Merge pull request github#21274 from github/tausbn/python-fix-parsing-of-format-specifiers

Python: Fix syntax error when `=` is used as a format fill character

Author: tausbn

python/extractor/semmle/util.py

@@ -10,7 +10,7 @@
 
 #Semantic version of extractor.
 #Update this if any changes are made
-VERSION = "7.1.7"
+VERSION = "7.1.8"
 
 PY_EXTENSIONS = ".py", ".pyw"
 

python/extractor/tests/parser/strings.py

@@ -86,3 +86,5 @@
 if 39:
     r'a\
     '
+if 40:
+    f"{x:=^20}"

python/extractor/tests/parser/template_strings_new.expected

@@ -1,4 +1,4 @@
-Module: [1, 0] - [18, 0]
+Module: [1, 0] - [20, 0]
   body: [
     Assign: [1, 0] - [1, 14]
       targets: [
@@ -191,4 +191,24 @@ Module: [1, 0] - [18, 0]
               ]
       ]
       orelse: None
+    If: [18, 0] - [18, 5]
+      test:
+        Num: [18, 3] - [18, 4]
+          n: 7
+          text: '7'
+      body: [
+        Expr: [19, 4] - [19, 43]
+          value:
+            TemplateString: [19, 4] - [19, 43]
+              prefix: 't"'
+              values: [
+                TemplateStringPart: [19, 6] - [19, 31]
+                  text: '"With a format specifier: "'
+                  s: 'With a format specifier: '
+                Name: [19, 32] - [19, 36]
+                  variable: Variable('name', None)
+                  ctx: Load
+              ]
+      ]
+      orelse: None
   ]

python/extractor/tests/parser/template_strings_new.py

@@ -15,3 +15,5 @@
     t"Multiple {first} and {second} placeholders."
 if 6:
     t"Implicit concatenation: " t"Hello, {name}!" t" How are you?"
+if 7:
+    t"With a format specifier: {name:=^20}"

python/extractor/tsg-python/tsp/grammar.js

@@ -1168,7 +1168,7 @@ module.exports = grammar({
     _not_escape_sequence: $ => token.immediate('\\'),
 
     format_specifier: $ => seq(
-      ':',
+      token(prec(1,':')),
       repeat(choice(
         token(prec(1, /[^{}\n]+/)),
         alias($.interpolation, $.format_expression)