Preserve printf-style format substitution when piping server logs to browser console#479
Preserve printf-style format substitution when piping server logs to browser console#479mvanhorn wants to merge 1 commit into
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📝 WalkthroughWalkthroughThe virtual console SSE log renderer in ChangesServer log format-substitution preservation
Estimated code review effort🎯 2 (Simple) | ⏱️ ~10 minutes Poem
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Actionable comments posted: 1
🤖 Prompt for all review comments with AI agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
Inline comments:
In `@packages/devtools-vite/src/virtual-console.ts`:
- Around line 321-324: The preserve-format detection in getConsoleFormatIndex is
too permissive and can treat literal percent text like “100%c” as a format
string when there are no matching substitution arguments. Update the logic
around getConsoleFormatIndex and the related preserve-format path to only
preserve formatting when the number of actual console placeholders is supported
by the available trailing args, so literal % sequences are not reclassified
after prefix injection.
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Fix all unresolved CodeRabbit comments on this PR:
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.changeset/fresh-mails-bow.mdpackages/devtools-vite/src/virtual-console.test.tspackages/devtools-vite/src/virtual-console.ts
| function getConsoleFormatIndex(args) { | ||
| if (hasConsoleFormatSubstitution(args[0])) return 0; | ||
| return isEnhancedLogPrefix(args[0]) && hasConsoleFormatSubstitution(args[1]) ? 1 : -1; | ||
| } |
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🎯 Functional Correctness | 🟠 Major | ⚡ Quick win
Avoid classifying literal % sequences as format substitutions.
getConsoleFormatIndex currently enables the preserve-format branch even when there are no substitution arguments. Literal messages like "CPU at 100%c" can then be treated as format strings and rendered incorrectly after prefix injection. Gate preservation by placeholder count vs available trailing args.
Suggested fix
- function hasConsoleFormatSubstitution(arg) {
- return typeof arg === 'string' && /(^|[^%])%[sdifocOj]/.test(arg);
- }
+ function getConsoleFormatPlaceholderCount(arg) {
+ if (typeof arg !== 'string') return 0;
+ var matches = arg.match(/(^|[^%])%[sdifocOj]/g);
+ return matches ? matches.length : 0;
+ }
function isEnhancedLogPrefix(arg) {
return typeof arg === 'string' &&
arg.indexOf('LOG') !== -1 &&
arg.indexOf(String.fromCharCode(10) + ' ' + String.fromCharCode(8594) + ' ') !== -1;
}
+ function hasResolvableConsoleFormatSubstitution(args, formatIndex) {
+ var placeholderCount = getConsoleFormatPlaceholderCount(args[formatIndex]);
+ return placeholderCount > 0 && (args.length - (formatIndex + 1)) >= placeholderCount;
+ }
+
function getConsoleFormatIndex(args) {
- if (hasConsoleFormatSubstitution(args[0])) return 0;
- return isEnhancedLogPrefix(args[0]) && hasConsoleFormatSubstitution(args[1]) ? 1 : -1;
+ if (hasResolvableConsoleFormatSubstitution(args, 0)) return 0;
+ return isEnhancedLogPrefix(args[0]) && hasResolvableConsoleFormatSubstitution(args, 1) ? 1 : -1;
}Also applies to: 334-336
🤖 Prompt for AI Agents
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.
In `@packages/devtools-vite/src/virtual-console.ts` around lines 321 - 324, The
preserve-format detection in getConsoleFormatIndex is too permissive and can
treat literal percent text like “100%c” as a format string when there are no
matching substitution arguments. Update the logic around getConsoleFormatIndex
and the related preserve-format path to only preserve formatting when the number
of actual console placeholders is supported by the available trailing args, so
literal % sequences are not reclassified after prefix injection.
1 participant
🎯 Changes
Server log messages that use console format strings (
%s,%d,%c, etc.) are now substituted correctly when forwarded to the browser devtools console, including the default enhanced-logs path where the source-location prefix sits before the user's arguments. Previously the format string was passed through as a plain argument, so substitutions were not applied and the raw%stokens appeared in the panel.The SSE bridge that forwards server-side
console.log/console.errordid not detect format strings in all cases: with enhanced logs enabled (the default),enhanceConsoleLogprepends aLOG /path:line:colprefix, so the real format string was no longer the first argument and the substitution path was skipped. This now accounts for the enhanced-log prefix, the direct SSE path, and the%c/empty-argument edge cases. Closes #435.✅ Checklist
pnpm test:pr.🚀 Release Impact
Summary by CodeRabbit
New Features
%sand%csubstitutions.Bug Fixes