[IOS-XR] Fix show vrf all detail parser - capture all interface names

[Kani999]

Description

Enhance interface parsing in 'show vrf all detail' parser

Implemented a general regex pattern to capture all interface names:

• Replaced the previous regex that relied on specific interface prefixes (e.g., Gi, Bun, Ten, etc.) with a more general pattern r'^(?P<intf>[A-Za-z][-A-Za-z0-9/.:]+)$'.
  • This allows the parser to match any interface name, accommodating various naming conventions and ensuring that all interfaces are properly captured.
• Introduced in_interfaces_section flag for accurate section tracking:
  • Initialized in_interfaces_section = False at the beginning of the parsing process.
  • Set in_interfaces_section = True upon encountering the Interfaces: line.
  • Used this flag to determine when interface lines should be parsed.
  • When a non-interface line is encountered within the Interfaces section, set in_interfaces_section = False
  • This ensures that the parser continues to process the current line with other parsing rules, preventing the omission of critical sections like address families and route targets.

Motivation and Context

Replaced the previous regex that relied on specific interface prefixes (e.g., Gi, Bun, Ten, etc.) with a more general pattern

Checklist:

• I have updated the changelog.
• I have updated the documentation (If applicable).
• I have added tests to cover my changes (If applicable).
• All new and existing tests passed.
• All new code passed compilation.

Closes #910

[Kani999]

Hi there! 👋
If anyone revisits this PR in the future:
Thank you for taking the time to look at this contribution. If you have any questions about the changes, need further clarification, or would like additional context, please feel free to tag me @Kani999. I appreciate your review and feedback!

Best regards,
Kani999

[Kani999]

Hi team,

This PR (#911) has been open since recently, but I'm still waiting for accept or deny decision. Any update on review?

I'd appreciate your feedback!

Thanks

[Kani999]

Verified: current genie/main still fails — this PR is needed

Tested against genie/main at commit 285024fb050cdbe54ee5c8490df5068661a41061 (release v26.2).

What was tested

A comprehensive golden output test (golden_output_5) with 31 interface names covering various IOS-XR naming conventions was run against the unmodified main branch parser using an isolated venv.

Results

• Existing tests (golden_output_1–4): all PASS on main ✅
• New test (golden_output_5): FAILS on main ❌ — 11 out of 31 interface names are silently dropped

The v26.2 release expanded the regex to include more prefixes (HundredGigE, FortyGigE, FiftyGigE, etc.), but the allowlist approach still misses:

Still missing	Description
Te0/0/0/0.3	TenGigE short form
Fo0/0/0/0.3	FortyGigE short form
Hu0/0/0/0.3	HundredGigE short form
BE2	Bundle-Ether short form
Nu1	Null short form
Null0	Null interface
FortyGigabitEthernet0/0/0/0.2	FortyGigabitEthernet long form
HundredGigabitEthernet0/0/0/0.2	HundredGigabitEthernet long form
ManagementEthernet1/RP0/CPU0/0	ManagementEthernet long form
POS0/0/0/0	Packet over SONET
PacketOverSonet0/0/0/1	PacketOverSonet long form

Why the allowlist approach keeps breaking

Every time Cisco adds a new interface type or users encounter a different abbreviation, the regex needs to be manually extended. This PR replaces it with a generic pattern ([A-Za-z][-A-Za-z0-9/.:]+) guarded by the in_interfaces_section state flag, which is future-proof.

PR checklist status

• ✅ make json — no changes needed (parser registration unchanged)
• ✅ Changelog entry at genieparser/changelog/undistributed/changelog_show_vrf_all_detail_iosxr_20241108103720.rst
• ✅ All 6 tests pass on this branch (golden_output_1–5 + empty)
• ✅ Existing tests still pass (no regressions)