Upstream gookit/goutil state of the touched files before 71dcf88743

PR.md

@@ -1,73 +0,0 @@
-# fix(strutil): center-aligned Resize/Align overflows the requested length
-
-## Problem
-
-`strutil.Resize` / `strutil.Align` (and their utf8 variants) with
-`comdef.Center` alignment produce strings longer than the requested length for
-almost every non-empty input:
-
-```go
-strutil.Resize("ab", 6, comdef.Center)   // "  ab   " (len 7), want "  ab  " (len 6)
-strutil.Resize("ab", 4, comdef.Center)   // " ab  "   (len 5), want " ab "   (len 4)
-strutil.Resize("abc", 7, comdef.Center)  // "  abc   "(len 8), want "  abc  "(len 7)
-```
-
-The extra space that centers an odd amount of padding is added unconditionally
-whenever the input is non-empty, not only when the padding is actually odd.
-
-## Root cause
-
-`strutil/padding.go`, `resize`:
-
-```go
-if align == comdef.Center {
-    padLn := (wantLen - sLen) / 2
-    if diff = wantLen - padLn*2; diff > 0 {  // wrong: missing "- sLen"
-        s += " "
-    }
-    ...
-}
-```
-
-The condition is meant to detect an odd amount of total padding
-(`wantLen - sLen`). Simplifying the buggy expression:
-
-```
-wantLen - 2*padLn = wantLen - 2*floor((wantLen-sLen)/2)
-                  = sLen + ((wantLen - sLen) mod 2)
-```
-
-so `diff > 0` is true whenever `sLen > 0`, regardless of the padding parity.
-The result is one space too long for every non-empty string with even padding.
-
-The existing `TestResize("title", 20, PosMiddle)` case did not catch this
-because its padding (15) is odd, where the extra space is legitimately needed.
-
-## Fix
-
-Compare against the actual leftover padding by subtracting `sLen`:
-
-```go
-if diff = wantLen - sLen - padLn*2; diff > 0 {
-    s += " "
-}
-```
-
-This adds the extra space only when `(wantLen - sLen)` is odd, keeping the odd
-case (e.g. the "title" test) unchanged.
-
-## Test
-
-Added `TestResize_center_length` in `strutil/padding_test.go` asserting both the
-exact result and `len(result) == wantLen` for even- and odd-padding cases.
-
-- Gate: `go test ./strutil/ -run TestResize` -> ok (PASS)
-- `go vet ./strutil/` -> exit 0
-- `go build ./...` -> exit 0
-
-Counterfactual: reverting the change makes the new test fail with
-`actual: int(7)` / `actual: "  ab   "` vs the expected length 6 / `"  ab  "`.
-
-Note: `TestDateSNv3/dateLen4_base62` in `strutil/gensn_test.go` is flaky and
-already fails on the unmodified base commit (it asserts uniqueness of randomly
-generated serial numbers); it is unrelated to this change.

strutil/split.go

@@ -166,12 +166,6 @@ func Substr(s string, pos, length int) string {
 		stopIdx = strLn + length
 	}
 
-	// A negative length can move stopIdx before pos; clamp to avoid an
-	// out-of-range slice.
-	if stopIdx < pos {
-		stopIdx = pos
-	}
-
 	return string(runes[pos:stopIdx])
 }
 

strutil/split_test.go

@@ -120,12 +120,6 @@ func TestSubstr(t *testing.T) {
 	assert.Eq(t, "", strutil.Substr("abcDEF", 23, 5))
 	assert.Eq(t, "cDEF12", strutil.Substr("abcDEF123", 2, -1))
 	assert.Eq(t, "cDEF", strutil.Substr("abcDEF123", 2, -3))
-
-	// negative length trimming more than the remaining substring must not
-	// panic; it should yield an empty string.
-	assert.Eq(t, "", strutil.Substr("hello", 4, -3))
-	assert.Eq(t, "", strutil.Substr("hello", 3, -5))
-	assert.Eq(t, "", strutil.Substr("abcDEF123", 8, -3))
 }
 
 func TestSplitInlineComment(t *testing.T) {