lib: also compare rmap source address when comparing nexthop source a…

[ak503]

…ddresses

Fix #19611

[greptile-apps]

Greptile Summary

This PR fixes issue #19611 by including the rmap_src field (a route-map-assigned source address) in nexthop comparison functions, preventing two nexthops that differ only in their rmap_src from being incorrectly treated as equal.

• Adds a new static helper _nexthop_rmap_source_cmp that wraps nexthop_g_addr_cmp for the rmap_src field, mirroring the existing _nexthop_source_cmp pattern.
• Calls _nexthop_rmap_source_cmp in _nexthop_cmp_no_labels (used by nexthop_cmp and nexthop_cmp_no_weight) before the existing _nexthop_source_cmp call.
• Inlines an equivalent nexthop_g_addr_cmp call for rmap_src in nexthop_cmp_basic, consistent with that function's existing style of inlining rather than using helpers.
• The change is hash-safe: rmap_src is already inside the _hash_begin/_hash_end region of struct nexthop and is already fed into jhash, so the hash/equality invariant is maintained.
• Minor cosmetic issue: the second parameter of _nexthop_rmap_source_cmp is indented with the same whitespace as in _nexthop_source_cmp, but since the new function name is longer the column alignment is off.

Confidence Score: 4/5

• Safe to merge — the fix is minimal, logically consistent with existing patterns, and hash-safe.
• The change correctly extends both comparison sites to include rmap_src, which is already hashed, so there is no hash/equality mismatch risk. The only issue found is a minor indentation misalignment in the new helper's function signature. Logic and data-flow are sound.
• No files require special attention beyond the minor indentation note in lib/nexthop.c.

Important Files Changed

Filename	Overview
lib/nexthop.c	Adds rmap_src comparison to both _nexthop_cmp_no_labels and nexthop_cmp_basic; logically correct since rmap_src is already in the hashed region of the struct. Minor indentation misalignment in the new helper function signature.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A["_nexthop_cmp_no_labels / nexthop_cmp_basic"] --> B{vrf_id equal?}
    B -- no --> Z[return diff]
    B -- yes --> C{type equal?}
    C -- no --> Z
    C -- yes --> D{weight/ifindex/gateway equal?}
    D -- no --> Z
    D -- yes --> E{srte_color equal?}
    E -- no --> Z
    E -- yes --> F["🆕 rmap_src compare\n(_nexthop_rmap_source_cmp)"]
    F -- not equal --> Z
    F -- equal --> G["src compare\n(_nexthop_source_cmp)"]
    G -- not equal --> Z
    G -- equal --> H[compare labels / backup indices]
    H --> I[return result]

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Prompt To Fix All With AI

This is a comment left during a code review.
Path: lib/nexthop.c
Line: 148-149

Comment:
**Parameter alignment is off in new function signature**

The second parameter of `_nexthop_rmap_source_cmp` is indented with the same whitespace as in `_nexthop_source_cmp`, but because the new function name is 5 characters longer, the second parameter no longer aligns with the opening parenthesis of the parameter list. With 8-space tabs, `const struct nexthop *nh1` begins at column 36, but `const struct nexthop *nh2` begins at column 31.

```suggestion
static int _nexthop_rmap_source_cmp(const struct nexthop *nh1,
				    const struct nexthop *nh2)
```

How can I resolve this? If you propose a fix, please make it concise.

_{Last reviewed commit: "lib: also compare rm..."}

[greptile-apps]

Parameter alignment is off in new function signature

The second parameter of _nexthop_rmap_source_cmp is indented with the same whitespace as in _nexthop_source_cmp, but because the new function name is 5 characters longer, the second parameter no longer aligns with the opening parenthesis of the parameter list. With 8-space tabs, const struct nexthop *nh1 begins at column 36, but const struct nexthop *nh2 begins at column 31.

Suggested change

	static int _nexthop_rmap_source_cmp(const struct nexthop *nh1,
	const struct nexthop *nh2)
	static int _nexthop_rmap_source_cmp(const struct nexthop *nh1,
	const struct nexthop *nh2)

Prompt To Fix With AI

This is a comment left during a code review.
Path: lib/nexthop.c
Line: 148-149

Comment:
**Parameter alignment is off in new function signature**

The second parameter of `_nexthop_rmap_source_cmp` is indented with the same whitespace as in `_nexthop_source_cmp`, but because the new function name is 5 characters longer, the second parameter no longer aligns with the opening parenthesis of the parameter list. With 8-space tabs, `const struct nexthop *nh1` begins at column 36, but `const struct nexthop *nh2` begins at column 31.

```suggestion
static int _nexthop_rmap_source_cmp(const struct nexthop *nh1,
				    const struct nexthop *nh2)
```

How can I resolve this? If you propose a fix, please make it concise.

_{Note: If this suggestion doesn't match your team's coding style, reply to this and let me know. I'll remember it for next time!}

[riw777]

looks good