feat: add Bash/Shell (.sh) parsing support (#197)

[azizur100389]

Summary

Register .sh / .bash / .zsh / .ksh with tree-sitter-bash. Extract File and Function nodes for shell function definitions, CALLS edges for command invocations (local functions and external binaries), and IMPORTS_FROM edges for source / . dot-includes. test_* prefix is classified as Test kind.

Closes #197.

Root cause

Shell-script-heavy repos (installers, infra, CI tooling) previously indexed to 0 nodes / 0 edges because .sh was not in EXTENSION_TO_LANGUAGE. build_or_update_graph reported parsed 0 files for FragHub-style repos, which blocked architecture mapping and flow detection for the category of projects that most need them.

What's supported

• Function definitions in both tree-sitter-bash shapes

  foo() { ... }
  function foo { ... }
  function foo() { ... }

• Call extraction — tree-sitter-bash wraps every invocation in a command node with a command_name > word child. Local calls resolve to qualified names (file.sh::greet); external binaries (curl, grep, awk) are recorded with their raw name, consistent with how unresolved calls work in other languages.
• Dot-includes as imports — source lib.sh and . lib.sh emit IMPORTS_FROM edges. Both bareword (source lib/utils.sh) and quoted-string (source "lib/helpers.sh") arguments are handled.
• Test detection — test_* prefix classified as Test kind via the existing _TEST_PATTERNS list.

Implementation

1. EXTENSION_TO_LANGUAGE — added .sh, .bash, .zsh, .ksh → "bash"
2. _CLASS_TYPES["bash"] = [] (no class concept in bash)
3. _FUNCTION_TYPES["bash"] = ["function_definition"]
4. _IMPORT_TYPES["bash"] = [] (source handled via constructs handler)
5. _CALL_TYPES["bash"] = ["command"]
6. New _extract_bash_constructs() + _bash_get_source_target() helpers following the _extract_lua_constructs pattern, dispatched next to the existing Lua/Luau handler.
7. _get_name — new "bash" branch that reads the first word child of a function_definition (handles both paren and function-keyword forms).
8. _get_call_name — new "bash" branch that reads command_name > word, skipping commands whose name is a variable expansion (can't be resolved statically).

Scope caveats

• No cross-file call resolution beyond direct source includes (bash has no formal module system).
• Calls whose name is a variable expansion ($foo, $(cmd)) are not statically resolvable and are skipped by _get_call_name.
• Pipelines, subshells, heredocs are parsed by tree-sitter but not semantically linked yet.

Tests added (tests/test_multilang.py::TestBashParsing — 10 tests)

• test_detects_language (.sh, .bash, .zsh)
• test_finds_function_definitions_paren_form
• test_finds_function_definitions_function_keyword_form
• test_finds_source_imports (source + . + quoted string)
• test_finds_calls_between_local_functions
• test_finds_external_command_calls
• test_finds_contains_edges
• test_detects_test_functions
• test_nodes_have_bash_language
• test_calls_inside_functions

New fixture: tests/fixtures/sample.sh exercises both function-definition forms, both import forms, local + external call mix, and test_* naming.

Test results

Stage	Result
Stage 1 — new targeted tests	10/10 passed
Stage 2 — tests/test_multilang.py full	140/140 passed — zero regressions across any language
Stage 3 — adjacent tests/test_parser.py	67/67 passed
Stage 4 — full suite	705 passed (up from 699 baseline — +6 new), 6 pre-existing Windows failures in test_incremental / test_notebook (verified identical on unchanged main)
Stage 5 — ruff check on changed files	clean
Stage 6 — fixture smoke parse	8 nodes, 26 edges — all expected function, call, import, and test nodes present

Zero regressions. All new code is gated on the bash language check so existing languages are untouched.

[tirth8205]

Thank you for this @CodeBlackwell — closing as superseded by PR #227 which already shipped Bash/Shell support in v2.3.0 (now on PyPI, along with v2.3.1 that adds the Windows MCP hang fix).

Your PR was in flight at the same time I shipped #227, so this isn't redundant work on your end — the two implementations arrived essentially in parallel. Both approaches are very similar: .sh/.bash/.zsh registered with tree-sitter-bash, function_definition → Function nodes, command → CALLS edges, source/. → IMPORTS_FROM. The shipped version uses _extract_bash_source_command for the import hook and has 7 multilang tests covering the same cases you tested.

If there's anything your implementation does that mine doesn't (e.g. .ksh extension, additional test coverage), please open a follow-up issue pointing at the specific feature and I'll merge it in. The .ksh extension in particular looks worth adding — I didn't include it in #227.

Really appreciate the thorough test breakdown (10/10 targeted, 140/140 multilang, 705 full suite). That's exactly how I'd want a PR tested.