File path case mismatch

What this failure means

A file or module import path uses a different capitalisation from the actual filename on disk. On case-sensitive filesystems (Linux CI runners), this causes an immediate build failure.

Symptoms

Faultline looks for one or more of these log fragments:

cannot find module
module not found
file not found:
case-insensitive
path is not a file
capitalization
wrong case

Diagnosis

A file or module import path uses a different capitalisation from the actual filename on disk. On case-sensitive filesystems (Linux CI runners), this causes an immediate build failure.

Fix steps

1. Identify the mismatched import: compare the exact filename on disk with the casing used in the import statement.

2. Find all case variants of the file regardless of the current OS:

   find . -iname "filename.ts" -not -path "*/node_modules/*"
   git ls-files | grep -i <filename>
   

3. Rename the file or fix the import so the casing is consistent across the codebase — make the fix on a case-sensitive file system (Linux CI) where the mismatch is visible, not macOS where it is silently accepted.

4. Search the entire codebase for all occurrences before committing:

   grep -rn "from.*[Ff]ilename" src/
   

5. For TypeScript projects, enable "forceConsistentCasingInFileNames": true in tsconfig.json to catch future mismatches at compile time rather than only on case-sensitive file systems.

Validation

• find . -iname "<filename>" -not -path "*/node_modules/*" returns exactly one result with the intended casing.
• Re-run the build and confirm no case-sensitivity error.

Why it matters

macOS and Windows use case-insensitive filesystems by default. Code written on those platforms may use inconsistent capitalisation that goes undetected locally but breaks when the CI runner uses a case-sensitive Linux filesystem.

Prevention

• Enforce consistent file naming conventions with a linter.
• Run git config core.ignorecase false to make Git’s case-sensitive logic consistent with Linux.
• Add a CI check for case collisions: git ls-files | sort -f | uniq -Di.
• Prefer one filename casing convention per language or package so imports are easy to review mechanically.

Try it locally

git ls-files | sort -f | uniq -Di
git ls-files | sort -f | uniq -Di

How Faultline detects it

Use faultline explain path-case-mismatch to see the full playbook.

faultline analyze build.log
faultline explain path-case-mismatch

Generated from playbooks/bundled/log/build/path-case-mismatch.yaml. Do not edit directly.