fix(httpx): honor -pr http11 in h2 probe client

[wh0amibjm]

Follow-up to #2414 and issue #2240.

This patch ensures explicit -pr http11 is honored across both retry fallback and HTTP/2 probe paths:

• sets httpx.client2 = httpx.client.HTTPClient in HTTP11 mode
• keeps dedicated HTTP/2 client only when protocol is not forced to HTTP11
• adds/updates tests for both behaviors
• adds dialer cleanup via t.Cleanup in protocol tests

Validation:

go test ./common/httpx -run TestNew_ -count=1

/claim #2240

Summary by CodeRabbit

• New Features

  • New HTTP/1.1 mode that disables HTTP/2 fallback and uses a single shared client for HTTP/1.1 requests.
  • Protocol selection now determines whether a dedicated HTTP/2 transport is created.

• Tests

  • Added unit tests validating behavior for HTTP/1.1 (shared client) and non-HTTP/1.1 (dedicated HTTP/2 transport).

[neo-by-projectdiscovery-dev]

Neo - PR Security Review

No security issues found

Highlights

• Test assertions at lines 30-33 properly validate that both client.HTTPClient2 and client2 reference the same HTTP/1.1 transport when protocol is forced
• The incremental diff contains only test improvements and no changes to production security-sensitive code paths

Hardening Notes

• Test assertions at lines 30-33 properly validate that both client.HTTPClient2 and client2 reference the same HTTP/1.1 transport when protocol is forced
• The incremental diff contains only test improvements and no changes to production security-sensitive code paths

_{Comment @neo help for available commands. · Open in Neo}

[coderabbitai]

Walkthrough

Replaces a string literal protocol check with a constant and conditionally reuses the primary HTTP client for HTTP/1.1 (disabling HTTP/2 transport creation); preserves previous HTTP/2 transport initialization for non-HTTP/1.1. Two tests validate both behaviors.

Changes

Cohort / File(s)	Summary
Core HTTP client behavior common/httpx/httpx.go	Switches protocol check from literal "http11" to HTTP11 constant; when HTTP11 is selected, assigns HTTPClient2 and client2 to the primary HTTPClient (skipping separate http2.Transport creation); retains existing SNI, proxy, and TLS handling in other branches.
Protocol tests common/httpx/httpx_protocol_test.go	Adds two tests: one asserting HTTP/1.1 mode reuses the same client and no http2.Transport is created; another asserting non-HTTP/1.1 mode creates a distinct http2.Transport and separate client.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Poem

🐰 I tunneled through options, found a neat switch,
HTTP/1.1 snugly reuses the same stitch,
HTTP/2 keeps its bouncy new gear,
Tests hop along to make it clear,
A tiny change, a confident twitch.

🚥 Pre-merge checks | ✅ 2 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 33.33% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'fix(httpx): honor -pr http11 in h2 probe client' accurately and specifically describes the main change—ensuring the HTTP/1.1 protocol flag is respected in the HTTP/2 probe client path, which aligns with the core modifications across both httpx.go and the test files.

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✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
• 📝 Generate docstrings (commit on current branch)

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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[coderabbitai]

Actionable comments posted: 1

🧹 Nitpick comments (1)

common/httpx/httpx.go (1)

186-206: Use the HTTP11 typed constant instead of the "http11" string literal

The test file uses opts.Protocol = HTTP11 (the typed Proto constant defined in proto.go), but the production code at lines 156 and 188 compares against the bare string "http11". Using the constant in both places keeps the comparison DRY and eliminates a silent mismatch risk if the constant value ever changes.

♻️ Proposed change (applies to lines 156 and 188)

-	if httpx.Options.Protocol == "http11" {
+	if httpx.Options.Protocol == HTTP11 {
 		// ... protocol handling
 	}

🤖 Prompt for AI Agents

Verify each finding against the current code and only fix it if needed.

In `@common/httpx/httpx.go` around lines 186 - 206, Replace the string literal
"http11" comparisons with the typed constant HTTP11 (the Proto constant defined
in proto.go) so the checks use httpx.Options.Protocol == HTTP11 instead of ==
"http11"; update both locations where the literal is used (the branch deciding
HTTP/1.1 mode and the related branch later in the file) to reference the HTTP11
constant to keep comparisons consistent and DRY.

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@common/httpx/httpx_protocol_test.go`:
- Around line 11-24: The test leaks a process-wide GODEBUG change because
New(&opts) with opts.Protocol = HTTP11 calls os.Setenv("GODEBUG",
"http2client=0") and never restores it; modify
TestNew_HTTP11DisablesRetryableHTTP2Fallback to capture the original
os.Getenv("GODEBUG") before calling New, and register a t.Cleanup that restores
the original value (use os.Setenv to restore non-empty original, or os.Unsetenv
if it was empty) so the GODEBUG setting is returned to its prior state after the
test; reference the New function, opts.Protocol/HTTP11 setup, and the
os.Setenv("GODEBUG", ...) side effect when applying the fix.

---

Nitpick comments:
In `@common/httpx/httpx.go`:
- Around line 186-206: Replace the string literal "http11" comparisons with the
typed constant HTTP11 (the Proto constant defined in proto.go) so the checks use
httpx.Options.Protocol == HTTP11 instead of == "http11"; update both locations
where the literal is used (the branch deciding HTTP/1.1 mode and the related
branch later in the file) to reference the HTTP11 constant to keep comparisons
consistent and DRY.

[wh0amibjm]

Addressed CodeRabbit follow-up in 58e14d4:

• replaced string literals with typed constant HTTP11 in protocol checks
• added GODEBUG restore cleanup in TestNew_HTTP11DisablesRetryableHTTP2Fallback

Validation:

go test ./common/httpx -run TestNew_ -count=1

[coderabbitai]

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Duplicate comments:
In `@common/httpx/httpx_protocol_test.go`:
- Around line 16-23: The code correctly uses os.LookupEnv to capture
originalGODEBUG and hadGODEBUG and restores state in t.Cleanup using os.Setenv
or os.Unsetenv; keep this implementation as-is (no change needed) and ensure the
variables originalGODEBUG, hadGODEBUG and the t.Cleanup block remain present so
an originally unset GODEBUG is restored to unset rather than set to an empty
string.

[wh0amibjm]

Quick follow-up after latest bot review pass:

• re-checked current branch (58e14d4) against prior actionable feedback
• no remaining actionable review items detected on my side
• tests for touched area still pass locally:
  • go test ./common/httpx -run TestNew_ -count=1

Ready for maintainer review/merge when convenient.