Getting Started with IndigoPerl: Installation & First Script

Debugging IndigoPerl: Common Errors and FixesIndigoPerl is a Perl distribution tailored for certain workflows (packaged modules, platform-specific builds, or curated module sets). Debugging issues that arise when installing, running, or developing with IndigoPerl follows many of the same principles as debugging any Perl environment, but there are some recurring, distribution-specific issues worth knowing. This article covers common errors, practical diagnostic steps, and concrete fixes so you can get back to productive development quickly.

---

Table of contents

1. Environment and path problems
2. Installation and dependency failures
3. Module version conflicts
4. XS (compiled extension) build issues
5. Runtime errors and warnings
6. File encoding and locale problems
7. Permission and sandboxing issues
8. Debugging tools and best practices
9. Appendix: quick checklist

---

1. Environment and path problems

Symptoms

• Scripts run with the system Perl instead of IndigoPerl.
• Modules installed under one Perl are not visible to another.
• @INC doesn’t include IndigoPerl library paths.

Diagnosis

• Check which Perl is being executed:
  • Run which perl (on Unix-like systems) or where perl (Windows).
  • Run perl -V to inspect @INC and compile-time configuration.
• Inspect environment variables:
  • PATH order determines which perl is found first.
  • PERL5LIB and PERL5OPT can override module search paths and behavior.

Fixes

• Ensure IndigoPerl’s bin directory appears first in PATH. Example (Unix):

  
  export PATH=/opt/indigoperl/bin:$PATH 

• On Windows, adjust the PATH order in System Properties or use the IndigoPerl-provided shortcut/startup script that sets environment variables for you.
• Use the IndigoPerl perl explicitly in scripts by shebang:

  
  #!/usr/bin/env /opt/indigoperl/bin/perl 

  or directly:

  
  #!/opt/indigoperl/bin/perl 

• For temporary runs, invoke modules with:

  
  /opt/indigoperl/bin/perl -I/path/to/additional/lib script.pl 

---

2. Installation and dependency failures

Symptoms

• cpan or cpanm failing to install modules.
• Builds stop on missing prerequisites or failing tests.

Diagnosis

• Look at the error output carefully — it often names the missing dependency or failing test.
• Run installs with verbose logging:

  
  cpanm --verbose Some::Module 

• Check network access for fetching modules and any corporate proxy settings.

Fixes

• Install missing prerequisites explicitly, using the IndigoPerl package manager if one exists, or cpan/cpanm tied to IndigoPerl:

  
  /opt/indigoperl/bin/cpanm --installdeps . 

• If tests fail due to missing system libraries (common for XS modules), install the corresponding OS packages (e.g., libssl-dev, zlib-dev).
• For environments with restricted network access, use mirror or local CPAN repositories; set PERL_CPANM_OPT or configure cpan client to use mirrors.

---

3. Module version conflicts

Symptoms

• “Subroutine not found” or “Can’t locate object method” errors after upgrading/downgrading modules.
• Unexpected behavior due to multiple versions of same module in @INC.

Diagnosis

• Print @INC at runtime:

  
  use Data::Dumper; print Dumper @INC; 

• Use Module::CoreList or Devel::Trace to inspect loaded module versions:

  
  perl -MModule::Loaded -E 'say for sort keys %INC' 

• Search for duplicates in standard and local library paths.

Fixes

• Remove or rename older module files from directories not intended for active use.
• Use local::lib or perlbrew/perl-switch tools to isolate environments.
• Pin versions in your application’s cpanfile or Makefile.PL and use cpanm –installdeps to reproduce consistent setups.
• Force reinstall a module to the desired version:

  
  cpanm Module::[email protected] 

---

4. XS (compiled extension) build issues

Symptoms

• Compilation failures, linker errors, or missing .so/.dll after installation.
• Tests failing with messages about undefined symbols.

Diagnosis

• Capture the actual compiler/linker error (gcc, clang, or MSVC output).
• Ensure you have a compatible C compiler and matching architecture (32-bit vs 64-bit).
• Check for missing C libraries or headers named in error messages.

Fixes

• Install required system development packages (for example, on Debian/Ubuntu: build-essential, libssl-dev, perl-dev).
• Match compiler architecture to IndigoPerl build (install 64-bit compilers for 64-bit Perl).
• On Windows, use the recommended compiler/version for your IndigoPerl build (Strawberry Perl or MSVC toolchain equivalents); sometimes installing Strawberry Perl tools or using the IndigoPerl-supplied build toolchain helps.
• Rebuild with verbose make:

  
  perl Makefile.PL make make test make install 

  and examine output for missing include paths; add INC and LIBS flags if needed:

  
  perl Makefile.PL INC='-I/path/to/include' LIBS='-L/path/to/lib -lmylib' 

---

5. Runtime errors and warnings

Symptoms

• Classic Perl errors: syntax errors, “Undefined subroutine”, “Can’t locate file for module”, warnings from strict/warnings.
• Deprecation or feature-related errors (e.g., use of experimental features).

Diagnosis

• Re-run scripts with warnings and strict enabled:

  
  perl -Mstrict -Mwarnings script.pl 

• Use Carp::Always or Devel::Confess to get stack traces for fatal errors.
• Check for typos, incorrect package names, or wrong capitalization (Perl is case-sensitive).

Fixes

• Fix obvious syntax/typo issues flagged by the interpreter.
• Enable autodie or check return values for I/O operations to get clearer failure points.
• Use feature pragmas appropriately or upgrade/downgrade Perl if a module requires specific Perl features.

---

6. File encoding and locale problems

Symptoms

• Garbage characters or mojibake when printing non-ASCII text.
• IO operations failing or behaving differently across platforms.

Diagnosis

• Check current locale:

  
  locale 

• Inspect file encoding and any use of binmode on filehandles.
• Check whether source files have correct UTF-8 BOM/encoding.

Fixes

• Explicitly set IO layers:

  
  binmode(STDOUT, ':encoding(UTF-8)'); 

• Use the proper pragma for source encoding:

  
  use utf8; use open ':std', ':encoding(UTF-8)'; 

• Configure environment locales to a UTF-8 variant when working with Unicode data.

---

7. Permission and sandboxing issues

Symptoms

• “Permission denied” when installing modules or writing files.
• CI or containerized environments can’t access necessary resources.

Diagnosis

• Verify file ownership and permissions.
• Check whether IndigoPerl or your process runs with restricted privileges or inside a container with limited mounts.

Fixes

• Use sudo or install modules to a local::lib location if you don’t have root access:

  
  cpanm --local-lib=~/perl5 Module::Name eval $(perl -I ~/perl5/lib/perl5 -Mlocal::lib) 

• On CI, adjust permissions or bind mounts so the build tools can write to expected paths.
• For production sandboxes, move writable directories to a dedicated data path and ensure correct permissions.

---

8. Debugging tools and best practices

Essential tools

• perl -V (configuration and @INC)
• perl -c (compile-only syntax check)
• Devel::Confess / Carp::Always (stack traces)
• Devel::Peek (inspect internals)
• Devel::Trace (trace execution)
• Devel::NYTProf (profiler for performance bottlenecks)
• Test::More and prove for automated tests

Best practices

• Reproduce issues with minimal scripts to isolate causes.
• Use version control and pin dependencies (cpanfile + cpanm).
• Maintain a local development environment (local::lib, perlbrew, or containers) matching production IndigoPerl.
• Log runtime errors with context (using Log::Any or Log::Log4perl).
• Run test suites after module installs; investigate test failures instead of skipping them.

---

9. Appendix: quick checklist

• Which perl is running? Run which perl / perl -V.
• Is PATH correct? Ensure IndigoPerl bin appears before system perl.
• Are dev tools installed? Have compiler and headers for XS builds.
• Do you have network/access to CPAN? Configure proxies or mirrors.
• Are module versions conflicting? Inspect %INC and @INC.
• Are permissions correct? Use local::lib or adjust ownership.
• Is encoding handled? Use utf8 pragma and binmode for IO.
• Are you using debugging tools? Enable Carp::Always, NYTProf, Devel::* as needed.

---

If you paste a failing error message or the output of perl -V and perl -V:perlpath (or which perl) I can give targeted steps to resolve that specific IndigoPerl issue.