by: dependabot[bot] <[email protected]> Signed-off-by: weifangc <[email protected]> Co-authored-by: Gabriela Araujo Britto <[email protected]> Co-authored-by: Copilot <[email protected]> Co-authored-by: jakebailey <[email protected]> Co-authored-by: andrewbranch <[email protected]> Co-authored-by: Andrew Branch <[email protected]> Co-authored-by: Andrew Branch <[email protected]> Co-authored-by: Oleksandr T. <[email protected]> Co-authored-by: Matt Bierner <[email protected]> Co-authored-by: Ryan Cavanaugh <[email protected]> Co-authored-by: DanielRosenwasser <[email protected]> Co-authored-by: Daniel Rosenwasser <[email protected]> Co-authored-by: Twacqwq <[email protected]> Co-authored-by: Anders Hejlsberg <[email protected]> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Co-authored-by: Isabel Duan <[email protected]> Co-authored-by: John Favret <[email protected]> Co-authored-by: Wesley Wigham <[email protected]> Co-authored-by: RyanCavanaugh <[email protected]> Co-authored-by: Copilot <[email protected]> Co-authored-by: xu0o0 <[email protected]> Co-authored-by: Sheetal Nandi <[email protected]> Co-authored-by: Nathan Shively-Sanders <[email protected]> Co-authored-by: weifangc <[email protected]> Co-authored-by: Ryan Cavanaugh <[email protected]> Co-authored-by: Nathan Whitaker <[email protected]>

Initial plan

319ed2d

Copilot AI assigned Copilot and jakebailey Oct 22, 2025

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Copilot AI and others added 2 commits October 22, 2025 18:38

Add test to reproduce formatting issue with comments in multi-line ar…

652cf74

…guments Co-authored-by: jakebailey <[email protected]>

Fix incorrect comment indentation in multi-line argument lists and me…

3e7ab19

…thod chains Co-authored-by: jakebailey <[email protected]>

Copilot AI changed the title ~~[WIP] Fix incorrect formatting for comments in multi-line argument lists~~ Fix incorrect formatting for comments inside multi-line argument lists and method chains Oct 22, 2025

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[WIP] Fix panic in formatting chained method call #1930

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Add regression test for issue #1928 (panic formatting chained method …

ccd9922

…call) Co-authored-by: jakebailey <[email protected]>

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Fix panic in textDocument/formatting with slice bounds out of range #1931

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Add test from 1931

508b55b

Drop contains helper

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Fix incorrect formatting for comments inside multi-line argument lists and method chains #1929

Fix incorrect formatting for comments inside multi-line argument lists and method chains #1929

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edited by jakebailey

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Fix incorrect formatting for comments inside multi-line argument lists and method chains #1929

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