hyb generate tries to read a sibling directory ending in .go #4418

Activity

1. dukenordj-rgb commented on Nov 13, 2026

   

   dukenordj-rgb

   on Nov 13, 2026

   Contributor

   More actions

   Root Cause Analysis

   The bug stems from directory traversal logic in the code generator that uses a naive suffix check (e.g., checking if a directory name ends with .go) rather than strictly inspecting file extensions or leveraging Go's standard package discovery semantics via go/packages or os.Stat checks combined with regular file filters.

   When hyb generate scans the package directory, it encounters the subdirectory named nested.go. Because the string ends in .go, the generator misinterprets the directory as a target source file, attempts to open and read it as a regular file (os.Open or equivalent), and subsequently fails with an EISDIR (on Unix-like systems) or access/read error (on Windows, where opening a directory handle for sequential file reading fails differently). Go's own toolchain correctly ignores subdirectories during package loading, even if they possess a .go extension, because source files must be regular files.

   Patch Snippet

   To fix the issue, the file discovery pass must ensure that candidate paths point to regular files and not directories, while explicitly ignoring or filtering out any directory entries regardless of their naming scheme.

   // Before: naive suffix check or unfiltered directory iteration
   if strings.HasSuffix(entry.Name(), ".go") {
       // attempts to read entry as a source file
   }
   
   // After: enforce regular file check via os.FileInfo / fs.DirEntry
   if entry.IsDir() {
       continue
   }
   
   if !strings.HasSuffix(entry.Name(), ".go") {
       continue
   }

   Ensure the traversal implementation uses fs.DirEntry.Type().IsRegular() or runs an os.Stat on the candidate path to reject directories masquerading with file-like extensions.

   Regression Test Coverage

   1. Subdirectory with .go Suffix Test:
      Create a test case workspace featuring a package directory containing a subdirectory explicitly named foo.go. Run the code generator against a valid .hy file in the root of the package. Verify that the generator completes with exit code 0 and successfully ignores the foo.go subdirectory without throwing an I/O error.

   2. Cross-Platform File System Sanity Test:
      Validate that path resolution handles trailing extension collisions across Unix and Windows directory streams, ensuring that IsDir() guards protect file-reading routines uniformly.