[refurb] Implement write-whole-file (FURB103)

crates/ruff_linter/resources/test/fixtures/refurb/FURB103.py

@@ -0,0 +1,132 @@
+def foo():
+    ...
+
+
+def bar(x):
+    ...
+
+
+# Errors.
+
+# FURB103
+with open("file.txt", "w") as f:
+    f.write("test")
+
+# FURB103
+with open("file.txt", "wb") as f:
+    f.write(foobar)
+
+# FURB103
+with open("file.txt", mode="wb") as f:
+    f.write(b"abc")
+
+# FURB103
+with open("file.txt", "w", encoding="utf8") as f:
+    f.write(foobar)
+
+# FURB103
+with open("file.txt", "w", errors="ignore") as f:
+    f.write(foobar)
+
+# FURB103
+with open("file.txt", mode="w") as f:
+    f.write(foobar)
+
+# FURB103
+with open(foo(), "wb") as f:
+    # The body of `with` is non-trivial, but the recommendation holds.
+    bar("pre")
+    f.write(bar())
+    bar("post")
+    print("Done")
+
+# FURB103
+with open("a.txt", "w") as a, open("b.txt", "wb") as b:
+    a.write(x)
+    b.write(y)
+
+# FURB103
+with foo() as a, open("file.txt", "w") as b, foo() as c:
+    # We have other things in here, multiple with items, but the user
+    # writes a single time to file and that bit they can replace.
+    bar(a)
+    b.write(bar(bar(a + x)))
+    bar(c)
+
+
+# FURB103
+with open("file.txt", "w", newline="\r\n") as f:
+    f.write(foobar)
+
+
+# Non-errors.
+
+with open("file.txt", errors="ignore", mode="wb") as f:
+    # Path.write_bytes() does not support errors
+    f.write(foobar)
+
+f2 = open("file2.txt", "w")
+with open("file.txt", "w") as f:
+    f2.write(x)
+
+# mode is dynamic
+with open("file.txt", foo()) as f:
+    f.write(x)
+
+# keyword mode is incorrect
+with open("file.txt", mode="a+") as f:
+    f.write(x)
+
+# enables line buffering, not supported in write_text()
+with open("file.txt", buffering=1) as f:
+    f.write(x)
+
+# dont mistake "newline" for "mode"
+with open("file.txt", newline="wb") as f:
+    f.write(x)
+
+# I guess we can possibly also report this case, but the question
+# is why the user would put "w+" here in the first place.
+with open("file.txt", "w+") as f:
+    f.write(x)
+
+# Even though we write the whole file, we do other things.
+with open("file.txt", "w") as f:
+    f.write(x)
+    f.seek(0)
+    x += f.read(100)
+
+# This shouldn't error, since it could contain unsupported arguments, like `buffering`.
+with open(*filename, mode="w") as f:
+    f.write(x)
+
+# This shouldn't error, since it could contain unsupported arguments, like `buffering`.
+with open(**kwargs) as f:
+    f.write(x)
+
+# This shouldn't error, since it could contain unsupported arguments, like `buffering`.
+with open("file.txt", **kwargs) as f:
+    f.write(x)
+
+# This shouldn't error, since it could contain unsupported arguments, like `buffering`.
+with open("file.txt", mode="w", **kwargs) as f:
+    f.write(x)
+
+# This could error (but doesn't), since it can't contain unsupported arguments, like
+# `buffering`.
+with open(*filename, mode="w") as f:
+    f.write(x)
+
+# This could error (but doesn't), since it can't contain unsupported arguments, like
+# `buffering`.
+with open(*filename, file="file.txt", mode="w") as f:
+    f.write(x)
+
+# Loops imply multiple writes
+with open("file.txt", "w") as f:
+    while x < 0:
+        f.write(foobar)
+
+with open("file.txt", "w") as f:
+    for line in text:
+        f.write(line)

crates/ruff_linter/src/checkers/ast/analyze/statement.rs

@@ -1217,6 +1217,9 @@ pub(crate) fn statement(stmt: &Stmt, checker: &mut Checker) {
             if checker.enabled(Rule::ReadWholeFile) {
                 refurb::rules::read_whole_file(checker, with_stmt);
             }
+            if checker.enabled(Rule::WriteWholeFile) {
+                refurb::rules::write_whole_file(checker, with_stmt);
+            }
             if checker.enabled(Rule::UselessWithLock) {
                 pylint::rules::useless_with_lock(checker, with_stmt);
             }

crates/ruff_linter/src/codes.rs

@@ -1035,6 +1035,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
 
         // refurb
         (Refurb, "101") => (RuleGroup::Preview, rules::refurb::rules::ReadWholeFile),
+        (Refurb, "103") => (RuleGroup::Preview, rules::refurb::rules::WriteWholeFile),
         (Refurb, "105") => (RuleGroup::Preview, rules::refurb::rules::PrintEmptyString),
         #[allow(deprecated)]
         (Refurb, "113") => (RuleGroup::Nursery, rules::refurb::rules::RepeatedAppend),

crates/ruff_linter/src/rules/refurb/mod.rs

@@ -40,6 +40,7 @@ mod tests {
     #[test_case(Rule::MetaClassABCMeta, Path::new("FURB180.py"))]
     #[test_case(Rule::HashlibDigestHex, Path::new("FURB181.py"))]
     #[test_case(Rule::ListReverseCopy, Path::new("FURB187.py"))]
+    #[test_case(Rule::WriteWholeFile, Path::new("FURB103.py"))]
     fn rules(rule_code: Rule, path: &Path) -> Result<()> {
         let snapshot = format!("{}_{}", rule_code.noqa_code(), path.to_string_lossy());
         let diagnostics = test_path(

crates/ruff_linter/src/rules/refurb/rules/mod.rs

@@ -24,6 +24,7 @@ pub(crate) use type_none_comparison::*;
 pub(crate) use unnecessary_enumerate::*;
 pub(crate) use unnecessary_from_float::*;
 pub(crate) use verbose_decimal_constructor::*;
+pub(crate) use write_whole_file::*;
 
 mod bit_count;
 mod check_and_remove_from_set;
@@ -51,3 +52,4 @@ mod type_none_comparison;
 mod unnecessary_enumerate;
 mod unnecessary_from_float;
 mod verbose_decimal_constructor;
+mod write_whole_file;